Terms of service

The agreement for using HVAC Builder, the licence a supplier gives us for what it publishes, and how content is corrected or removed. Last updated 12 October 2026.

These terms are between you and the operator of HVAC Builder named in section 1. Questions about them: leads@hvacbuilder.app.

In short. This summary is not part of the terms.

HVAC Builder is for professional and business use (section 1).
Your designs are yours. We use them to run the service, and never to train AI models (section 6).
What a supplier publishes stays its own. It licenses us to publish it while it is published, and can edit, unpublish or delete it at any time (section 7).
We pass quote requests to suppliers. We are not part of any deal, and we take no commission (section 8).
The catalog is for designing with, not for copying out (section 5).
Results are engineering estimates. Check them before you rely on them (section 10).

Contents.

1. Who we are and these terms

HVAC Builder, at hvacbuilder.app, is run by Myron Van Staden, a sole trader established in Ireland who trades as HVAC Builder, of 20 Ballydownan, Geashill, Co Offaly, R35 P9F7, Ireland. In these terms "we", "us" and "our" mean that operator. "You" means the person using the service and, where you use it for a business, that business too.

These terms cover everything at hvacbuilder.app: the public pages, the builder at /app, the REST API, the MCP server and the in-app assistant. They also cover a quote request sent from a public page without an account. The plans and prices on /pricing are part of these terms. How we handle personal data is set out in the privacy policy. Where we have agreed terms in writing for an Enterprise account, those win where they differ from these (section 20).

Accepting them. You accept these terms when you create an account, subscribe or buy tokens, register a company as a supplier or publish for it, create an API key, connect an app, or send a quote request. If you use the public pages without an account, these terms apply to that use. If you act for a company, you confirm that you may accept them for it.

Who it is for. HVAC Builder is for people acting for their trade, business or profession. By creating an account, subscribing or buying tokens, you confirm that you use it for that purpose. If you are a consumer, do not subscribe or buy tokens. You must be 18 or over to use the service. If the law where you live still treats you as a consumer and gives you rights that a contract cannot take away, nothing in these terms takes them away.

2. The service

HVAC Builder lets you assemble HVAC systems from components and connect them. It solves their thermodynamic balance, at a design point or across an hourly weather year, alone or as the machines of a building, and reports on the result. Around that it offers a catalog of equipment data, a directory where suppliers publish their equipment, and quote requests routed to suppliers. It has an AI assistant, a REST API, and an MCP server through which an AI agent can work in your account.

Not everything in it is ours. The catalog holds data that equipment makers produced, listed by us; listings that suppliers published themselves; and some generic entries of our own, which name no maker. The directory holds what suppliers publish. Some designs, and one fictional supplier, are published by us as examples: they are marked "Example" or "Fictional", they are not product offers, and a quote request cannot reach them.

3. Accounts and workspaces

You sign in through our sign-in provider. It holds your email address and your password or social sign-in; for your sign-in we hold only the identifier it issues. Keep your sign-in to yourself. An account is for one person: a team works together in a workspace, below. You are responsible for what is done through your account.

API keys and connected apps. An API key, or an app you connect through the MCP server, acts as you, with the same access and the same plan. It can read and change your saved work, spend your tokens, send quote requests in your name, and do in a workspace whatever you may do there — for the workspace's owner, that includes changing the number of extra seats billed to the owner's subscription, and dissolving the workspace. If you are a supplier, it can publish and import listings. It cannot reach admin tools or approve another connection. Only a signed-in session can create a key or approve a connection; you can list and revoke both from one at any time, and a revoked key or connection stops working at once. Treat a key like a password, and connect only apps you trust: what they do in your account, you have done. If you think someone else has used your account or a key, revoke the key and tell us.

Workspaces. On the Business and Enterprise plans, the account holder may create one workspace, and is its owner. It includes 3 seats, the owner's among them, and the owner may add more. Anyone who holds the invite link can join as an editor while a seat is free, so share it with care; replacing the link, or removing a member, stops the old link working. The owner may appoint managers, who may remove editors and viewers and set their roles. An editor saves and changes shared work. A viewer can open and solve it, but not save, change or delete it.

While the owner's plan is Business or Enterprise, members work in the workspace, on that plan: saved systems, components, buildings, runs, weather years and the token balance belong to the workspace. API keys, connected apps, a stored AI provider key and product notes stay personal. While you are in a workspace, the work in your own account is hidden; it is there again when you leave. What you saved in the workspace stays with it. If the owner dissolves the workspace, everything in it — members' saves and bought tokens included — moves to the owner's own account, and members lose access at once. If the owner's plan falls below Business, everyone works in their own account again, and the workspace's work cannot be reached until the plan returns or the owner dissolves the workspace.

As far as we are concerned, the owner controls the workspace and what is saved in it. Who owns the rights in that work between the owner and the members — an employer and its staff, say — is for them to settle.

A workspace has one supplier identity: the owner's company. Members without a supplier profile of their own work on it. Editors manage its listings, offerings and leads; only the owner edits the company profile and claims or releases brands.

4. Plans, tokens and payment

Plans. There are five plans: Free, Starter, Professional, Business and Enterprise. What each includes, and what it costs, is on /pricing. Enterprise is priced on request and set up on your account by us; write to leads@hvacbuilder.app.

Tokens. Solving, simulating, reports, the bulk catalog and the assistant on our AI key are paid for in compute tokens. The documentation (/docs/annual and /reference/rest) sets out what each costs, and section 11 gives the assistant's rate. Every plan includes a monthly allowance. It starts again on the first day of each calendar month (UTC), and what is left unused does not carry over. Tokens you buy, and tokens we give back, do not expire, and are spent after the month's allowance. When your plan changes, the month's allowance becomes the new plan's, less what you have used this month. A charge is taken whole or not at all. An answer from the REST API that charges tokens says what it took and the balance it left; you can read your balance in the app, and over MCP with the my_account tool. Tokens are not money. They have no cash value and cannot be sold or transferred, except that a workspace's tokens are shared by its members (section 3).

What happened	What it costs
A request refused before anything is solved — invalid, short of tokens, or the server or your account too busy to start it	Nothing
A solve that runs and does not converge	Charged: the work was done, and the answer says why it stopped
A solve stopped for running past its time budget, or lost to a fault of ours	Refunded
A run you cancel	The hours not yet computed are refunded
A run that fails on the design or the weather	The hours not computed are refunded; the hours computed stay charged
A run the server loses — a fault, a restart, a crash	Refunded in full
An assistant message the AI provider does not answer	Refunded

Tokens are refunded as tokens, which do not expire.

Paying. Prices are in US dollars. Checkout may show them in your local currency; if it does, you pay the amount it shows. Payments are taken by our payment processor, Stripe; your card details go to it directly and never reach our servers. A plan is a subscription: it is charged when you subscribe and then at the start of each monthly period, until it is cancelled. Where /pricing shows a first-month discount, it applies once, to the first month. Extra workspace seats are billed monthly on the owner's subscription, prorated when their number changes. A token top-up is a single payment, and its tokens go to the balance you spend from — the workspace's, if you work in one.

Taxes. We are not registered for VAT, and add no VAT or sales tax to our prices. Where the law makes you account for a tax yourself — under a reverse charge, for example — you do.

Changing plan. To move to a higher plan, choose it in the app and pay for it at checkout. The new plan starts when its checkout is complete, and the plan it replaces ends then: the unused part of the period you paid for under the old plan is credited to your account, and the credit is taken off your next invoices. If you are ever charged for two plans at once, we refund the overlap in full. To move to a lower plan, or to stop, cancel the subscription, below.

Cancelling. You may cancel a subscription at any time, in the app: the account menu, Manage account, Plan, Cancel plan. Cancelling takes effect at the end of the period you have paid for. The plan stays until then, and you can take the cancellation back with Keep my plan; after that, the account is on Free. We confirm a cancellation by email. If you cannot use the app, write to leads@hvacbuilder.app from the address your subscription is billed to, or the address you sign in with, and we will cancel it for you. A plan we set up for you by hand is cancelled the same way, by writing to us.

When a plan ends or drops. Saved systems and buildings are not deleted: they stay listed and readable, and a new save past the lower plan's limit is refused. Saved runs past the lower plan's limit are deleted, oldest first, the next time a run starts — on Free, every run but the one just started. If a payment fails, the account may move to Free until it is paid, and then the plan resumes; a run started in the meantime deletes runs as it would on Free, and they do not come back.

Refunds of money. We do not refund part of a period, unused tokens, or a plan you did not use, with these exceptions: the overlap of two plans, in full (above); a charge made in error; and, if we close your account without a breach on your part or end the service, the unused part of the period you paid for and the bought tokens you had not spent, at the price you paid. Sections 17 and 20 add others. The law may give you more, and nothing here takes that away.

Price changes. We may change prices, and what an operation costs in tokens, which is part of what you pay. A change applies to you only from 30 days after we tell you by email — for a subscription, from the first period that starts after that. You may cancel before then.

Plans and tokens we give. We sometimes give a plan, seats or tokens without payment — a trial, a credit, an arrangement with a partner. They last as we said when we gave them. Unless we agreed otherwise in writing, we may end a plan we gave with 30 days' notice; tokens we gave stay until they are spent.

The Free plan. What you design, solve and save on the Free plan you may use for any lawful purpose, commercial work included. Reports, chart exports and shared run pages from a Free account carry an evaluation watermark. They are for trying the service: do not hand them to a client or submit them for approval, and do not remove or hide the watermark. Reports on the paid plans carry none.

5. Acceptable use

Use the service for what it is for — designing, solving, reporting on, listing and quoting HVAC equipment — and within the law. In particular:

Do not harvest the catalog. The catalog is for designing with. The public pages, and one machine's full data at a time for any account, are free; the whole catalog in one answer costs 25 tokens. Read it those ways. Do not copy the catalog, or a substantial part of it, by scraping pages, by spreading requests over many addresses or accounts, or by calling the API or a connector item by item to rebuild what the bulk routes sell. What you read is for your own work: your designs, selections, reports and quote requests. Do not republish it, sell it, load it into another database or product — an AI agent you connect through the MCP server, to do your own work here, excepted — or use it to train or test a machine-learning model. Paying for the bulk answer buys it for that use, and no other. These are the terms on which we give access to the catalog; they claim no ownership of the makers' and suppliers' figures in it.

Programs and crawlers. Programs may use the service through the REST API with an API key, and through the MCP server. Search engines may crawl the public pages that robots.txt allows, to index them. If catalog figures are read faster than a person reads them, the site holds them back for a few minutes, and the API answers "too many requests". That is a limit on speed, not a judgement on you, and nothing shown is ever altered. So far as we hold rights in the catalog as a database, we reserve them from text and data mining under Article 4(3) of Directive (EU) 2019/790.

Do not get round the limits. Do not open extra accounts, or share one among several people, to multiply what a plan includes — tokens, free assistant messages, example runs, quote requests; a team uses a workspace. Do not bypass the rate limits, the token meter, a plan's limits or the watermark. Do not use someone else's account, key or connection without their consent.

Do not misuse quote requests. Send one only for a real enquiry, with your own contact address. Do not use quote requests, or the leads you receive, to send spam.

Do not attack the service. Do not probe, scan or test its security without our written permission, overload it, interfere with other people's use of it, or try to reach data that is not yours. If you find a vulnerability, report it to bugs@hvacbuilder.app, do not use it, and tell no one else until we have had a reasonable time to fix it.

Do not upload what you may not. Nothing unlawful, deceptive or harmful: no malware, nothing that infringes someone's rights, and no one else's personal data without a lawful basis.

Use the assistant fairly. Do not use the assistant to produce anything unlawful or harmful, to get round its limits, or to build a competing AI service. The usage policy of the AI provider named in the privacy policy also applies to what you ask it.

Sanctions. You confirm that you are not named on a sanctions list that applies to you or to us, that you do not act for anyone who is, and that you will not use the service from, or for, a country or region under comprehensive sanctions. We may refuse or close an account where serving it would break sanctions or export law.

We may limit, suspend or close access that breaks this section (section 16).

6. Your designs and data

Your designs are yours. The systems, components, buildings and runs you make, and the weather years you import or generate, are yours. We claim no ownership of them.

The licence we need. So that we can run the service, you give us a non-exclusive, worldwide, royalty-free licence to host, store, copy, process and back up what you put into it; to solve and simulate it; to show it to you and to the people you choose — your workspace, the holders of a run you share by link, the suppliers you send a quote request to — and, when you use the assistant, to pass what it reads to the AI provider (section 11); and to produce the reports and exports you ask for. It lasts while the content is in the service and, after you delete it, until the last backup copy is gone (section 7.1); for a quote request you have sent, it lasts as long as the supplier keeps it (section 8). We do not sell your designs or your personal data, and we do not use your designs to train AI models.

Confidentiality. We keep what you have not published confidential. We use it only to run the service, show it only to the people this section names and to the providers that run the service for us (section 12), and protect it with measures suited to it — unless the law requires us to disclose it.

What you upload. You confirm that you may use what you put in — a maker's figures typed from a datasheet, an imported weather file, an image — and that its use here breaks no one's rights.

Counts, not content. We count what the service does — solves, simulations, saves, quote requests — with nothing about who did it. When your design uses a supplier's listing, that supplier sees how often the listing was solved with, simulated, reported on and saved: never by whom, and never the design.

Sharing. A finished building run can be shared by link. Anyone holding the link sees its results, never the design, until you stop sharing it or delete the run. A quote request carries your contact email, your message, what you are asking about — an item, or a summary of your design — and, if you are signed in, your account's identifier. The full design goes only if you tick the box to share it. What happens to a request once it is delivered is in section 8.

Deleting. In the app you can delete any saved system, component, building or run, revoke a key, disconnect an app, or remove a stored AI provider key; a weather year of your own is deleted through the API or an MCP connector. Each takes effect at once and removes the record, not a flag on it. Deleting a run that is still running cancels it, and the tokens for the hours not computed come back.

Copies. You can read your work back one item at a time: saved systems, components, buildings, runs and their results as JSON over the API or MCP, a report as HTML or PDF, the component schedule as CSV. For a copy of everything filed under your account, write to privacy@hvacbuilder.app: we send it within 30 days, at no charge, as JSON — saved systems, components, buildings, runs and their results, weather years of your own and, for a supplier, its profile, listings, offerings and leads. Keep your own copies of work that matters.

Publishing a design. A supplier that publishes a design as an offering makes it public: anyone can open the whole design in the builder. Section 7 sets out the licence that comes with publishing.

7. Supplier content and the content licence

Any signed-in account can register a company as a supplier, free — a workspace member works on the owner's (section 3) — with a company name and a contact email that quote requests are sent to, or, by region, to the reps you name. By registering you confirm that you may act for the company, and these terms then bind it. A supplier's content is everything it publishes or uploads: listings of equipment the builder models; listings of accessories, which the builder lists but does not model; offerings, which are whole system designs; and its company profile, with its logo, description, website and capabilities.

	Free	Supplier tier — on the Business and Enterprise plans
Listings published at once	3, accessories included; drafts and offerings do not count	No tier limit
Matched quote requests (section 8)	Received while fewer than 20 leads have arrived in the last 30 days — past that you are told how many you missed; the portal shows the newest 20	Every match
Email of a matched request	24 hours after it arrives; it is in the portal at once	At once

On any plan a supplier may hold up to 25 offerings, 40 listings of one modelled kind, 40 accessories in one category and 400 accessories in all — drafts and unpublished items included — and we keep its newest 500 leads. Direct quote requests from its own pages reach it on every plan. A supplier subscription bought before 30 September 2026 continues until it is cancelled. Registering and publishing within these limits cost nothing, and we take no commission (section 8).

7.1 The content licence

Your content stays yours, with every right you have in it. You give us a non-exclusive, worldwide, royalty-free licence, with the right to sublicense it to the providers that run the service for us and to users as this section describes — for as long as an item is published, and after that as set out under When it ends — to:

host, store, copy and back it up, and serve its images from this site, resized or re-encoded for the web;
publish it on its own public page, on your company page, in the directories and their search, and in the sitemap, with the structured data and preview image that search engines and link previews read;
set it inside our pages — headings, labels, table heads, category and attribute names — in any of the site's languages, and show its figures in SI or US units. We never translate or rewrite your own words. We may trim spaces, drop a repeated tag, and shorten your text, with an ellipsis, where a directory tile, a list or a search result has room for less;
run its figures in our model, and publish what they give — a compressor's capacity, input power and COP at one rating point, read from its map, and an offering's performance at its design point, which its page says we solved;
let users pick it into their designs and solve with it, keep its figures in the designs they save, print it in their reports and schedules, and send quote requests about it;
make it available through our REST API, the catalog's metered bulk routes, the public product search and the MCP server, and to the in-app assistant, which passes what it reads to the AI provider named in the privacy policy;
let anyone open a published offering's design in the builder, and save, change and solve a copy of their own; and, where you tick allow reuse on an offering, let other suppliers build it into offerings of their own;
show your company's name and logo with your content, and wherever we name you as a supplier;
show your listings, name and logo in screenshots and demonstrations of the service. If you ask, we stop making new ones that show you.

Users may go on using your content in their own designs, reports and quote requests, for their own projects, within section 5. Drafts and items you have not published are held under section 6. For content you published before these terms first took effect, this licence applies from that date, and you confirm the permission you gave us by publishing it before then.

When it ends. The licence to publish an item ends when you unpublish or delete it. Its page and images go at once — the address answers "not found" — and it leaves the directories, the sitemap, the catalog, the product search and quote routing: a listing at once, an offering within a minute. Some copies remain, and the licence continues for them:

what users saved before you withdrew it — a listing's figures in their designs, which go on solving with a warning that the listing is gone, and their own copies of an offering — and the reports, schedules and quote requests already made with it;
copies of an offering that other suppliers built into their own while you allowed reuse;
our nightly backups of the database, kept only to recover the service from a failure; each is deleted by the first nightly backup to complete once it is more than 14 full days old;
copies others made while it was public — search engines, caches, link previews — which we do not control.

For the first two, the licence is perpetual and irrevocable; for the backups, it lasts until each is deleted. Unpublishing keeps the item in your account, to publish again. Deleting removes the record itself and cannot be undone.

7.2 Your promises

For everything you publish or upload, you promise that:

you own it, or have the right to publish it under this licence — text, figures, images, logos, trade marks and designs — and its use as described here infringes no one's rights;
the authors of its text and images have consented to their use as this licence describes, so far as the law lets them;
its figures are accurate and current: the ones you sell the product on, at the conditions you state;
a certification you name is held by the product you list it on;
what you say about your company is true;
what you publish complies with the law where you offer the product, including the law on advertising and product information.

If any of it stops being true, correct or withdraw it promptly. Use another company's name, logo or model names only to say truthfully what your product is, replaces or fits — never to suggest that you are that company, or that it endorses you.

7.3 What content may not contain

Contact details in the text — email addresses, phone numbers, messenger names or links. Your website, product page and datasheet each have a field of their own, and quote requests reach you through us. In an accessory listing's text, and in a published listing's tags, markets and certification, the app refuses such details.
Figures you know to be wrong, or a rating or certification the product does not hold.
Images, text or data from another company that you have no right to use.
Products you do not make or supply; copies of your own listings (the app refuses an identical one); text written for search engines rather than readers.
Anything unlawful, deceptive, defamatory or harmful; malware; characters that hide or reorder text.

Images must be your own photographs, renderings or drawings, or ones you have the right to use: PNG, JPEG, WebP or GIF, a cover and up to 2 more.

7.4 Links

A listing or an offering may link its product page, an accessory listing its datasheet too, and your profile your website. Each must be an http or https address that leads to the product or to your company. We decide how links are marked for search engines, and may change it. We do not promise any ranking, traffic or number of leads. We may remove a link that leads anywhere unlawful or harmful.

7.5 How content is checked

Some checks are automatic, and run when you save. The app refuses a published listing that lacks the figures it is sold on. It refuses contact details in the places 7.3 names, an image of the wrong type or size, and an identical copy of one of your listings, and it says why. These checks refuse a save; they never take down what is already published. Everything else is decided by a person. We check a certification against the programme's public register before we mark it verified, and any edit sends it back to be checked. We confirm brand claims by hand. A person reads every notice we receive (section 19).

We may refuse to publish, unpublish or remove content, or suspend a supplier, where content breaks these terms or the law, or after a valid notice. When we do, we tell whoever published it, by email to the supplier contact address, at the latest when the restriction starts: what we did, where it applies and for how long; the facts it rests on, including whether it followed a notice or our own review, and whether anything automated was involved; the law, or the term of these terms, it rests on; and how to contest it — unless the law forbids us to say. Reply to that email to ask us to look again; we will, and we will tell you the outcome. Where the Digital Services Act gives you the right, you may also take the decision to a certified out-of-court dispute settlement body, and you may always go to court.

7.6 Correcting and removing your content

From the Company tab in the app you can, at any time:

edit a listing, an offering or your profile — logo, description, website, contact email and capabilities. A saved change shows on the public page at once, and a listing's corrected figures reach every design that picked it at that design's next solve;
unpublish an item: its page goes down at once, and it leaves every directory, search and quote route — an offering's directory entries within a minute — while the record stays in your account, to publish again;
delete an item: the record itself is removed, not marked. Its page answers "not found", links to it break, and it cannot be undone;
hide your company page: it answers "not found" and leaves the company directory, and your published items keep their own pages, which name your company without linking to it;
release a brand you hold, or withdraw a claim that is pending.

The app cannot delete a supplier profile, or an account. To have either deleted, with everything filed under it — listings, offerings and leads included — write to privacy@hvacbuilder.app from your supplier contact address, the address your subscription is billed to, or the address you sign in with. We do it within one month of receiving the request — if we must first confirm that it is yours, we ask at once — and tell you when it is done. Your company page's address is made from the company name when you register and does not change; once the profile is deleted, it answers "not found".

If you cannot make a correction yourself — a listing in our own catalog under a brand you hold, say (section 9) — write to leads@hvacbuilder.app, naming the listing and the change.

8. Quote requests and leads

We pass enquiries; we are not part of the deal. A quote request goes from a buyer to suppliers through us. We deliver it and step out. We are not a party to any quotation, order or contract between buyer and supplier, and we handle no payment between them. We take no commission on leads, and will not. Whether to quote, and everything that follows — price, delivery, warranty, the goods and their compliance — is between buyer and supplier. Beyond what these terms describe — a certification we marked verified, a brand claim we confirmed — we do not vet suppliers, and we do not promise that anyone will answer.

Direct and matched requests. A direct request — from a listing's or an offering's page, with or without an account, or from the builder — reaches only the supplier of the items it names. A matched request is sent on a paid plan, from the builder, the API or a connector. The buyer chooses its recipients from a list of the suppliers whose declared capabilities or published accessories cover what is asked, or who hold a brand the design uses. That list puts suppliers on the supplier tier first. Then it ranks them by fit. For a system or a component, fit is how near the duty sits to the middle of the capacity range the supplier declared, and a supplier that holds a brand the design uses fits fully; for accessories, fit is the share of the requested lines the supplier covers. Then it ranks them by how complete their declaration is — a certification, a lead time, and their refrigerants or a published listing that backs the match — and last by name. Every supplier the buyer chooses receives the request, wherever it sits in the list. A free supplier over its monthly lead limit is left out of the list, and told that it missed a request. The directories' default order puts real listings before examples, and takes turns between categories, makers and series, the newest first; payment plays no part in it.

Limits. On a paid plan each person may send 5 matched requests in any 24 hours, and the same request once a day; the Free plan can see who would be asked, but not send. Requests from a public page without an account are limited to 5 an hour from one address, and 5 an hour for one email address. Each supplier keeps its newest 500 leads; older ones are deleted as new ones arrive.

Delivery. A lead appears in the supplier's portal at once. By email it goes at once, in a daily digest, or not at all, as the supplier chooses — except that a free supplier's email for a matched request goes 24 hours later, and a free supplier's daily digest holds only the leads that arrived at least 24 hours before it is sent. A reply to the lead email goes straight to the buyer. We do not promise that a request or a lead is delivered, or how many leads you receive.

Using a lead. A supplier may use a lead to answer the enquiry and to follow it up. It may not sell or pass on the buyer's details, or add them to a mailing list, without the buyer's consent. A design the buyer shares may be used only to answer that request, shown only to the people who help to answer it, and never published or reused. Once delivered, a lead is also the supplier's record, and from then on the supplier answers for how it handles the buyer's details: under the data-protection law that applies to it, kept secure, and deleted when the buyer asks, unless the law requires it to keep them.

9. Makers' data in the catalog

Where it comes from. Much of the catalog is listed by us from equipment makers' own data: their documents, catalogues and selection software. We record the source of each dataset and convert it to the form the model runs, checked against the maker's own figures. So a listing's figures come from its maker's data: as printed, read from the maker's curves, or, for some compressor ranges, the AHRI 540 form fitted to the maker's own tables. The model that runs them is ours. The catalog's generic entries, which name no maker, are our own representative figures.

What a listing does not mean. Unless its page says so, a listing does not mean that the maker has reviewed it, or our model of its product — even where the maker has claimed its page. Where a page derives a figure from others — an emitter's output net of an allowance, a burner's efficiency — it says how; a compressor's capacity, power and COP at a rating point are read from its map. Where a maker's printed figure fails our physical checks against its own neighbours, we may leave it out, so a listing can differ from a cell the maker printed. Makers' names, model names and trade marks belong to their owners; we use them to identify the products, and their use implies no endorsement.

Corrections and removal, for makers. A maker who finds a figure wrong, or does not want a listing here, can write to leads@hvacbuilder.app from its own email domain, or with other proof that the writer acts for it, naming the listings. We correct what is wrong, and take down what a maker asks us to take down. We aim to acknowledge a request on the working day it arrives, and to make the change within two working days. A withdrawn listing leaves the service, and our own examples stop using it. Designs that saved a copy of its figures keep that copy (section 7.1), and our private development records keep the history of the change, which nothing in the service reads.

Claiming a brand. A maker can claim its page from the Company tab, if the company name it registered names the brand, or by writing to leads@hvacbuilder.app. We confirm each claim by hand — normally once the claimant has written to us from the maker's own email domain — and until we have, nothing public changes. Once a claim is confirmed, the maker's page and its listings are attributed to the claimant's company, and it is offered as a recipient of the matched quote requests for designs that use those listings (section 8). A claimant edits or withdraws a listing under its brand by telling us, and we aim to make the change within two working days, as for any maker. One company holds a brand at a time. A claim can be released at any time, and we may revoke one that proves mistaken. A claim changes attribution and routing, never what the solver computes.

Certification marks. A certification on a supplier's listing is the supplier's own claim until we have checked it against the programme's public register; then it carries a ✓, which any edit clears. A ✓ means that when we checked, the programme's public register named the product, or its line where the page says so. Registers change: check the register before you rely on it. The programme has not reviewed our page, and the ✓ says nothing about our model of the product.

10. Engineering results

Results are estimates. What HVAC Builder computes — duties, powers, efficiencies, states of air and refrigerant, annual energy, unmet hours, ratings, the figures in reports — comes from models running on catalog data and published correlations. These are engineering estimates. They are not certified ratings, not measurements, and not a maker's selection. /validation shows how the model reads against published data and lists what is not validated, and building results come from a deliberately simple zone model.

A solve that does not converge is reported as an error, never as a partial result, and a machine run outside its declared envelope is named in the solution. Read those messages and the solution's warnings: they are part of the answer. Their absence is no assurance.

Your judgement is required. The service is a tool for qualified people. Before you rely on a result to size, select, specify, buy, build or commission anything, check it with your own professional judgement and against the maker's own selection data. Catalog figures can be out of date or wrong: check them against the maker's current data. Compliance with codes, standards, regulations, permits and safety requirements — refrigerant charge limits, pressure equipment, electrical and building codes, ventilation and energy rules — is yours. We do not give engineering advice, nothing in the service is a design approved for construction, and using it creates no professional relationship between you and us. Where the law requires a licensed engineer to approve a design, that is you or someone you engage.

Safety and ratings. Do not use a result as the only basis for a decision that affects safety: refrigerant charge and flammable or toxic refrigerants, pressure equipment and its relief, ventilation, cooling towers, electrical sizing. A figure we compute, such as an IEER or a COP at a rating point, is not a certified rating: do not present it as one, or use it in a regulatory filing, on a label or in a tender, without the maker's certified data.

Who results are for. Results, reports and shared pages are made for the account holder. We owe no duty to anyone else who reads them. If you pass them on, you do so on your own responsibility: keep the statement that they are estimates, and do not present them as ours or as a maker's rating.

To the extent the law allows, we give no warranty that results are accurate, complete or fit for any purpose. Section 14 limits our liability.

11. The AI assistant

The in-app assistant reads the design you have open, changes it, solves it, saves new systems and buildings, runs simulations and fetches weather, when you ask it to. It cannot change or delete saved work, send quote requests, or publish or import listings. A change it makes to your design lands as an edit you can undo.

Check what it says and does. The assistant is an AI model. It can be wrong, and sound sure: it can misread a request, pick an unsuitable part or explain a result badly. Its answers are not engineering advice. As between us, what it produces for you is yours, and section 10 applies to it. The solves and runs it starts spend tokens like any others.

Plans and metering. The assistant is part of the Starter plan and up. On the Free plan, an account may send 3 messages on our AI key, free, and that number does not renew. Otherwise each message on our AI key costs 50 tokens, every message on our key counts toward a daily limit, and the tokens of a message the AI provider does not answer are refunded. You may instead store your own AI provider key: your chats then run on it, unmetered by us and billed by your provider under its own terms. We store that key as you give it, because it has to be sent to the provider as it is, and we use it only for your chats. You can remove it at any time.

What reaches the provider. The messages you send, and what the assistant reads to answer them — your open design, your saved buildings, the list of your weather years, the catalog, the published offerings, and the results of the solves and runs it starts — go to the AI provider named in the privacy policy. Your conversation is kept in your browser, not on our servers; we log only how many tokens each message used.

Your own agent. Through the MCP server, an AI agent of your choice can work in your account as a connected app (section 3). What that agent's provider does with what it reads is governed by that provider's terms.

12. Third-party services

We rely on a small number of providers to run the service: sign-in, payments, email delivery, the mailboxes we read, the AI assistant, hosting, and a public file network that serves some label glyphs. The privacy policy names each one and says what reaches it. Payments are also subject to our payment processor's terms, and an AI provider key you store to that provider's.

Weather years fetched for a city come from PVGIS, © European Union, JRC. Refrigerant properties are computed with CoolProp, an open-source library. Open-source components of the service are used under their own licences.

Links to suppliers', makers' and other sites lead to pages we do not control, and we are not responsible for them.

13. Intellectual property and feedback

Our software, our model, our pages and documentation, the layout of our reports, the catalog's generic entries, which name no maker, and the name HVAC Builder are ours. Makers' and suppliers' data in the catalog remains subject to their rights, and our work in converting it gives us no rights over theirs. We give you a non-exclusive, non-transferable right, for you and the people who work with you in a workspace, to use the service under these terms. Nothing else is licensed to you.

Your reports. You may copy, print and share the reports, schedules, charts and exports you make, for your own projects and with your clients, subject to the Free plan's watermark (section 4) and to section 10. They carry makers' and suppliers' names and figures: do not use them to republish the catalog.

Feedback. If you send us ideas or suggestions, you give us a perpetual, royalty-free licence to use them, and we owe you nothing for them. A design snapshot attached to a bug report is seen only by us, and used only to look into the report.

14. Disclaimers and liability

As it is. The service is provided as it is and as available. To the extent the law allows, we exclude every warranty and condition not written in these terms, including those of accuracy, merchantability, satisfactory quality, fitness for a purpose, non-infringement, and uninterrupted or error-free operation. We may take the service down for maintenance; while a new version is deployed, a maintenance page shows for a short time.

What we are not liable for. To the extent the law allows, we are not liable for loss of profit, revenue, business, contracts, goodwill or anticipated savings; for loss or corruption of data; for the cost of substitute services; or for any indirect or consequential loss, whatever the cause of action. Nor are we liable for decisions made on results without the checks section 10 asks for, for content that suppliers publish, for dealings between buyers and suppliers, or for outages of the providers in section 12. Our own catalog listings, computed figures and certification marks come with no promise beyond what sections 9 and 10 say.

The cap. Our total liability to you for all claims together, whether in contract, tort (including negligence), breach of statutory duty or otherwise, arising from or in connection with the service or these terms, is limited to the greater of: what you paid us in the twelve months before the event that gave rise to the first claim; and US$100.

What we do not limit. Nothing in these terms limits or excludes liability for death or personal injury caused by negligence, for fraud or fraudulent misrepresentation, or any other liability that the law does not allow to be limited or excluded. If you are a consumer, you keep the rights that the law gives you and a contract cannot take away.

15. Indemnity

If you use the service for a business, you will compensate us for the losses and reasonable costs, legal costs included, that follow from a claim someone else makes against us that arises from:

content you published or uploaded that infringes their rights or breaks the law;
your breach of these terms;
your dealings with a buyer or a supplier you met through the service; or
your use of results, reports, schedules or shared pages, including a claim by your client or anyone else who relied on them.

This does not apply to the extent that the claim arises from our own breach. We will tell you promptly of such a claim, let you lead its defence where the law allows, and not settle it without your consent, which you will not unreasonably withhold.

16. Suspension and termination

You may stop at any time. Delete what you want gone (section 6) and cancel a subscription (section 4). To close your account, write to privacy@hvacbuilder.app as section 7.6 describes, and ask first for a copy of anything you want to keep (section 6). Deleting your identity at our sign-in provider does not close your account here, and leaves what is filed under it: write to us.

We may suspend or close access — to an account, a key, a connection, a supplier or a listing — where you seriously or repeatedly break these terms; where your use puts the service, its users or others at risk; where the law or an authority requires it; or where you do not pay what you owe. Where we can, we warn you first and give you the chance to put things right. Unless the law requires us to act sooner, or you have repeatedly broken these terms, we give a supplier 30 days' notice before ending its account for good. Whenever we restrict an account or what it published, we tell its holder, at an address we hold for them (section 19), what section 7.5 lists — unless the law forbids us to say. We may also end the service as a whole, with at least 30 days' notice to account holders.

What happens to your data. When an account closes, at your request or ours, we delete what is filed under it: saved systems, components, buildings, runs and weather years; keys, connections and a stored AI provider key; product notes; its token balance; and a supplier profile with its listings, offerings and leads. We also remove the quote requests it sent from suppliers' portals; copies already emailed to suppliers are theirs. If we close an account ourselves, for any reason but illegal content, we keep what is filed under it for 30 days after we tell its holder, so that they can ask for a copy (section 6), and then delete it. We cancel any subscription at once, without a refund of the current period except as section 4 provides, and tokens left over lapse, except the bought tokens section 4 refunds. Copies others hold under the licences in sections 6 and 7 stay with them; nightly backups keep a copy until each is deleted (section 7.1); and we keep what the law requires us to keep. If you own a workspace, it is dissolved first: what it holds moves to your account and is deleted with it, and its members lose access — tell them before you go.

17. Changes

To the service. The service changes often: features, limits and the catalog come and go, and the changelog records what changed. We may change or withdraw a feature. Where a change takes away something you pay for, we tell you first; if you cancel because of it, we refund the unused part of the period you paid for.

To these terms. We may change these terms, and will post the new version here with a new date. For a change that matters to you — your rights, your obligations, what you pay, or the content licence — we will tell account holders by email at least 30 days before it takes effect. For a change to the content licence, to section 14 or to what you pay, we will also ask you to accept it the next time you sign in. A change that the law or the security of the service requires may come sooner. If you use the service after a change takes effect, the new terms apply to you; if you do not accept them, stop using the service and close your account before then. If you end a paid plan because of a change that is to your disadvantage, we refund the unused part of the period you paid for. A change does not reach back to what happened before it.

To free listing. Registering a company and publishing within the free supplier limits cost nothing today. If that changes, or a free limit is lowered, suppliers will be told by email to their supplier contact address at least 30 days before, and may withdraw anything before then. Price changes follow section 4.

18. Governing law and disputes

These terms, and any dispute about them or the service, are governed by the law of Ireland. The courts of Ireland have exclusive jurisdiction. If you are a consumer, you may also bring proceedings where you live, and the mandatory law of your country still protects you.

Before going to court, write to us (section 19) and give us 30 days to put the matter right. Nothing stops either of us from asking a court for urgent relief.

19. Notices and contact

What	Where
Questions, corrections, brand claims, Enterprise; cancelling, if you cannot use the app	leads@hvacbuilder.app, or the contact form
Bugs and security vulnerabilities	bugs@hvacbuilder.app, or Feedback in the app
Privacy, a copy of your data, closing your account	privacy@hvacbuilder.app
Illegal content	leads@hvacbuilder.app, with "Notice" in the subject, or the contact form
Complaints about our decisions on content	A reply to our decision, leads@hvacbuilder.app with "Notice" in the subject, or the contact form
Authorities	leads@hvacbuilder.app, with "Notice" in the subject
Formal legal notices	By post to the address in section 1, with a copy to leads@hvacbuilder.app

The contact form shows us the address you type, not where a message came from. A request these terms ask to come from a particular address — a cancellation (section 4), a maker's correction, takedown or brand claim (section 9), or the deletion of an account or a profile (section 7.6) — may be sent through it, and we act on it once you confirm it by replying, from that address, to the email we send you. A request you confirm counts from the day your message reached us (section 20). A maker's request that carries other proof that the writer acts for it is handled as section 9 describes.

A person reads every message to these addresses and from the contact form. Under the Digital Services Act, our single point of contact for users (Article 12) is leads@hvacbuilder.app, and you may also use the contact form or Feedback in the app; our single point of contact for the authorities of the EU member states, the European Commission and the European Board for Digital Services (Article 11) is leads@hvacbuilder.app, with "Notice" in the subject.

We write to you at an address we hold for the purpose: your supplier contact address, the address your subscription is billed to, the address you wrote from, or the one our sign-in provider holds for your account. A notice by email counts as given on the day it is sent. Our points of contact can be written to, and answer, in English, an official language of Ireland, where we are established.

Reporting illegal content

Anyone can tell us about content on HVAC Builder that they believe is illegal — a listing that infringes a copyright or a trade mark, a false certification, an unlawful product — by writing to leads@hvacbuilder.app with "Notice" in the subject, or through the contact form. Include:

the exact address (URL) of the content;
why you believe it is illegal, and the law or the right concerned;
your name and email address (not needed for a notice about child sexual abuse material);
a statement that you believe, in good faith, that the notice is accurate and complete.

A person reads every notice, and no decision on one is automated. We confirm that it arrived, look at the content promptly and with care, and tell you what we decided and how to contest it. If we remove or restrict the content, we tell whoever published it why (section 7.5). Either of you may ask us to look again by replying to our decision, and may go to court or, where the Digital Services Act gives the right, to a certified out-of-court dispute settlement body. Anyone, in the United Kingdom as elsewhere, may complain to us in the same way, or through the contact form, about how we handled a notice, or about content of theirs that we removed or restricted; we look at each complaint and tell you the outcome. Where content suggests a crime that threatens someone's life or safety, we inform the authorities. If someone keeps sending notices that are plainly unfounded, we may warn them, and then stop handling their notices for a time.

20. General

These terms, with /pricing and any written Enterprise agreement, are the whole agreement between us about the service, and you have not relied on anything else; this does not limit liability for fraud. Where they differ, a written Enterprise agreement prevails, then these terms, then /pricing. Other pages of the site describe the service; where they differ from these terms, these terms apply.

If a court finds part of these terms unenforceable, the rest still stands. If we do not enforce a right at once, we have not given it up. You may not transfer your rights or obligations under these terms without our consent; we may transfer ours to whoever takes over the service, and will tell you. Nobody else has rights under these terms. Nothing in them makes us partners, or makes either of us the other's agent.

Neither of us is liable for a failure caused by events beyond our reasonable control. This does not excuse a payment. If such an event lasts more than 60 days, either of us may end a subscription, and we refund the unused part of the period you paid for.

Sections 6 and 7 (for the copies that survive), 14, 15, 18 and 20, and any payment due, survive the end of these terms. A notice to us counts as given when it reaches an address in section 19. These terms are written in English; if they are ever translated, the English text is the one that counts.