Livermore, CO Heat Pump Not Heating? 7 Likely HVAC Causes

Estimated Read Time: 9 minutes

Is your heat pump not heating like it should? When a heat pump is not heating, comfort drops fast, especially during a Fort Collins cold snap. The good news is most issues trace back to a handful of causes you can spot early. In this guide, you will learn simple checks, smart fixes, and when to call our NATE-certified pros. Bonus: see current rebates that can offset repair or replacement costs.

Quick symptoms to note

Before you dive into troubleshooting, confirm the exact symptom. Different symptoms point to different fixes.

1. Feels like room temperature air from vents
   • Often a thermostat setting issue or defrost cycle timing.
2. Heat briefly works, then drops off
   • Could be icing, airflow restriction, or a control fault.
3. Long run times with poor heat
   • Common with dirty filters, low refrigerant, or duct leaks.
4. Outdoor unit silent or iced over
   • May indicate a failed component or defrost fault.
5. High energy bills with low comfort
   • Often a sign of airflow or refrigerant problems, or improper sizing.

Tip: Heat pumps deliver warm, not hot, supply air. That is normal. If supply air never rises above room temperature after several minutes, take the steps below.

Cause 1: Incorrect thermostat setting or mode

The thermostat is the simplest place to start and the easiest to overlook. A heat pump thermostat must control both heating and cooling along with auxiliary heat.

What to check

• Confirm the system is set to Heat, not Cool or Auto.
• Set temperature 3 to 5 degrees above current room temp.
• Look for indicators like “Aux Heat” or “Emergency Heat.” Aux is normal in very cold weather. Emergency should be used only if the heat pump fails.
• Verify the fan setting is Auto, not On. Fan On can blow room temperature air continuously.

Fixes that help

• Replace thermostat batteries if the display is dim or erratic.
• If a new thermostat was installed, confirm it is heat pump compatible and configured for your system type, including reversing valve setting.
• If the system still will not respond, a professional should test low-voltage control wiring and staging logic.

Why it matters: Wrong settings force inefficient cycles or no heat at all. With correct configuration, most homes feel warmer within minutes.

Cause 2: Dirty filter or indoor coil restricting airflow

Restricted airflow is the enemy of heat pump performance. A clogged filter or dust-matted indoor coil limits heat transfer and makes the system run longer with little comfort gain.

What to check

• Inspect the return filter. If you cannot see light through it, it is time to change it.
• Open supply registers in bedrooms and living spaces. At least 80 percent of registers should be open.
• Listen for whistling at the return grille. That can signal a starved airflow path.

Fixes that help

• Replace 1-inch filters every 30 to 60 days in peak season. Media filters may last longer. Follow manufacturer guidance.
• Do not oversize the filter MERV rating. Extremely high-MERV filters can choke airflow in systems not designed for them.
• Schedule a professional coil cleaning if dust or microbial growth is visible on the indoor coil or blower wheel.

Why it matters: Clean airflow restores capacity and protects compressors and motors from overheating.

Cause 3: Outdoor unit blocked or iced over

Your outdoor unit must breathe. Snow drift, leaves, cottonwood fluff, or fencing placed too close will starve the coil. In freezing weather, frost is normal, but a full ice shell is not.

What to check

• Clear a 2- to 3-foot area around the unit on all sides and above.
• Look for a solid ice buildup on the coil or base pan.
• Listen for a periodic defrost cycle. The outdoor fan should stop and steam may rise. That is normal.

Fixes that help

• Gently remove debris with a soft brush. Do not bend coil fins.
• If iced, turn the system off at the thermostat and use the Defrost mode if available. Never chip ice with tools.
• A pro should test sensors, defrost control board, outdoor fan, and cold-weather charge. In Northern Colorado, proper defrost is essential during temperature swings near Horsetooth Reservoir and along the Poudre.

Why it matters: A blocked or iced coil cannot absorb heat from outside air. Defrost faults or airflow blockages can cut capacity by more than half.

Cause 4: Low refrigerant or a refrigerant leak

Heat pumps depend on precise refrigerant charge. Low charge reduces heat output, creates long run times, and can damage the compressor.

What to check

• Weak heat with no obvious airflow or thermostat issues.
• Hissing or oily residue at fittings is a red flag for leaks.
• Frequent icing on the outdoor unit or indoor coil.

Fixes that help

• Only an EPA-certified technician should measure superheat, subcooling, and weigh in the correct charge.
• Leak detection may include dye, nitrogen pressure testing, and electronic sniffers.
• After repairs, the system must be evacuated and recharged to the exact manufacturer specification.

Why it matters: Topping off without repairing the leak is a costly short-term fix. Proper repair restores capacity and protects your equipment.

Cause 5: Reversing valve or defrost control faults

The reversing valve directs refrigerant flow for heating or cooling. If it sticks, you will get cool or lukewarm air in Heat mode. The defrost system controls when and how the outdoor unit clears ice.

What to check

• Heat mode selected, but supply air never warms.
• Outdoor unit fails to enter defrost during freezing weather, or enters too often.
• Clicking or humming at the outdoor unit without proper temperature change.

Fixes that help

• A technician will test solenoid voltage, valve operation, and control board logic.
• Defrost sensors must be within specification. Replacement may be required if they drift.
• Firmware or board updates may be available on newer models.

Why it matters: Control issues often mimic other problems. Accurate diagnosis avoids wasting money on parts you do not need.

Cause 6: Duct leaks or zoning problems

Leaky ducts lose heat into attics, crawlspaces, or garages. Zoning problems leave parts of the home starved for airflow. Both slash comfort and drive up bills.

What to check

• Rooms that never reach setpoint, especially upstairs.
• Noticeable drafts or rattling at duct joints.
• Multiple thermostats that fight each other or zones that never open.

Fixes that help

• Have ducts pressure-tested. Sealing with mastic and proper insulation can cut losses significantly.
• Balance dampers to ensure each room gets the right airflow.
• For homes with persistent hot and cold spots, consider ductless mini-splits or a properly designed zoning system.

Local note: Older homes around Old Town often have add-on ducts that were not sealed well. A quick audit pays off in comfort.

Cause 7: Aging or improperly sized equipment

Even a perfectly maintained system has a useful life. If the system is undersized or oversized, comfort suffers. Oversized units short cycle. Undersized units run long with poor heat on the coldest days.

What to check

• Age of the heat pump. Many systems last 12 to 15 years.
• Frequent repairs, rising energy costs, or noise.
• Uneven heating during wind chills and overnight lows common in NoCo winters.

Fixes that help

• Request a load calculation, not a like-for-like swap. Proper sizing and duct review are essential.
• Consider cold-climate heat pumps that maintain capacity at low outdoor temperatures.
• Hybrid solutions pair a heat pump with a furnace for peak cold. This offers comfort and savings in our climate.

Why it matters: Right sizing and modern technology can improve comfort while unlocking serious rebate opportunities.

Prevention and maintenance plan

Routine care is the easiest way to keep heat steady and avoid emergencies.

• Replace or clean filters on a schedule.
• Keep vegetation and snow away from the outdoor unit.
• Enroll in professional maintenance. Heat pumps need service twice per year because they heat and cool and run more often than single-season systems.
• Ask for a written performance report with temperature splits, static pressure, and refrigerant measurements.

Two important facts for homeowners

1. Heat pump maintenance is recommended twice each year to protect efficiency and reduce wear.
2. We back installations with a 1-year test drive and a 100 percent satisfaction guarantee, so upgrades carry less risk.

Special offers and rebates for Northern Colorado

• Upgrade to a heat pump water heater and claim a $2,250 rebate when you choose a qualified contractor. Offer expires 7/31/25.
• Air-source heat pump rebates available, typically $500 to $2,000 on qualifying systems.
• Ductless mini-split rebates available, typically $500 to $3,000.
• Save up to $12,000 in combined rebates, incentives, and tax credits on qualifying heating and cooling systems.

Call (970) 235-2177 or visit https://fortcollinsheating.com/ to confirm eligibility and schedule a free rebate review. Availability varies by utility and equipment selection.

What Homeowners Are Saying

"Shawn worked on our zoned heat pump system which was not keeping the upstairs cool. Fixed it perfectly and made the other zones work better as well. We now get more and better air flow throughout the house."
–Fort Collins Homeowner

"Cody was professional, efficient and great to work with on the installation of our new heat pump system. Its such an improvement over our old gas furnace and window AC unit."
–Loveland Homeowner

"Brent was our HVAC tech. He was polite, clean, technically very detailed and thorough! He took the time to inspect and service our heat pump/propane system fully."
–Greeley Homeowner

"We had a mini split system installed and the entire experience could not have gone more smoothly. They were very professional and explained everything they did."
–Windsor Homeowner

Frequently Asked Questions

Why does my heat pump blow cool air in Heat mode?

Heat pumps deliver warm, not hot, air. If supply air stays near room temperature, check thermostat mode, filter, and outdoor icing. If it persists, call for service.

How cold is too cold for a heat pump in Northern Colorado?

Modern cold-climate systems heat efficiently in very low temps. Older models may rely on auxiliary heat during deep freezes. Proper sizing is key.

Should I use Emergency Heat when it is very cold?

Use Emergency Heat only if the heat pump is not working. It bypasses the compressor and uses backup heat, which costs more to run.

How often should a heat pump be serviced?

Twice per year. Heat pumps work in both seasons, so biannual maintenance protects efficiency and reduces repairs.

Is repairing an older heat pump worth it?

If your system is 12 to 15 years old with repeated failures, a replacement with rebates and tax credits can be more cost effective than major repairs.

Wrap up

If your heat pump is not heating, start with thermostat settings, airflow, outdoor icing, and controls. Many fixes are simple, and the rest are faster with a pro. For trusted service in Fort Collins, Loveland, Windsor, and nearby, we can diagnose and restore comfort today. Call (970) 235-2177 or schedule at https://fortcollinsheating.com/.

Ready to get comfortable again?

• Call now: (970) 235-2177
• Schedule online: https://fortcollinsheating.com/
• Ask about current rebates, including up to $2,250 on heat pump water heaters through 7/31/25

We are A+ BBB rated for over 20 years, available 24/7, and every installation comes with a 1-year test drive and a 100 percent satisfaction guarantee.

Next step

Book a same-day diagnosis or a biannual maintenance visit. Our NATE-certified team serves Fort Collins, Greeley, Loveland, Windsor, and the surrounding communities. Call (970) 235-2177 or visit https://fortcollinsheating.com/ to schedule. Ask about rebates up to $12,000 on qualifying systems.

About Fort Collins Heating & Air Conditioning and Plumbing

Family-owned for 4 generations and serving Northern Colorado for over 85 years. Our NATE-certified technicians, in-house sheet metal fabrication, and 100% satisfaction guarantee give homeowners total confidence. We are a Bryant Factory Authorized Dealer and a 2019 Medal of Excellence winner. Enjoy our 1-year installation test drive, 24/7 service, and help securing rebates and tax credits.