I have very old Gas furnace:
LENNOX gas furnace
Model: G20Q3/4E-100-3
Made on year 1990
The Furnace capacity =100,000 Btu/hr.
My house is 30 yrs old, 2008 square feet.
I got the gas usage 263 ccf during 41 days from 02/24/11 to 04/06/11. The total heating degree days were 1183 during this period. The house inside temp was about 67 F.
Does anyone know how to calculate daily actual output from the furnace? Is there any equation for my reference.
Thank you in advance!