Do heat pumps work in Utah winters?

HVAC tips for Utah homes

We get this question a lot. People have heard heat pumps are efficient. They've also heard heat pumps don't work when it's cold. Both used to be fair. The first is still true. The second is much less true than it was.

Here's how heat pumps fit Salt Lake Valley homes today.

How a heat pump works

A heat pump is an air conditioner that can run in reverse. In summer it moves heat from inside your house to outside. In winter it pulls heat from the outdoor air and moves it inside. Even cold air holds some heat, and the heat pump concentrates it.

Because it moves heat instead of making it by burning fuel or running electric coils, a heat pump can deliver more heat energy than the electricity it uses. That's where the efficiency comes from.

The catch: the colder it gets outside, the harder the heat pump works to pull heat out of the air. Both its output and its efficiency drop as the temperature falls.

What's changed: cold-climate heat pumps

Older heat pumps lost a lot of capacity once temperatures dropped below freezing. That's where their reputation came from.

Newer cold-climate models use variable-speed compressors and better refrigerant controls. They hold much more of their heating capacity in cold weather and keep running at temperatures that would have shut down older units. ENERGY STAR has a cold-climate designation for heat pumps that meet stricter low-temperature requirements. It's a good place to start when comparing models.

Salt Lake Valley winters are cold, but most days aren't extreme. Valley lows often sit in the 20s, with colder snaps now and then. That's a range where a well-chosen cold-climate heat pump can carry most or all of a home's heating. Homes on the benches or up the canyons see colder nights, and sizing needs to account for that.

What about the coldest nights?

Every heat pump system needs a plan for the coldest stretch of winter. There are two common approaches.

Electric backup heat

Many heat pump air handlers include electric heat strips. They kick in when the heat pump can't keep up. They work, but they're the most expensive way to heat with electricity. If they run a lot, your power bill will show it. A properly sized cold-climate heat pump keeps backup use low.

Dual fuel: heat pump plus gas furnace

Most valley homes already have natural gas. A dual-fuel system pairs a heat pump with a gas furnace. The heat pump handles heating on milder days and all your cooling in summer. When it gets cold enough, the system switches over to the furnace.

The switchover point can be set based on comfort and on what gas and electricity cost at the time. It's a flexible setup, and it's a natural fit when your AC is due for replacement and your furnace still has years left. The heat pump takes the place of the AC, and you get efficient heating for much of the season without giving up gas heat on the coldest nights.

Defrost is normal

In winter, frost builds up on the outdoor coil. The heat pump periodically runs a defrost cycle to melt it. You may see steam rising from the unit or hear a whoosh when it switches. That's normal. What's not normal is the unit staying covered in thick ice for hours. That needs a service call.

Place the outdoor unit where it won't get buried by snow or dripped on by a roof edge, and raise it off the ground on a stand or pad. Meltwater needs somewhere to go.

Mini-splits for additions and problem rooms

Ductless mini-splits are heat pumps too. They have an outdoor unit and one or more slim indoor heads mounted on a wall or ceiling. No ductwork needed.

They're a strong fit for:

• Home additions and finished basements where running new ducts is hard
• Garages turned into shops or gyms
• Bonus rooms over garages that are always too hot or too cold
• Older homes without ductwork

Many mini-splits are rated for cold-climate use, and each room gets its own temperature control. See our mini-split installation page for more.

Is a heat pump right for your home?

It depends on a few things:

• Your current equipment. If your AC is old and your furnace is newer, dual fuel is often the easy path. If both are near the end, you have more options.
• Your ductwork. Heat pumps often deliver air that feels less hot than a gas furnace, over longer run times. Ducts need to be sized and sealed well for that. See ductwork services.
• Your house. Insulation, windows and air leaks all affect how much heat you need. A proper load calculation matters more with a heat pump than with a furnace.
• Your electrical panel. Some homes need electrical upgrades for a heat pump with backup heat.
• Rebates. Utility and government incentives for heat pumps change often. Check with your utility for what's available now.

When to call a pro

Call if you're planning to replace your AC or furnace and want to know whether a heat pump or dual-fuel system makes sense. We'll look at your house and equipment and give you a straight answer, including when it doesn't make sense.

If you already have a heat pump, call if it's blowing cool air for long stretches, the outdoor unit stays iced over, the backup heat seems to run constantly, or your winter power bill jumps without explanation. Our heat pump repair page covers those problems. For new systems, see heat pump installation. If you're trying to decide whether to fix what you have or replace it, try our repair-or-replace tool.