Furnaces have a BTU's input rating, for simplicity lets say 100,000 BTU's and it is a 95% furnace, then we multiply the 100,000 BTU's X 0.95 and get 95,000 BTU's output. If you measure the BTU's after finding how much air the unit is moving and multiplying that by 1.08 X Temp rise between the supply and return it should come out close to what it is rated for.
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great job
Thank you this will help me out in the field
Your welcome
Question: If you had a 90% Furnace would you had to multiply 45,000 x .90 ?
Or where did you get the .80 from?
Thanks, I loved your video!!
Furnaces have a BTU's input rating, for simplicity lets say 100,000 BTU's and it is a 95% furnace, then we multiply the 100,000 BTU's X 0.95 and get 95,000 BTU's output. If you measure the BTU's after finding how much air the unit is moving and multiplying that by 1.08 X Temp rise between the supply and return it should come out close to what it is rated for.