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December 8, 2025

Englewood, CO Heat Pump Not Cooling? 5 Key HVAC Causes

Estimated Read Time: 10 minutes

Heat pump not cooling your home? You are not alone, especially during Denver’s dry, high-altitude summers. The good news is most cooling issues trace back to a few fixable causes. In this guide, you will learn the top five reasons a heat pump stops cooling, quick DIY checks, and when to call Fix-it 24/7 for fast, professional help. Bonus: simple tips to prevent repeat breakdowns and save on energy.

Quick DIY Checks Before You Call

Run through this 60-second checklist. If any step fails, move to the matching section below.

  1. Thermostat set to COOL, fan set to AUTO, and temperature set at least 3 degrees below room temp.
  2. Outdoor unit running and free of debris, cottonwood fluff, and grass clippings.
  3. Replace or clean the air filter if it looks gray, dusty, or more than 60 days old.
  4. Supply vents open, return grills not blocked by furniture or rugs.
  5. Check the breaker for the air handler and outdoor unit. Reset once if tripped.

Local tip: late spring in the Front Range brings cottonwood fluff that blankets outdoor coils. A light brush-off can restore airflow and cooling.


Reason 1: Thermostat or Mode Settings Are Off

If the thermostat is on HEAT or set to EM HEAT, your heat pump will not cool. A mis-scheduled program can also override your setpoint.

What to do:

  1. Set to COOL and AUTO fan. Avoid ON fan during troubleshooting.
  2. Lower your setpoint at least 3 degrees below indoor temperature.
  3. Review schedules and hold settings. Disable vacation or eco modes if recently used.
  4. If you have a smart thermostat, confirm it is configured for a heat pump.

When to call: If the thermostat fails to control the system or reverts settings, a pro can test wiring, sensors, and compatibility. Our technicians are trained on major controls and can replace or reprogram without voiding warranties.

Reason 2: Outdoor Unit Is Dirty or Airflow Is Blocked

Your heat pump cannot reject indoor heat if the outdoor coil is covered in dirt, cottonwood fluff, leaves, or hail-bent fins. At 5,280 feet, dry air and wind push debris into fins quickly.

Signs:

  • Outdoor fan runs, but the air from the top feels only mildly warm.
  • Ice on the refrigerant lines or coil during cooling.
  • System short cycles and struggles to reach setpoint.

DIY steps:

  1. Shut off power at the disconnect.
  2. Gently remove debris around the unit. Keep 2–3 feet of clear space.
  3. Rinse the coil from inside out with a garden hose on low pressure. Do not use a pressure washer.
  4. Carefully straighten minor fin bends with a fin comb.

When to call: If cooling does not improve, a deep clean may be required. Our team disassembles, cleans, and inspects components other companies never touch, then tests pressures and temperatures for verified performance.

Reason 3: Clogged Filters or Frozen/Dirty Indoor Coil

Restricted indoor airflow leads to poor cooling and possible freeze-ups. Wildfire smoke and dust can clog filters faster along the Front Range.

What to check:

  • Filter: Replace 1-inch filters every 30–60 days during cooling season.
  • Vents: Open at least 80% of supply registers. Keep returns fully clear.
  • Coil: Ice on the air handler or suction line means airflow issues or low refrigerant.

DIY steps:

  1. Replace the filter and run the fan on AUTO.
  2. If iced, turn the system OFF and fan ON for 2–3 hours to defrost, then try cooling again.

When to call: Persistent icing or weak airflow suggests a dirty evaporator coil, blower issues, or duct problems. We measure static pressure, inspect the coil, and verify blower speed to restore proper cfm and comfort.

Reason 4: Low Refrigerant or a Refrigerant Leak

A heat pump that runs but does not cool may be low on refrigerant. Telltale signs are warm air at vents, long run times, and little condensate at the drain.

Facts to know:

  • Heat pumps move heat using refrigerant. If levels are low, there is a leak.
  • Recharging without leak repair is a temporary fix and can damage the compressor.

Pro steps we perform:

  1. Electronic leak search and UV dye where appropriate.
  2. Repair or replace leaking components.
  3. Evacuate, weigh in refrigerant to manufacturer spec, and verify superheat/subcooling.

Why it matters: Many manufacturers require professional installation and service to maintain warranty coverage. Our EPA and NATE-certified technicians follow those guidelines to protect your investment.

Reason 5: Reversing Valve, Defrost, or Control Faults

If your heat pump cools intermittently or blows neutral air, a control fault is likely.

Common culprits:

  • Reversing valve stuck between modes.
  • Failed defrost board confusing cooling mode during summer hail or rain.
  • Faulty outdoor fan capacitor or contactor.
  • Sensor or control board failure.

What you can do:

  • Power cycle the system at the breaker for 5 minutes, then retry cooling.
  • Note error codes on your thermostat or outdoor board window if visible.

When to call: Control and valve repairs require specialized tools and brazing skills. We stock common parts for brands like Carrier, Goodman, Mitsubishi, Rheem, Trane, and American Standard to get you cooling fast.

Bonus: Ductless Mini-Split Not Cooling

Mini-splits are efficient and perfect for zoning, but they still need airflow and clean coils.

Quick checks:

  1. Clean the washable filter in each indoor head monthly during heavy use.
  2. Confirm the outdoor unit is clear and fans are spinning freely.
  3. Make sure vanes are set to cool mode and aimed slightly upward for better mixing.

If issues persist, we inspect for communication errors, drain clogs, and low refrigerant. We service multi-zone and single-zone systems and can add zones for hot upstairs rooms.

Repair or Replace: How to Decide

A quality repair often restores like-new performance. Replacement may be wiser if your system is old, inefficient, or has repeat compressor or leak failures.

Helpful benchmarks:

  • Air-source heat pumps can provide efficient heat down to around 20°F. Modern models list SEER and HSPF ratings, with some reaching SEER 20 and HSPF 13.
  • Typical installed costs vary widely by home and equipment. Air-source installations may range from $3,500 to $7,500. Ground-source systems can be between $15,000 and $30,000.

Choose replacement when:

  1. The system is over 12–15 years and needs a major component.
  2. Your energy bills have climbed despite maintenance.
  3. You want improved comfort, zoning, and rebates that require higher efficiency.

We install air-source, ductless mini-split, and geothermal systems and can replace an existing unit with another brand that better fits your home. Estimates on new systems are always free.

What a Professional Diagnostic Includes

Our proven process gives you answers on the first visit and protects your warranty.

  1. Full consultation to understand symptoms, home layout, and comfort goals.
  2. System test: temperature split, static pressure, electrical, and refrigerant analysis.
  3. Root-cause report with photos and options at flat-rate prices.
  4. Manufacturer-spec repairs and commissioning, including sensor calibration.
  5. Customer walkthrough, maintenance tips, and clean work area.

We also offer 24/7 service with a rapid response commitment. When cooling fails on a hot afternoon, you can expect expert help with a 4-hour response window on many calls.

Preventive Maintenance That Actually Works

Front Range conditions are tough on outdoor coils and filters. A set-it-and-forget-it plan prevents most no-cool calls.

Do this each season:

  1. Replace filters proactively, especially during smoke events.
  2. Hose off the outdoor coil after cottonwood season.
  3. Keep plants trimmed 2–3 feet from the unit.
  4. Schedule pre-summer maintenance for deep cleaning, electrical testing, and coil inspection.

Membership options:

  • Hero Membership: Lifetime for qualifying military, firefighters, EMS, and law enforcement. Includes bi-annual heating and cooling maintenance, annual plumbing maintenance, free estimates, and priority scheduling.
  • Green Club Membership: Low annual fee. Benefits include 25% off HVAC repairs, free furnace and AC deep cleans, water heater flushes, electric inspections, and more. Each monthly payment is credited to your account and can be used for future repairs.

These plans are designed to keep your system running at its best year-round. Members receive annual maintenance services and priority help when it matters most.

Special Offer: Free Heat Pump Installation Estimate

Planning a replacement or adding a new zone? Get a free heat pump installation estimate from Fix-it 24/7. Call 303-536-1616 or book at https://fixmyhome.com/ today. No pressure, no obligation.

Frequently Asked Questions

Why is my heat pump running but not blowing cold air?

Incorrect thermostat mode, a dirty outdoor coil, or low refrigerant are common causes. Start with thermostat settings and a clean filter. If airflow is fine but air is still warm, schedule a professional diagnostic to check refrigerant, coils, and controls.

Can a dirty filter really stop cooling?

Yes. A clogged filter restricts airflow, reduces cooling capacity, and can freeze the indoor coil. Replace 1-inch filters every 30–60 days during summer and more often during smoke or dust events.

How long should a heat pump run to cool my home?

On hot days, expect longer cycles. If your system runs constantly with little temperature drop, suspect airflow issues, a dirty coil, or low refrigerant. A 15–20 degree temperature split across the coil is a healthy target.

Should I use the fan ON setting to help cooling?

Use AUTO. Fan ON can re-evaporate moisture from the coil and reduce comfort. It may be useful for short periods after a filter change, but keep AUTO for normal cooling.

When is it smarter to replace than repair?

Consider replacement if the system is 12–15 years old with a major failure, if energy bills are rising, or if you want higher efficiency and zoning. Modern air-source units can reach SEER 20 and HSPF 13 for better comfort and savings.

The Bottom Line

If your heat pump is not cooling, start with simple checks: thermostat, filter, and a clean outdoor unit. For refrigerant leaks, control faults, or frozen coils, professional service restores comfort fast. In the Denver Metro, we understand cottonwood, hail, and high-altitude demands. Estimates on new systems are always free.

Ready to get cool again? Call Fix-it 24/7 at 303-536-1616 or schedule at https://fixmyhome.com/. Ask about your free heat pump installation estimate and our Green Club savings. We are available 24/7 with a rapid response commitment to get you comfortable today.

About Fix-it 24/7 Plumbing, Heating, Air & Electric Family owned and trusted across the Denver Metro, Fix-it 24/7 delivers expert HVAC, plumbing, electrical, and drain service. Our EPA and NATE-certified technicians follow manufacturer guidelines to protect your warranty. We hold an A+ BBB rating, thousands of 5-star reviews, and industry honors like Angie’s List Super Service Award and Home Advisor Top Rated. You get flat-rate pricing, 24/7 availability, and a 100% satisfaction guarantee. We also offer financing through GoodLeap, Wells Fargo, and GreenSky to make upgrades affordable.

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