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0 pointssnozolli3y ago0 comments

With a heat pump, you -need- an alternative source of heat - since some days when it's particularly cold

Modern heat pumps redirect some heat to prevent the coils from freezing. What you wrote is common FUD pushed by the oil & gas companies.

That said, you'd be a fool to live in an area with life-threateningly low temperatures and not have a backup heat source.

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4 comments · 2 top-level

pandaman3y ago· 2 in thread

"Redirect some heat" from where? In the installs I've seen they did it from inside the house i.e. literally cooled the house down. The alternative heat is needed to keep the inside temperature up and work against the pump cooling your house down when it's already cold. Do you have some other alternative source of heat on the modern heat pumps?

snozolliOP3y ago

"Redirect some heat" from where?

What part of redirect is confusing?

In the installs I've seen they did it from inside the house i.e. literally cooled the house down.

Cooled the house down, or simply warmed it less than would be possible otherwise, assuming that magic prevented freezing of the coils?

I'll take a reduction in efficiency over a complete lack of function.

pandaman3y ago

>What part of redirect is confusing?

Your whole argument is. Heat pumps need a secondary heat source because at the temperatures around 0C they accumulate ice on the heat exchanger outside. To melt the ice they reverse the energy flow so they cool the house and heat that heat exchanger. You asserted that it's just FUD and they can "redirect some heat" instead. This implies they don't cool inside and instead redirect heat from elsewhere (second outside heat exchanger perhaps?).

But it appears there is no second heat exchanger outside and the modern heat pumps work just like heat pumps from couple years ago.

As for keeping the functionality - it's a philosophical question. For me personally, if I turned on the heater because it's cold inside and it started blasting cold air, I'd call the repair people immediately. While it still works in the sense that it makes noise and consumes energy, it stopped performing its function of heating so I'd consider it lost the functionality I am interested in the most.

Casteil3y ago

>Modern heat pumps redirect some heat to prevent the coils from freezing. What you wrote is common FUD pushed by the oil & gas companies.

It's not FUD, and you COMPLETELY ignored & omitted the rest of my sentence from your quote. I'm well versed on how heat pumps work. I was not saying heat pumps don't work below freezing. Rather than simply repeat myself, let me rephrase:

1. Heat pump efficiency gets worse the closer you are to the minimum (outside) temperature they're rated down to.

2. Even with the best (and most expensive) technology, that means efficiency of these units approaches that of a $15 space heater.

3. When it gets TOO cold, they can stop working entirely if they don't have a resistive backup heat system (which, again, is effectively a $15 space heater you paid a lot more for).

Both Canada & the northern US experience these temperatures occasionally (-10f to -30f and worse on some occasions).

Hence the need for backup heat - e.g., a pellet or wood-burning stove, backup furnace running propane or natural gas, or even just something cheap and simple like a $150 portable diesel heater. You don't want to be left without heat in a multi-day power outage after a half inch of ice and high winds.

For backup heat, it's more efficient to burn whatever fuel for heat than run a generator outside to power space heaters or a heat pump at those brutally low temps that often follow those hard ice storms.

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