Heat pump in climate zone 5
I recently completed a manual J via the coolcalc software. I am in climate zone 5. I am installing the equiptment in a conditioned attic space. This unit will only serve the newly constructed 2nd Floor. My wall assembly is an R26 with a cathedralized attic ceiling of R50. My windows are triple pane Double lo-e with argon U value .19 & SHGC . 36. I have 1100sf of floor space and approx. 13k cubic sq ft including conditioned attic space. Coolcalc Software is giving me 40k +\- Heating BTU’S & 20K+\- Cooling BTU’S .
So my question is does a heat pump make sense in my climate? Natural gas is still pretty cheap around here but I would at some point in the future like to include a grid tied solar array. I have looked at a goodman hybrid system that has a condensing furnace as backup since the heat pump is rated for down to -5f. We do have a handful of days that it can dip below this. Based on my cooling demand a 16 seer 2ton heat pump would produce 24k heating btu’s i believe. This would work well i think if the temp stays 40f and above which is also the temp the efficiency of the heat pump would begin to degrade.
I am also torn on sizing of the condensing furnace. There is a 2 stage 96% 40k btu or a modulating 98% 60k btu. The modulating version can modulate the gas valve down to a low fire output of 29k btu.
Given the numbers and application would skipping the heat pump all together and investing the money into an 18seer 2ton 2 stage a/c condensor be a wiser investment.
I have be happy with the price point of goodman and have had good experience with them so it was my go to. However i am not opposed to change.
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