Outdoor Wood Boiler BTU Load Calculator     

The easiest and best way to establish your BTU requirement
is to look at your current furnace.

There is normally a label on the furnace that tells you the BTU output.
If your furnace is 90% efficient, you may have to multiply that amount by 0.90.
If not, call the manufacturer or go to their website with your
model number and they will tell you the rating. 

Any furnace rated at 180,000 BTU NET output or less, can be generally be replaced with our Hyprotherm 185, assuming that it heats your home well now.

Of course if a furnace is oversized (e.g 100,000) and can really heat your home with 50,000 BTU, then that should be considered and we recommend it because you will load it half as much, as little as ONCE A DAY!

 There is no such thing as a furnace that is too big because it is not like an air conditioner, where if you get one too big, it becomes inefficient.

This is like getting a bigger propane or oil tank!  You can load it with more wood (full rounds - no splitting!) and it will burn longer and therefore you will load it less often. No one has ever complained and said that I sold them one too big. In contrast, many people have said, "I wished that I listened to you!"

 Use square footage estimates below. 

The Hyprotherm 100 STORES 100,000 BTU, ready for immediate use, unlike others who give you phony numbers of what a furnace can do at maximum output, which may be 20 minutes.

Also remember, that the home should be no bigger than the rated  square footage of the boiler, unless in a southern climate like us in AR or in NC or further south. See listings HERE

But remember, it's more critical to have a heat exchanger with the correct output or bigger. If the heat exchanger is too small, you will never get enough heat, no matter how big the furnace is!

Select Insulation Type Little or No Insulation Poor Average Good Climate/Region Very Cold-NH, NY, Ohio Cold-PA Temperate-VA, WV, AR Moderate-NC-TN Square footage to heat x Ceiling height (feet) ===>   BTU     (Watts )