A broken heat pump can leave your home too hot in summer or too cold in winter, and because a heat pump handles both heating and cooling, you feel the problem right away.

The good news: some heat pump problems have simple fixes you can safely check yourself in a few minutes. Others involve refrigerant, high-voltage electrical parts, or major components that need a licensed technician. This guide walks you through fixing a heat pump step by step, explains what common symptoms mean, and shows you when it is time to call for help.

Can You Fix a Heat Pump Yourself? The Short Answer

You can fix some heat pump problems yourself, like wrong thermostat settings, a dirty air filter, a tripped breaker, or debris blocking the outdoor unit. But refrigerant leaks, electrical failures, bad capacitors, compressor problems, and reversing valve issues need a licensed HVAC technician. If your heat pump is still broken after basic checks, or you notice burning smells, ice that will not melt, or repeated breaker trips, turn it off and call a professional.

Heat Pump Broken? Start With These 7 Safe Checks

1.         Check the thermostat mode. Make sure it is set to Heat or Cool, not Off or Fan Only, and that the temperature setting is higher (for heat) or lower (for cooling) than the current room temperature.
2.         Check thermostat power. Replace batteries if your thermostat uses them. If the screen is blank, check its breaker.
3.         Replace a dirty air filter. A clogged filter can cause poor airflow, frozen coils, and system shutdowns.
4.         Check the breakers. Heat pumps often have separate breakers for the outdoor unit and the indoor air handler. Reset a tripped breaker once. If it trips again, leave it off and call a technician.
5.         Check the outdoor disconnect switch. Many outdoor units have a shut-off switch nearby. Make sure it is on.
6.         Clear the outdoor unit. Remove leaves, grass, and debris. Keep about 2 feet of open space around it.
7.         Wait a few minutes. After a power reset or thermostat change, many heat pumps have a built-in delay before the compressor restarts. Give it about 5 minutes before assuming it is broken.

If your heat pump still is not working, use the troubleshooting guide below.

Heat Pump Troubleshooting by Symptom

Problem	Common Causes	DIY Check	Call a Pro If…
Heat pump will not turn on	Thermostat settings, tripped breaker, failed capacitor, control board	Thermostat, breakers, disconnect switch	Breaker trips again or unit hums but will not start
Blowing cold air in heat mode	Defrost cycle, thermostat setting, reversing valve, low refrigerant	Wait 10 minutes; confirm Heat mode	Cold air continues
Not cooling in summer	Dirty filter, dirty coil, low refrigerant, reversing valve stuck	Filter, outdoor unit clearance	Warm air continues after filter change
Ice on the outdoor unit	Normal frost, failed defrost control, low refrigerant, blocked airflow	Watch if it melts during defrost	Thick ice stays for hours
Running constantly	Extreme weather, dirty filter, low refrigerant, leaky ducts, undersized system	Filter, thermostat setting	House does not reach set temperature
Short cycling	Thermostat problem, oversized system, low refrigerant, electrical issues	Thermostat location and settings	Keeps turning on and off quickly
“Aux Heat” on all the time	Large thermostat changes, heat pump not working, thermostat setup	Avoid big temperature jumps	Aux heat runs in mild weather
Indoor fan runs, outdoor unit does not	Tripped breaker, failed capacitor, contactor, compressor problem	Outdoor breaker and disconnect	Outdoor unit still does not start
Loud noises	Loose parts, motor problems, debris, electrical issues	Check for debris with power off	Grinding, screeching, or buzzing continues
Water leaking indoors	Clogged condensate drain, frozen coil	Filter; check for ice	Leak continues
Burning smell	Overheating motor, wiring, or heat strips	Turn system off	Always, unless it is a brief dusty smell on first use

Fixing a Heat Pump: Common Problems Explained

1. Heat pump will not turn on

Start with the thermostat, breakers, and outdoor disconnect switch. If the outdoor unit hums but the fan or compressor does not start, a failed capacitor is a common cause. Do not try to replace a capacitor yourself. Capacitors can hold a dangerous electrical charge even when the power is off.

2. Heat pump blowing cold air in heat mode

This is one of the most common heat pump complaints. Possible causes:

•             Defrost mode: in cold, damp weather, your heat pump briefly reverses to melt frost on the outdoor coil. You may feel cooler air for a few minutes. This is normal.
•             Normal heat pump air: heat pump air feels less hot than furnace air, even when it is working properly.
•             Thermostat wiring: if you recently installed a new thermostat and your system cools when set to heat, the thermostat may be wired or set up for the wrong type of system.
•             Reversing valve problem: this part switches the system between heating and cooling. If it sticks, the system may heat when it should cool or cool when it should heat.
•             Low refrigerant: usually caused by a leak.

3. Heat pump not cooling

Check the filter and outdoor unit first. If the air is still warm, the cause may be dirty coils, a refrigerant leak, a failed capacitor or fan motor, or a reversing valve stuck in heating mode.

4. Ice on the heat pump

Light frost in winter is normal, and the defrost cycle should melt it. Heavy ice that covers the coil for hours is not normal. It can mean a failed defrost control, low refrigerant, a bad outdoor fan motor, or blocked airflow.

What to do: switch the thermostat to Emergency Heat if you need heat, and call for service. Never chip ice off the coil, which can damage it.

In summer, ice on refrigerant lines or the indoor unit usually means poor airflow or low refrigerant. Turn the system off, replace a dirty filter, and let it thaw.

5. Heat pump running constantly

On very hot or very cold days, long run times can be normal. If the house never reaches your set temperature, have the system checked for low refrigerant, dirty coils, leaky ducts, or a failing component.

6. Aux heat running too much

Auxiliary heat uses electric heat strips, which cost much more to run than the heat pump. It is normal for it to turn on during defrost or very cold weather. If it runs often on mild days, the heat pump may not be heating properly, or your thermostat settings may need adjustment.

7. Strange noises or smells

Grinding, screeching, loud buzzing, or burning smells should be checked right away. A light dusty smell the first time you use heat each season is normal and should fade quickly. For more help with odors, read heat pump odors you should not ignore.

When to Use Emergency Heat

If your heat pump stops heating in winter, you can switch your thermostat to Emergency Heat (EM Heat). This turns off the heat pump and uses only the backup heat strips.

•             Use it only until a technician can repair the heat pump.
•             Expect higher electric bills while it is on.
•             If Emergency Heat does not work either, turn the system off and call for service.

What Not to Do When Fixing a Heat Pump

•             Do not open electrical panels or touch wiring.
•             Do not replace capacitors, contactors, or control boards yourself.
•             Do not add refrigerant. Handling refrigerant requires EPA certification, and low refrigerant means there is a leak.
•             Do not chip or scrape ice off the coils.
•             Do not keep resetting a breaker that trips repeatedly.
•             Do not use a pressure washer on the outdoor coil.

Attempting advanced repairs can void your warranty, damage the system, and create serious safety risks.

What Happens During a Professional Heat Pump Repair

1.         Inspection. The technician checks the indoor and outdoor units, thermostat, and breakers.
2.         Diagnosis. They test electrical parts, refrigerant pressures, airflow, defrost controls, and the reversing valve.
3.         Explanation and pricing. You should get a clear explanation of the problem and the price before any work begins.
4.         Repair. The technician replaces or repairs the failed part.
5.         Testing. The system is tested in both heating and cooling modes to make sure it works properly.

Wondering what repairs cost? See our guide to AC and heat pump service costs.

Common Heat Pump Repairs

•             Capacitor or contactor replacement
•             Outdoor fan motor or blower motor repair
•             Refrigerant leak repair and recharge
•             Reversing valve repair or replacement
•             Defrost control board or sensor replacement
•             Thermostat repair, replacement, or setup
•             Condensate drain clearing
•             Backup heat strip or sequencer repair
•             Compressor repair or replacement

Why Heat Pumps Break Down in Houston-Area Homes

•             Year-round use. Heat pumps here cool for most of the year and heat in winter, so parts wear faster.
•             Extreme summer heat puts stress on capacitors, motors, and compressors.
•             High humidity leads to clogged drain lines and frozen coils when airflow is poor.
•             Sudden cold fronts can expose weak defrost controls and backup heat problems.
•             Storms and power surges can damage electrical components and control boards.

Get ready for both seasons with our seasonal HVAC checklist for Houston’s extreme weather.

Why You Should Not Wait to Fix a Heat Pump

A heat pump that is struggling usually uses more energy and puts extra strain on its most expensive parts. A small problem like a weak capacitor or low airflow can lead to a compressor failure if ignored. Learn more about the hidden costs of delaying repairs.

Repair or Replace Your Heat Pump?

Repair is usually the right choice for newer systems and smaller problems. Replacement may make more sense if:

•             Your heat pump is around 10 to 15 years old or older
•             It needs a major repair, like a compressor or reversing valve, and is out of warranty
•             It uses R-22 refrigerant
•             Repairs are becoming frequent
•             Energy bills stay high even after repairs

For help deciding, read our repair vs replace guide. If you are considering a new system, see the pros and cons of heat pumps.

How to Prevent Heat Pump Problems

•             Schedule professional service twice a year, before summer and before winter.
•             Change your air filter every 1 to 3 months.
•             Keep the outdoor unit clear of debris.
•             Avoid large thermostat changes in winter.
•             Consider surge protection for your system.
•             Have leaky ducts checked. Duct sealing can improve airflow and comfort.

See our full heat pump maintenance checklist. You can also learn how smart thermostats improve comfort and cut energy bills.

Heat Pump Repair in Houston and Spring, TX

When your heat pump is broken, KAC Express can diagnose the problem, explain your options, and get your home comfortable again. We provide heat pump repair, maintenance, and installation throughout the Houston area, including Spring, The Woodlands, Klein, Tomball, Humble, and nearby communities.

•             Licensed Texas HVAC contractor (TACLB33125E)
•             Open 7 days a week, 7am–10pm
•             Same-day or next-day appointments available
•             New customer special: $50 off your first repair
•             400+ Google reviews from local homeowners
•             Financing available

Real customer feedback: One recent Google reviewer shared that a KAC technician came out late at night and fixed their system.

Need to fix a heat pump? Call KAC Express at 832-326-5687 or schedule service online.

Frequently Asked Questions

How do I reset my heat pump?

Turn the system off at the thermostat, switch off the breakers for the indoor and outdoor units for about a minute, then turn them back on. Set the thermostat again and wait about 5 minutes. If the breaker trips again, do not keep resetting it.

Why is my heat pump blowing cold air in heat mode?

It may be in a normal defrost cycle. If cold air continues for more than a few minutes, the cause could be thermostat settings, a stuck reversing valve, or low refrigerant.

Why is my heat pump not turning on?

Check the thermostat, breakers, and outdoor disconnect switch. If those are fine, a failed capacitor, contactor, or control board may be the problem.

Is it safe to run a broken heat pump?

It is not recommended. Running a heat pump with a problem can cause more damage. Use Emergency Heat for warmth if needed, and call for repair.

How long does heat pump repair take?

Many common repairs can be completed in a single visit. Larger repairs, like a compressor or reversing valve replacement, can take longer and may depend on part availability.

Can a heat pump be fixed, or does it need replacing?

Most heat pump problems can be repaired. Replacement usually makes more sense for older systems with major failures, R-22 refrigerant, or frequent breakdowns.

Why does my heat pump keep freezing up?

Common causes include a dirty air filter, low refrigerant, a failed defrost control, or a bad outdoor fan motor. A technician should diagnose repeated freezing.