A Sigma listing, from the manufacturer's published data.

Units: SI · US customary

Published specification

Nominal output	0.248 kW per foot of active length (0.813 kW/m) — the maker's rating as printed, 846 Btu/h per foot: its document states no heating-effect allowance
Rated at an excess of	52.8 K of water over 18.3 °C (65 °F) entering air — 71.1 °C (160 °F) average water
In a room	a 20.0–21.1 °C (68–70 °F) room reads 4.1–6.8 % under the tested rating at 71.1 °C (160 °F) average water: the model takes Δt over the air entering the part, which in a building is the room's, and the rating was taken over 18.3 °C (65 °F) entering air
Exponent n	1.3 — the output follows (Δt/Δtn)^n

Manufacturer's product page

Open this part in the app — as a component of its own, carrying the catalog's figures; or open the builder and pick it from the catalog picker. The solver runs it with the catalog's own data, at your design point or across a year of weather.

How the model reads against this maker's data

Panel radiators rated per foot, against their maker's own tables: the emitter's power law read from the one column the maker's correction table does not generate, carried to the others by the model's default exponent — none being measured

784 printed cells; 112 listings

listed at the 160 °F column (52.8 K over 65 °F) with the model's default exponent, 1.3 — Sigma's own correction table, the generator of the other columns, is no power law (read as one it implies 1.19 to 1.47 column by column) — the model reads every printed cell within −3.97 to +1.98 %, through the forward pass at each column's mean water. In a room, as for every rating over 65 °F entering air: a 68–70 °F room reads 4.1–6.8 % under the tested rating at 160 °F, which the listings' pages state

From the validation page; every row is held by a test.

Listed from published data; a listing's figures are the manufacturer's, the model that runs them is ours. Solver results never depend on who has claimed what.