Heat Pump Capacity

[Kaytusk]

I am putting in two new rooms about 200 sq ft each, making my house a 2100 sq ft house. Will a 3 1/2 ton heat pump be able to provide the necessary heat/cooling?

[TigerDunes]

Kaytusk

There is no way to answer this question without having a Manual J heat/cool load calculation performed by a reputable dealer. The Manual J is a software program used by professional dealers in properly sizing equipment. The Manual J takes into consideration the individual characteristics of your home including size, floorplan,number of windows, insulation properties, number of persons living in home, climate of area of country, and individual comfort level.

:)

[mattison]

On a hot day how does your current a/c function? Does it cyle at all?

[Kaytusk]

The heat pump seems to work effectyively on a hot day (mid-90's).
Winter weather is about mid 20's.

I understand that there are ways to measure this, but I was just looking for the 80% answer. I was also wondering if additional insulation on the new addition would help?

[TigerDunes]

Kaytusk

I am making assumption your home is single story even with the additions.
Correct?

Insulation should be to code overhead in attic, in walls, underneath in crawl space, DP windows. I would also review your attic ventilation.

I am not certain what 80% means-are you speaking of probability that existing system will take care of addition?

[Kaytusk]

Single story.. yes. 4 BR, 2 bathrooms, living, dining, eat-in kitchen, and familiy rooms, small laundry room.
Insulation... I am planning to exceed code, is there value added in doing so (i.e., 3x6 constructions and ventilation vice 2x4)?

80% answer refers to the odds that a 3 1/2 ton will heat/cool 2100 sq ft.

[Ed Imeduc]

Like said you have to run a heatloss and AC load to know if it will work. Just off hand 3.5 ton should do 2100sq ft ok.But you dont even say where you are. More insulation pays for sure .Also good vents in thr attic 1/2 in, in the over hang amd 1/2 out. A power vent fan on a tstat pays also up there.

ED ;)

[TigerDunes]

Kaytusk

If I was a betting person, I would say less than 50/50. Cooling on hot days will be your troublespot. Your comfort level on those very hot days will just not be the same as it is now. No way.It is possible though to do some things to lower your cooling load with improved insulation techniques at doors, windows, attic ventilation, etc. You can compensate on the heating side with a larger KW heat strip. I wouldn't even do that though without first seeing how unit performs on those very cold days.

My opinion.
Good Luck!
:)