Performance data

[help3]

I need 42,000 btu for heating, the specs on my unit says is will produce 29,700 btu@47 degrees and 17,600 @17 degrees. Will I ever be able to reach 72 degrees without back up heat?

[hot wired]

it depends on the place u live? I dont think u want to undersize a ?

[cem-bsee]

probably reach 72F when 65F outside --

so, insulate, caulk, --- +

[ct2]

It will heat a dog house to 72 degrees , well a small dog house----but not when its below zero----

[docholiday]

Whats the temp that you need 42,000? Is that zero or -5 degrees? Heat pumps are sized for cooling. My guess until I see an answer is yes you will need aux heat but you should have a fairly low balance point.

Whats your load calc say you need for heat at 47? Whats your load calc say you need for 17?

[help3]

I'm new to this HVAC stuff, what is a balance point?
Do they size the unit to a outside tempature?

[beenthere]

Balance point is the outdoor temp that if the temp gets any lower the heat pump won't provide enough heat by itseld to heat the house.
So you will need some back up heat.

Yout heat pump is sized for the cooling load, not heating load.

[docholiday]

Your 42,000 is the total amount of heat needed when its at the coldest outside, lets say 0 degrees depending on where you live. This is the amount of electric heat needed as back up heat. The balance point is the point where the amount of heat loss from the structure equals the amount of heating capacity from your heat pump without the electric heat. Any lower and the aux heat will need to cycle on occasionally and supliment the difference.

More often than not you will be above the balance point as it generally doesnt stay that cold for weeks on end. If you are however in Alaska or Canada, that may not be the case.