The Need for Electric Heat Strips in a Heat Pump
Nola_Sweats
| Posted in General Questions on
If the Minnesota guy doesn’t use his auxiliary electric heat strips (www.greenbuildingadvisor.com/article/do-heat-pumps-work-in-minnesota), do I even need to install them in New Orleans? This is less about the $75-ish cost of the heating filament and more about how quickly even a 4.5kw heat strip would drain a battery backup system.
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For you, the only reason to have them is that if you have a mechanical failure of your heat pump--in the compressor or perhaps a refrigerant leak--the heat strips could, at high electric cost, keep the house warm while you wait for service. But they can also kick in automatically by mistake, using lots of energy without you knowing, if there's a control failure. I would either install them and leave the circuit breaker off, requiring a manual action on your part to activate them in an emergency, or omit them.
Thanks. I hadn't thought of the circuit breaker option, which would work fine. My Nest thermostat allows me to lock out auxiliary/emergency heat, but the new system would have a proprietary thermostat that might not have that as an option.
Just buy a space heater, and keep it in the closet. In Canada, in December I can keep my Pretty Good House warm with just two space heaters.
For comfort reason strip heat is often used for reheat of the system air during defrost cycles to avoid blowing cold-air out the registers. In some systems (like the Carrier Infinity GreenSpeed ) that can be turned off, but typically the default setting for those systems calls for re-heat during defrost, which takes a good chunk out of the as-used efficiency. In other systems it's hard wired for strip heat during defrost.
The installed cost of strip heat is more than the $75 for the strip heater itself. The higher amperage draw usually bumps up the wiring gauge (sometimes by quite a bit) and breaker size.
In New Orleans the heat loads are low enough that even the smallest strip heat options can be oversized, and having tepid-air output during defrost cycles probably isn't a significant comfort hit, but it's really up to you whether paying a bit more on the power bill for reheat during defrost cycles is "worth it".
We're in Seattle and have gotten by without heat strips so far. Thinking of putting them in, though. There are one or two weeks a year we get cold enough temps that the heat pump can't quite keep up. One year we were away and missed the worst of it, and last winter we were a bit chilly that week, but not too bad.