HI ,
Getting conflicting information about furnace replacement load…
I am looking for recommendations for a service that specializes in the residential heat load calculations. Preferably local to Lake County IL.
We currently have Armstrong SX80 Ultra, 150K BTU system. It is old and had some issues that were fixed, and we are looking for replacement.
AC: is Armstrong Air, m/n4AC13L48P-7A
We had 4 different contractors and all suggest to downgrade.
When I am asking based on what, the answers are anywhere from we enter your info and system suggested 83K BTU to 89K BTUs, the system was incorrectly installed, your system is over sized, and some even suggest broken HE. System is serviced somewhat regularly and when cleaning was done, everything looked ok. No one mentioned about HE. I am very confused.
From reading and youtube, I tried to see if my burners show any signs of air blowing, and did not see any irregularities.
Pilot lights up one, then the rest pick up and flame is not bursting outward…
I understand, it needs to be diagnosed, and looking inside is a must…
The furnace sits on floor and does have limited air flow, the filter box is on floor and it is 20x25x4 so 4 inches is blocked…
The furnace should be raised to add for needed airflow.
I am at the point of trying to understand what is the optimal system load I need to keep my house warm/comfortable.
I ran some basic calculations on what is available:
and here is what I get:
Zone 4, 40-50 BTUs/sq ft
total living area : 2600 sq ft
Based on this I get :
40×2600=104K BTU input; Getting 80% 110K BTU system will give me about 83,200BTU
50×2600=130k BTU input; Getting 80% output is 104K BTUs
My input is 150K and output is 120K BTU
The house has finished 750sq ft basement with fireplace… .
In addition, the ceiling on the 1st floor 8 feet, with open area of 21 feet. (cathedral ceilings)
Second floor rooms, have slanted ceilings, with some 13 feet going to 5 feet.
2 fireplaces and dual hung windows… insulation is not the best.
construction grade is average.
I am leaning towards 50×2600 calculations…. based on these factors(colder climate, average insulation, drafty windows, fireplaces)
Then I ran a more “thorough” if I may say that, calculation from load-calc using a Whole House Block Load, and I got 62K BTUs.
Before making a decision on what system to get, I need to understand what is the needed load for my house.
Am I on the right track here?
Should we just forget about it and go with 80% 2 stage 110K carrier?
I honestly, can’t imagine going from 150K BTU system to 110K BTU.
Here are the screenshots (hope they post ok)
Attachment 838747Attachment 838748
Any feedback is helpful,
Thanks a lot for all your inputs.