Heat loss calculator?

[DZL JIM]

Sorry if this has been beaten to death, but searches turned up nothing.

Does anyone have a good, easy to use heat loss calculator for a garage/shop?
Trying to size a new boiler for slab heat. The supplier said they'd do it for me, but I am too hands-on to let this one slide. They have a new old stock boiler they want to make a deal for me but I want to make sure it's adequate in size.

Thanks.

 

[jbs]

I like this one:
http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

Not perfect, but useful and pretty easy.

 

[danski0224]

The radiant manufacturers have design tools on their websites.

Watts

Taco

B&G

In no particular order.

 

[rwreuter]

http://www.ultimategarageheater.com/garage-heater-calculator.php

 

[DZL JIM]

Great, thanks for the links.