[minerva23]

Article:

> The energetic output of an oven stove is 80 to 90 percent, compared to 40 to 50 percent for metal stoves or central heating appliances

Energy.gov

> Old furnaces: 56% to 70%

> Mid efficiency furnaces: 80% to 83%

> High efficiency furnaces: 90% to 98.5%

https://www.energy.gov/energysaver/furnaces-and-boilers

EDIT: We can cut the article some slack as ducting (as typically done) does account for losses which are highly variable.

[phgn]

Well, what does "energetic output" mean? If I understand the core point of the article correctly, radiant heat only heats the surface of objects not the air, so it will require less heat for the same effect. I don't how to put a number on this.

I think the energy.gov article you mentioned primarily talks about heat leaking outside:

> An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere.

[stonkdonk]

this article lost me when I saw those numbers. It also treats heat like some kind of magic and not based on thermodynamics. heat is heat, no matter how quickly or slowly it spreads. A big thermal mass will hold heat, but will also take longer to heat in the first place. You're spending the same number of BTUs in the long run.