is air source good chose for heating in NYC

[zygote nyc]

Hi everyone,

I'm new to this and want to know if someone can answer my question. I'm in the process of renovate my house. It's has two level total of 2200 sqft. I'm going to put in the mini split system. I have been told that it's not a good idea to use them heating in NY due to it low temperature. With all the advancement in air source heat plumps like Fujitsu 9/12RLS. Does it make sense to use air source heat plumps to heat my home instead of the gas water heat?

thanks everyone.

[Bigfreeze]

Are you in the city or the state? If you have the space install a ground loop as your average air temps throughout the heating season are very low. They use ASHP in switzerland extensively with similar temps but with energy prices in the US the way they are I'd be more inclined to go to gas than an ASHP

[zygote nyc]

I live in the suburb of New york city. I have a very small back yard 20x15ft. i don't know if it will be enough for ground loop. I don't know any one does geotherm in my area.

[Bigfreeze]

You could use a borehole system if you could get the rig to access the back of your house. An ASHP in NY would probably run an average COP of about 2-2.5 in the winter if running a low temp heating system.
Depending on the cost of electricity in NY you can work out the heat load of the house and whether the bills were something you would consider acceptable

[zygote nyc]

Bigfreeze,

I was not able to locate any local install that will do the borehole system BUt I'll continue to look in the mean time.

As for the heat load, can you tell me if there a simple way to do the calculation? rate is currently around .30 KW.

Thanks.

[Bigfreeze]

What are you using for heating at the moment? You can use your usage there to determine your annual heatlosses. PM me and I'll run through it with you

[dougheret0]

Air source heat pumps are rated at two outdoor temperatures, 17F and 47F. I doubt if any ASHP can effectively heat when OAT is less than 5F. At 17F, COP is 2-2.5, which is less efficient than gas when accounting for the source of the electricity. Also, cost per million BTU will usually be higher.

At low outdoor temperatures, heat pumps circulate "cool" air. That is, air warm enough to heat the space, but often only 85 - 90F, which when swirling around in a room, will feel drafty, especially to older people. This can be helped with electric "auxilliary heat", which is needed anyway for the defrost cycle. The rated COP includes an allowance for defrost, but not for operating with the heat pump in heat mode.

In my opinion, natural gas always trumps heat pumps. However, in climates where temperatures below 20F are rare, heat pumps work fine and are simpler and cheaper than gas furnaces. If I lived north of the Mason-Dixon, I would want gas or hydronic heat.