1.5t Goodman Heat Strip Sizing

[brianslink]

Trying to get correct heat strip sizing for Goodman 1.5 ton 15 Seer Heat Pump system for new construction 900 square foot home in NE Oklahoma. All electric home. Heat Load Load Calculation results:
16261 btu Heat Loss
11000 btu Heat Gain
15000 btu Actual House Distribution.

[BigJon3475]

Ummm......you don't know the watt to btu conversion?


Your HVAC contractor should know that one pretty easily.

[brianslink]

I've had 2 different contractors come on site and give me 2 different opinions on heat strip sizes...just trying to get more advice here...thanks for answering a question with a question.

[BigJon3475]

What did your contractors offer? And what was the reasoning behind their choices.



Sorry it kinda sounded DIY'er to me which is against the rules.

[brianslink]

One tech said 5kw and the other said 7.5kw for a faster recovery. I don't know anything about it really. DIY is out of the question because I don't really know enough about this stuff to try and tackle it myself..If I did I would not be asking the questiom, but thanks for flattering me. Antone else want to try and help?

[beenthere]

Ductwork in unconditioned space, 7.5KW
Ductwork in conditioned space, 5KW

[BigJon3475]

You'll learn if you keep coming here the more info supplied the better and more informative answer you'll get. Welcome to the site sorry to make it a poor experience.

Beenthere is the one to listen to.

[everythingair]

We simply don't know your circumstances well enough to make a really informed decision for you. Since there are 3,413 Btu's per KW of electric resistance heat at 240 volts input of electricity, a 5KW heater would provide about 17,000 Btu of heat which is more then your total estimated heat loss. Therefore, you should never need more then a 5kw heater if you are operating at 240 volts of electrical current.

[beenthere]

Therefore, you should never need more then a 5kw heater if you are operating at 240 volts of electrical current.

What if his ductwork is in unconditioned space???

[brianslink]

The ductwork will be in the attic.

[beenthere]

Then you will need to allow for the heat that the duct will lose in the attic. Depending on the amount of duct, its insulation, and the temp in the attic. You could lose 1800 plus BTUs. So a 5 KW won't be enough to heat the house if the heat pump were to break down at outdoor design temp.
But a 7.5 can.