Estimated Read Time: 9 minutes
When a heat pump not heating turns your morning into a shiver fest, stay calm. Most issues have simple checks you can try before calling for help. This guide covers the most common reasons a heat pump will not heat, quick fixes you can do safely, and when to call Sierra for 24/7 service. If you need fast help tonight, we have live answering and same-day options.
How A Heat Pump Heats Your Home
A heat pump moves heat rather than creating it. In heating mode, it absorbs heat from outside air and transfers it indoors using refrigerant. When something interrupts that transfer, you feel cool or lukewarm air.
Key parts to know in plain English:
- Outdoor unit: pulls heat from outside air.
- Indoor air handler: pushes warmed air through your ducts.
- Refrigerant circuit: the pipeline that carries heat.
- Defrost controls and sensors: keep the outdoor unit from icing up.
- Thermostat and settings: tell the system what to do.
Knowing these basics helps you spot small issues before they become big bills.
Quick Checks Before You Call
Try these fast, safe steps first. Many no-heat calls in Las Vegas and Henderson are solved here.
- Thermostat settings
- Set to Heat and Auto. Avoid On if the air feels cool.
- Bump the setpoint up 3 to 4 degrees. Wait 10 minutes.
- Power and breakers
- Check the indoor air handler breaker and the outdoor unit disconnect.
- If a breaker is tripped, reset once. If it trips again, call a pro.
- Air filter and airflow
- A clogged filter chokes heat. Replace if dirty or older than 60 days.
- Open at least 80 percent of supply registers in each room.
- Outdoor unit status
- Clear leaves or debris within 2 feet. Gently hose off dirt on the coil fins.
- If the fan is not spinning or you hear loud scraping, turn it off and call.
- Defrost cycle patience
- In cold, dry air the unit may pause and blow cooler air during defrost. This can last 5 to 10 minutes.
If heat returns after these steps, great. If not, keep reading for the most common causes.
Thermostat Or Settings Issues
Why it happens: Wrong mode, schedules, or smart thermostat logic can hold back heat.
What to try now:
- Confirm Heat mode. Some thermostats have Heat, Cool, and Emergency Heat.
- Disable energy-saving schedules for a day to test.
- Replace batteries if your thermostat uses them.
- For smart thermostats, check Wi-Fi and app settings, then restart.
When to call: If your screen is blank, wiring looks loose, or the system short cycles, you need a licensed tech. Sierra’s fully stocked vans carry common thermostat replacements so most fixes are done in one visit.
Dirty Filter, Blocked Vents, Or Duct Issues
Why it happens: Your heat pump relies on steady airflow. A dirty filter or closed vents can cause lukewarm air or safety shutdowns.
What to try now:
- Replace the filter with the correct size and MERV rating your system allows.
- Vacuum floor and wall registers. Remove rugs and furniture blocking airflow.
- Check the return grille for pet hair or dust mats.
When to call: Persistent hot and cold spots may indicate leaky or collapsed ducts. In older Spring Valley and Paradise homes, we often find crushed flex duct in attic runs. A quick static pressure test tells the story and prevents wasted energy.
Outdoor Unit Frozen Or Iced Over
Why it happens: In heating mode, outdoor coils naturally get cold. In certain conditions, frost forms. Your system should defrost itself. If it stays iced over, you lose heat.
What to try now:
- Turn the system to Off and fan to Auto. Let ice melt naturally. Do not chip with tools.
- Gently rinse the coil with a garden hose to clear light frost.
- Clear snow or debris around the base. Keep 2 feet of clearance.
When to call: If the unit ices up again within an hour, you may have a failed defrost sensor, bad reversing valve signal, or low refrigerant. Sierra techs test sensors and board logic and can often replace parts same day when stock is available.
Reversing Valve Or Stuck In Cool Mode
Why it happens: The reversing valve switches refrigerant direction between heating and cooling. If it sticks or loses its control signal, you get cool air when you want heat.
What to try now:
- Power cycle the system at the breaker for 5 minutes, then restore power. Test Heat mode again.
- Confirm the thermostat is truly commanding Heat.
When to call: Reversing valve diagnosis needs gauges and electrical tests. In North Las Vegas and Enterprise, we see this after lightning or power surges. We can verify the coil voltage and replace the valve if needed.
Low Refrigerant Or A Refrigerant Leak
Why it happens: Low charge starves the system of heat absorption. You might hear hissing, see oily residue on lines, or notice ice on the outdoor coil.
What to try now:
- Visual check only. Do not attempt to connect gauges or add refrigerant without EPA certification.
- Note any sudden drops in performance or a new whooshing sound.
When to call: This is a licensed repair. Our EPA certified team pressure tests, locates leaks, and restores the correct charge per manufacturer specs. For members, repairs come with a 2 year labor and limited parts warranty on covered work.
Auxiliary Heat Or Emergency Heat Confusion
Why it happens: Many heat pumps use electric or gas backup heat. If the heat pump cannot keep up, auxiliary heat engages. Emergency Heat forces the backup to run by itself.
What to try now:
- Avoid using Emergency Heat for long periods. It costs more to run.
- If you see Aux Heat on mild Las Vegas days, that can signal a heat pump issue.
When to call: If your power bill spikes or Aux Heat runs constantly, we will test sensors, airflow, and charge to restore normal operation.
Noisy Operation, Short Cycling, Or System Will Not Start
Why it happens: Safety switches trip due to airflow, condensate backups, or electrical faults. Short cycling can also come from oversize equipment.
What to try now:
- Check the condensate drain pan for water near the air handler. A full pan trips the float switch.
- Verify outdoor fan and indoor blower both run. If one is out, shut the system down and call.
- Listen for clicking relays or hums without fan movement.
When to call: Same-day service is available when booked by 6 pm, and our 24/7 live team can dispatch after hours. We carry common motors, capacitors, and contactors to get you heat fast.
Maintenance That Prevents No-Heat Calls
Regular tune-ups catch small issues early and keep warranties valid. In our desert climate, dust and sun age components quickly.
What a pro heat pump tune-up checks:
- Measure refrigerant pressures and superheat or subcooling to factory targets.
- Test defrost sensors, board operation, and outdoor temperature sensor.
- Inspect contactor, capacitor, and motor amperage.
- Clean indoor and outdoor coils for better heat transfer.
- Confirm thermostat calibration and staging.
- Check duct static pressure and supply temperature split.
Sierra’s S.A.M. maintenance plan is just 16 dollars per month and includes a heating tune-up, a cooling tune-up, a 65 point plumbing inspection, and priority emergency service. Members receive one included emergency service trip, 15 percent off repairs, 30 dollars off additional trips, and same-day parts replacement when available.
When To Call A Professional Immediately
Call now if you notice any of these:
- Outdoor unit silent with a tripped breaker that will not reset.
- Burning smell, scorched wires, or smoke.
- Ice that returns within an hour of melting.
- Frequent short cycling or system shuts off after 30 to 60 seconds.
- Thermostat blank or system unresponsive.
We are here when you need us in Las Vegas, Henderson, North Las Vegas, Summerlin South, Paradise, and nearby. Our BBB A+ team has won Best of Las Vegas awards and arrives in fully stocked vans to finish most repairs in one visit.
Repair, Replace, Or Wait
If your heat pump is older than 12 to 15 years, has repeated leaks, or needs a compressor, it is wise to compare repair and replacement costs.
Your options:
- Repair now for fastest heat if the issue is small and the unit is otherwise healthy.
- Plan a replacement if repair exceeds 30 to 40 percent of a new system.
- Enroll in S.A.M. to stabilize costs and get priority support.
Your home, your decision. We will show clear pricing and pros and cons for each path so you choose what fits your budget and comfort.
Simple DIY Checklist You Can Save
- Replace or wash your filter every 60 days, monthly during heavy use.
- Keep 2 feet of clearance around the outdoor unit.
- Check your thermostat batteries every 6 months.
- Open supply registers and vacuum return grilles quarterly.
- Schedule spring cooling and fall heating tune-ups.
If your heat pump still is not heating after these steps, schedule with Sierra. We offer financing options for unexpected repairs and never charge extra for nights, weekends, or holidays on qualifying services.
Special Offers To Get Your Heat Back Fast
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Special Offer: One Emergency Service Trip included with S.A.M. membership. Join for 16 dollars per month and get priority service, two HVAC tune-ups per year, a 65 point plumbing inspection, and 15 percent off repairs. Offer valid through 2026-11-04.
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Special Offer: Save the 89 dollar value of an Emergency Service Trip when included with your active S.A.M. membership. Use code SAM-EMERGENCY before 2026-11-04.
Call (702) 710-9106 or schedule at sierracoolslv.com. Mention SAM-EMERGENCY to apply the included trip if you are a member.
What Homeowners Are Saying
"One of my air conditioning units stopped working last Sunday night and when we checked it, the fan was frozen. I was worried that no one would be able to get to us that evening to repair and get us cool again. I called Sierra and they sent out a service member within the hour! Jeremy was on time, polite, professional. and very helpful. He was knowledgeable about the repair needed and was able to get it taken care of within a short amount of time. Jeremy also told me about the service agreement so we could ensure that our units are taken care of annually. I appreciated Jeremy's knowledge and service. I would 100% recommend Jeremy and Sierra."
–Cathy D., Las Vegas
"We thought we would be lucky to get service the next day and prepared for an uncomfortable night. We reached out to Troy, and soon had a tech scheduled to come out. I was astounded to get service at 10:30pm; to top it off the tech was extremely kind and efficient…to say we were impressed was an understatement"
–Homeowner, Las Vegas
"Everyone was so helpful when I was in full panic mode for a plumbing emergency! They were calm, kind and so fast. Highly recommend!! Manny was very knowledgeable and professional."
–Ashley M., Henderson
"Rachel is AWESOME. She was thorough, precise and very efficient. We loved how she gave us options and was very honest with what we needed for our supposed maintenance turned to actual emergency changing of parts/accesories."
–Justine S., North Las Vegas
Frequently Asked Questions
Why is my heat pump blowing cold air in Heat mode?
Short defrost cycles can feel cool for a few minutes. If air stays cold, check the thermostat mode, replace a dirty filter, and verify the outdoor unit is running. If frost builds or the fan is off, call for service.
Should I use Emergency Heat when it is cold outside?
Use Emergency Heat only if the heat pump is not working. It runs the backup heat alone and costs more to operate. Call a pro to restore normal heating and reduce your power bill.
How often should I replace my heat pump filter?
Every 60 days is a good rule of thumb, monthly during heavy use or with pets. A clean filter protects your system and improves heat output.
How do I know if I have a refrigerant leak?
Common signs include hissing, oily residue on lines, icing on the outdoor coil, and longer run times. Do not add refrigerant yourself. Schedule an EPA certified technician to test and repair the leak.
When should I repair versus replace my heat pump?
Consider replacement if the unit is 12 to 15 years old, needs a compressor, or if repair costs exceed 30 to 40 percent of a new system. A pro can compare options and savings based on your home and usage.
The Bottom Line
If your heat pump not heating is turning comfort into guesswork, start with the quick checks above. For anything electrical, refrigerant related, or repeat icing, call Sierra. We serve Las Vegas, Henderson, North Las Vegas, and nearby. Our 24/7 live team, fully stocked vans, and award-winning service get heat back fast. Ready for help or want priority support with S.A.M.?
Ready To Get Warm Again?
Call Sierra Air Conditioning & Plumbing at (702) 710-9106 or schedule at sierracoolslv.com. Join S.A.M. for 16 dollars per month to receive one included Emergency Service Trip and 15 percent off repairs. Mention code SAM-EMERGENCY before 2026-11-04. Let’s get this taken care of today.
About Sierra Air Conditioning & Plumbing
For 30+ years, Sierra Air Conditioning & Plumbing has kept Las Vegas homes comfortable with Service That Soars Above the Rest. Our technicians are trained, background-checked, EPA certified, and Mom approved. We are BBB A+ accredited, a Lennox Premier Dealer, and a Best of Las Vegas award winner. We offer 24/7 live answering, fully stocked vans, and honest options with zero pressure. The only installer trusted by Costco for over 16 years.