By Hood Service Company · Corsicana, TX · Updated
The short version
- One heat pump handles both cooling and heating by reversing the flow of refrigerant.
- It moves heat rather than burning fuel, which is why it's efficient in mild weather.
- Heating output drops as it gets colder, so most systems have backup heat for hard freezes.
- Light frost and short defrost cycles in winter are normal; a unit encased in ice is not.
What is a heat pump?
A heat pump is a heating and cooling system that moves heat with refrigerant, just as an air conditioner does, but with a reversing valve that lets it run in either direction.
In a typical split system, the outdoor unit looks like an AC condenser, and an indoor air handler holds the coil and blower. Because one heat pump covers both seasons, there's no separate furnace unless you choose a dual-fuel setup.
How does a heat pump heat your home in winter?
In heating mode, the outdoor coil becomes the cold side. Refrigerant absorbs heat from the outdoor air, which holds usable heat even when it feels cold, and the compressor delivers that heat to the indoor coil.
Because it moves heat instead of making it, a heat pump can deliver more heat energy than the electricity it uses, especially in mild weather. As outdoor temperatures fall, there's less heat to collect and the system works harder, so its output and efficiency drop.
Why do heat pumps suit North-Central Texas?
Long, hot summers make cooling the main job here, and winters are mostly mild with occasional hard freezes. A heat pump handles the cooling and can cover most heating days efficiently.
That's a good match for the climate, but the occasional deep cold snap still matters. Plan for backup heat, and make sure the system is sized for both seasons. Our guide to HVAC sizing and load calculations explains how that's done.
What happens during a hard freeze?
On the coldest days, a heat pump may not keep up on its own. Backup heat, either electric heat strips in the air handler or a gas furnace in a dual-fuel system, fills the gap automatically.
Your thermostat may show 'aux heat' when backup heat is helping. That's normal in a freeze, but backup heat uses more electricity, so aux heat that runs on mild days is worth a service call. A hybrid system pairs a heat pump with a gas furnace and switches between them as the weather changes.
Emergency heat is a manual thermostat setting that runs backup heat only. Use it if the outdoor unit has stopped working, not as an everyday setting. Frost on the outdoor coil is handled by short defrost cycles; our guide to heat pump icing and defrost explains what's normal.
What efficiency ratings apply to heat pumps?
Heat pumps carry two ratings: SEER2 for cooling and HSPF2 for heating. Under DOE minimums that took effect January 1, 2023, new split heat pumps must reach at least 14.3 SEER2 and 7.5 HSPF2.
Higher numbers mean less electricity for the same comfort, but installation quality matters as much as the label. Our SEER2 ratings guide explains the scale, and the SEER calculator lets you compare ratings using your own usage.
How do you keep a heat pump working well?
Because it runs in both seasons, a heat pump logs more hours than an AC that only cools. A spring and a fall tune-up, plus regular filter changes, keep it efficient and catch problems early.
Keep the outdoor unit clear of leaves and debris, and don't let gutters drip onto it. Every Hood Comfort Club tier includes spring and fall tune-ups; see our maintenance plans. To learn more, visit our heat pump services page.
When should you call a technician?
- Aux or emergency heat runs for long stretches on mild days.
- The outdoor unit stays coated in ice for hours.
- The vents blow cool air while the thermostat calls for heat.
- The system won't switch between heating and cooling.
- You hear grinding, rattling or screeching from the outdoor unit.
Frequently asked questions
Why does heat pump air feel cooler than furnace air?
A heat pump typically delivers air that's warm but not as hot as air from a gas furnace, and it runs longer cycles to make up the difference. The house still reaches the set temperature. Air that feels cool rather than mildly warm may point to a problem.
Should I turn a heat pump way down at night in winter?
Large setbacks can backfire, because bringing the temperature back up in the morning may call on backup heat. Small setbacks, or a thermostat designed for heat pumps, avoid that. Ask your technician what suits your system.
Is steam from the outdoor unit in winter normal?
Usually, yes. It's typically the defrost cycle melting frost off the outdoor coil, and it stops within a few minutes. Smoke with a burning smell is different; turn the system off and call.
Do I need a separate air conditioner with a heat pump?
No. A heat pump cools the same way a central air conditioner does in summer. That's one reason it's a popular choice where cooling is the main job.