Best source of heat? Looking at ductless heat pumps
user-1101394| Posted inEnergy Efficiency and Durabilityon
I live in Long Beach, Ca., on the ocean. We never need AC, but need heat in the winter.
I removed our old furnace and duct work. Our top unit of duplex is approx. 1,700 sq. feet.
Are ductless heat pumps a good option? We have a wood/gas fireplace that heats main living/dining area. We would probably need two heat pumps. There is no attic. Older 1960s duplex.
THANK YOU for any feedback!
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Replies
Marianne,
If you have access to natural gas, that's probably the cheapest way to heat your house. One or two gas-fired space heaters with through-the-wall venting may be all you need. These units cost about $1,000 to $1,500 each, plus installation.
One or two ductless minisplit units could also be used; they cost about $3,000 each (installed cost). The advantage of the ductless minisplits: if global temperatures continue to rise in future years, you'll have the ability to air condition your house.
从舒适性的角度来看一个inverter-drive ductless will be more pleasant than a gas-fired wall furnace, and in a SoCal climate it may even be cheaper to operate- it really depends on your electrical and gas rates. The 99% heating design condition for Long Beach is +43F, a temperature at which better-class ductless will have a coefficient of performance (COP) better than 4, and your seasonal average may be close to 4.5.
If your power rates (all delivery charges included) are 15 cents/kwh and you averaged only a COP of 4 you get 4x 3412= 13648 BTU for $0.15. Normalized to BTU/$ that's 90,987 BTU/$
With an 82% efficient wall furnace and buck a therm gas you get( 0.82 x 100,000= ) 82,000/BTU/$
But if your rates are different, the analysis is different too. At your annualized average heat load there may be no economic argument for the more expensive ductless, but they're generally quieter and it's possible to sized them closer to your (fairly tiny) heat loads, whereas you may be overshooting at typical wall-heater outputs. A right-sized ductless will track the load, running nearly continuously at the lowest blower speed, for very even room temps, whereas wall furnaces are on/off heaters.
A third option would be a hydronic baseboard or panel heaters running off a condensing gas water heater, which would have lower operating costs than a wall furnace (and comparable to the ductless, if you have 15 cent electricity and buck-a-therm gas.)