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.
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.