Heil Furnace Replacement - http://www.hvacmechanic.com/ Forums

Original message

JCMSr

166.82.228.12

"Heil Furnace Replacement" , posted Mon 21 Apr 17:53

I currently have a Heil Model PGAD47F1K3 package unit which needs replacing. The original unit was manufactured in 3/96. It is a 4 ton unit with a 135,000 BTU furnace. Without knowing the efficiency rating of the old unit (or SEER rating) I am unsure of what size the new unit needs to be. Assume the new unit to be a minimum 13 SEER. This unit needs to service a home of approximately 2500 sf with 9'+ ceilings in the Charlotte, NC area. I am OK with the AC side but am being told that I can reduce the furnace to 115,000 to 120,000 BTU's with no problem. Does this sound right?

Thanks

Replies:

smythers1968

66.232.220.95

"Re(1):Heil Furnace Replacement" , posted Mon 21 Apr 19:04

If the existing furnace is 80% or less and you are replacing it with a 90% I would say yes.

OLD
135K X .80 = 108K btu into house

NEW
120K X .90 = 108K btu into house
115K X .90 = 103.5K btu into house
120K X .80 = 96K btu into house - Might be ok but I don't know your climate.

Good luck

Life lesson #12 Know when not to do it yourself.
WOW That Can Hurt!!

JCMSr

166.82.228.12

"Re(2):Heil Furnace Replacement" , posted Mon 21 Apr 20:39

Here's a little more information I discovered after my OP. The existing furnaces' output is actually 106,000 which is approximately 78.5% efficiency. Assuming the new unit operates at 80% efficiency the output would only be 96,000. I have been told that nobody currently makes a package unit with better than 80% efficiency. That would be roughly a 10% reduction in the BTU output and that gives me some cause for concern. Am I over reacting?

smythers1968

66.232.220.95

"Re(3):Heil Furnace Replacement" , posted Mon 21 Apr 20:53

I don't think there is a big concern.

I would look into a 2 or 3 stage heat package unit.

Life lesson #12 Know when not to do it yourself.
WOW That Can Hurt!!