Heat Pump Repair in St. Louis, MO

Frost on a heat pump is not automatically a problem, but ice that stays is. The unit melts its own frost through a defrost cycle, and repair is needed when that cycle fails or the system quits heating. A guide from the Center for Energy and Environment, hosted by the Department of Energy, says outdoor coils may frost below freezing but should clear themselves.

How do you tell normal frost from a failed defrost?

Normal frost comes and goes within a heating cycle, and failed defrost leaves the coil buried in ice. The Center for Energy and Environment guide lists the signs that a heat pump is not working properly:

• The unit is not running, or it cycles on and off frequently.
• The thermostat never reaches its setting.
• Auxiliary heat shows on the thermostat constantly.
• The indoor or outdoor coil is frozen.
• There is excessive noise, odd smells or high humidity.
• Your electric bill jumps without a cold snap to explain it.

During a normal defrost, the same guide says, meltwater drips from the unit and supplemental heat may run so the house does not go without. The water should drain away from walkways, where it can refreeze.

Why do heat pumps struggle in St. Louis winters?

A heat pump here works twice as hard as one in a place with a single season. St. Louis sits in Climate Zone 4A. The National Weather Service logged 4,100 heating degree days and also 1,904 cooling degree days in 2025, so one outdoor unit carries both loads. Reversing valves, contactors and fan motors see year-round duty.

Local conditions add stress:

• Freezing rain and thaw cycles. Water that refreezes on the coil or base pan can jam the fan.
• Roof runoff. A unit under an eave takes drips that turn to ice.
• Fall leaves and spring cottonwood. Debris packs the coil and chokes airflow in both seasons.
• Aging pairings. An older heat pump paired with electric strip heat shows its faults on the first cold night.

How we diagnose a heat pump that is not heating

We start at the thermostat and move outward, because a setting is the cheapest fault to find.

• Settings. The thermostat should be in heat mode, not Auto, with no stray emergency-heat call.
• Airflow. Filter, blower and indoor coil are checked first, since weak airflow mimics a refrigerant problem.
• Outdoor unit. Fan, capacitor, contactor and coil condition are tested with a meter, not replaced on a hunch.
• Defrost. The defrost board and its temperature sensors are tested for the right sequence.
• Reversing valve and refrigerant. Pressures and temperatures show whether the valve is shifting and whether the charge is correct.
• Backup heat. Strips and their relays are checked so you have heat while the main repair is quoted.

Then we explain what failed. On an air conditioner, Margaret S. had been told a capacitor was replaced. The technician found that the fan blades were not moving and the motor was going out. The same habit applies to a heat pump.

Which repairs fix which heat pump faults?

Most repairs fall into five groups, and the right choice depends on age and condition.

If a compressor or coil has failed, put that quote next to heat pump installation. Repair makes sense when it is the cheaper road to years of use, and we will say when it is not.

What happens on the repair visit, step by step?

The visit follows a fixed order so you are never surprised by a bill.

1. You describe the symptom and what you have already tried.
2. We inspect in the order above and keep notes on readings.
3. We explain the finding in plain language and give options.
4. You get a clear, upfront quote before any part is ordered or installed.
5. If you approve, the repair is made and the unit is run through heat and defrost.
6. We check what else is working: backup heat, drain, thermostat call.

Many electrical repairs finish on the first visit, though parts availability decides. After a fix, expect heat to recover over a cycle or two, not instantly. One Google reviewer, Gaquan C., wrote that someone came out in 10-degree weather.

What does a heat pump repair visit cover?

• Reversing valve, defrost board and sensor tests in heat and cool modes
• Outdoor coil and fan checks for ice, debris and airflow
• Refrigerant pressures, with a leak check if the charge is low
• Backup heat strips, sequencers and the air handler blower
• Thermostat wiring, including the auxiliary heat call

Which permit and license rules apply to a heat pump repair?

Missouri has no statewide HVAC license, so the office that matters depends on your address. In St. Louis County, mechanical permits and licensing run through the Department of Transportation and Public Works, and Bridgeton's city page sends all mechanical permits there. Hazelwood runs its own online permit platform under the 2021 International Mechanical Code, and Maryland Heights allows a like-for-like condenser replacement without plans. In the City of St. Louis, Ordinance 70800 covers replacement units and a $25 application fee applies. Swapping a capacitor differs from replacing a unit, so ask which your job is and who files.

What does heat pump repair cost in St. Louis?

Cost follows the part, the labor time and whether refrigerant is involved. Angi reports St. Louis HVAC labor at $75 to $150 per hour in 2026, which is a market figure, not our quote. For perspective on repair versus replacement, Homeyou puts a St. Louis heat pump installation at $5,300 to $6,971 across 332 projects (2025).

Four factors move a heat pump quote most:

• The failed part, from a sensor to a reversing valve or compressor
• Whether a refrigerant leak search is needed
• Access to the outdoor unit and the air handler
• The unit's age and refrigerant type, since servicing existing R-410A stays legal but older R-22 supply is limited

Ask the quote to separate parts, labor and any leak search. On a unit near 15 years, the typical life a Department of Energy-hosted guide gives, set a compressor or coil quote beside the installation range above.

Why Kenan Corporation when a heat pump stops heating

The proof is on Google, where Kenan Corporation holds 4.6★ from 29 reviews as of October 2026.

• Tested parts. On a central air system, Margaret S. found the part reported as replaced was not in the unit, and the real fault was a failing motor.
• Open 24 hours. A stalled heat pump on a freezing night does not wait for a weekday, and the phone is answered around the clock.
• Honest scope. Candice F. wrote that Kenan is "great at explaining things and giving you options."
• A founder's rule. Kenan Bruce Martz began the company in 2010 to replace hard-sell pitches with fair advice.

Missouri has no statewide HVAC license, so ask any contractor for the license number issued by the City of St. Louis or St. Louis County.

Where do we repair heat pumps?

Minutes are from our base near Spanish Lake in normal traffic.

• Spanish Lake, about 5 minutes: many apartment units run heat pumps, so we start at the air handler closet and condenser pad.
• Ferguson, about 20 minutes: century houses gained ducts later through closets and chases, so weak heat may be airflow before refrigerant.
• Jennings, about 20 minutes: 22 percent of occupied homes heat electrically, and newer homes with heat pumps sit among 1950s furnaces.
• Hazelwood, about 25 minutes: rentals and light-industrial buildings put condensers on side yards and flat roofs.
• Bridgeton, about 30 minutes: apartment building continued through the 1970s and 1980s, so electric heat and heat pumps are common.
• St. Charles, about 35 minutes: the city licenses HVAC contractors itself and the county issues a separate mechanical license.
• Maryland Heights, about 35 minutes: about 36 percent of units sit in structures of five or more.
• Clayton, about 35 minutes: 36 percent of occupied homes heat electrically and 65 percent of units are in multi-unit buildings.
• Mehlville, about 55 minutes: 37 percent of occupied homes heat with electricity, and the county, not a city, handles permits.

How do you keep a heat pump from freezing up again?

Prevention is airflow, drainage and timing. Change or wash filters about every 90 days, as the Center for Energy and Environment guide advises for ducted systems. Keep leaves, snow and ice-melt runoff away from the outdoor unit, and make sure meltwater drains off the pad. Use heat mode in winter and cool mode in summer instead of Auto, and avoid abrupt thermostat swings. Have a technician service the system once a year, before the first freeze.