Heat Pumps in Colorado: Do They Actually Work Below Zero?

Ten years ago the honest answer was “not really.” A standard heat pump lost most of its capacity around 25°F and switched to expensive electric resistance heat. Today’s cold-climate models are a different product, and Denver has become one of the better places in the country to own one.

What changed

Variable-speed compressors and better refrigerant management let modern cold-climate heat pumps deliver full rated capacity down to about 5°F and keep producing useful heat below -10°F. The industry benchmark is the NEEP cold-climate list; if a model isn’t on it, it isn’t what we’re talking about here.

Denver’s winter is friendlier than you think

Denver averages fewer than a dozen nights a year below 0°F. Most of the heating season is cold nights and sunny 35 to 50°F days, which is exactly the range where a heat pump is at its most efficient, moving three or four units of heat for every unit of electricity it uses. A gas furnace, no matter how good, tops out at one unit of heat for every unit of gas it burns.

Dual-fuel: the setup we recommend most

Keep your gas furnace. Add a heat pump on top. A smart thermostat runs the heat pump whenever it’s the cheaper source and hands off to the furnace when the outdoor temperature drops below a switchover point we set for your utility rates, usually somewhere between 15 and 25°F.

You get:

• Efficient air conditioning in summer (a heat pump is an AC that also runs in reverse)
• Cheap heating for most of the winter
• Your furnace as backup for the coldest nights and as insurance if the power grid has a bad day

The money part

Between Xcel Energy rebates and Colorado’s state heat pump tax credit, a large chunk of the cost difference between a plain AC replacement and a heat pump can come back to you. The exact figures change year to year, so we put the current numbers, after rebates, on every written estimate next to the monthly financing payment. See our financing and rebates page for the programs we file for.

When a heat pump is the wrong call

• Your home has no ductwork and you don’t want ductless heads on the walls
• Your electrical panel is full and an upgrade isn’t in the budget
• You’re planning to move within two years

We’ll tell you if you’re in one of those buckets. Selling a heat pump to someone who won’t benefit is exactly the kind of upsell we started this company to avoid.