Longmont, CO Heat Pump Not Blowing Hot Air? Fixes

Estimated Read Time: 10 minutes

Heat pump not blowing hot air? Before a cold Front Range evening turns rough, use this quick guide to find the simple fix and know when to call for help. In most Denver homes, the cause is airflow, a thermostat setting, a defrost cycle, or a signal issue. Follow the steps below, and if you need a hand today, our same‑day heat pump repair team can get you comfortable fast.

Quick Checks When Your Heat Pump Is Not Blowing Hot Air

Heat pumps move heat, so the supply air often feels warm, not hot like a gas furnace. Start with these basics before you worry about major failures.

1. Wait a few minutes after setting Heat mode. Many systems need 5 to 10 minutes to ramp up.
2. Verify the thermostat is on Heat and the fan set to Auto.
3. Check that no one recently set the system to Cool.
4. Confirm the breaker and furnace switch are on.
5. Listen outside. The unit should run quietly, without harsh metal scraping or repeated clicking.

If air is room temperature after 10 to 15 minutes, move to the thermostat and airflow checks below.

Set the Thermostat for Heat, Not Emergency or Cool

A surprising number of no‑heat calls are settings.

• Heat vs Cool: Set to Heat and a temperature above current room temp.
• Fan: Use Auto. On can feel like cold because it moves air without heat.
• Emergency Heat: Only use this if the outdoor unit is down. It forces electric or gas backup and can be costly.
• Schedules: If you use schedules, try Hold or Temporary Override to test heat.
• Batteries and power: Replace thermostat batteries if the screen is dim or blank. Confirm the indoor air handler has power.

If the thermostat is correct, the next biggest culprit is airflow.

Airflow First: Filters, Vents, and Duct Issues

Restricted airflow equals lukewarm air at the vents.

• Filter: Replace a dirty filter. In Denver’s dry climate, dust builds quickly, and cottonwood season can be brutal on filters. Use a quality pleated filter sized correctly.
• Vents: Open supply registers and return grilles. Do not close off rooms. It increases static pressure and reduces comfort.
• Ductwork: Look for kinks or disconnected flex duct in attics or crawlspaces. Seal obvious gaps with foil tape, not cloth duct tape.
• Indoor coil: If you see icing on the indoor coil, turn the system off and switch the fan to On for 30 minutes to melt ice, then try again.

If airflow is clear but air still feels cool, step outside.

Outdoor Unit in Cold Weather: Defrost Cycle and Ice Buildup

On cold mornings along the Front Range, heat pumps regularly frost up. That is normal. The system runs a defrost cycle to melt ice.

• What it looks like: Steam rises, the outdoor fan may stop, and you may hear a hum. This typically lasts 5 to 15 minutes.
• Normal vs abnormal: A light glaze is fine. A solid block of ice around the cabinet or coil is not.
• Quick fixes:
• 1. Gently clear snow away from the unit. Keep 12 to 24 inches of space on all sides.
  2. Wash cottonwood fluff and leaves off the coil when weather allows.
  3. Do not chip ice with tools. You can damage the coil.

If the unit never enters defrost, or it ices up again within an hour, you may have a sensor, reversing valve, or control issue that needs a pro.

Balance Point and Aux Heat: What Warm Should Feel Like

Heat pumps can heat efficiently until outdoor temps fall near your home’s balance point. Below that temperature, auxiliary heat helps.

• Expect warm, not furnace‑hot air. Supply temperature may be 85 to 95°F.
• If air feels cool but the thermostat says Heating, auxiliary heat may not be engaging.
• Common causes: Incorrect thermostat setting, failed heat strips, or a control board problem.
• Test: Raise the setpoint by 3 to 4 degrees. You should hear a second stage or auxiliary heat engage.

If there is still no temperature rise, move to electrical and signal checks.

Electrical and Thermostat Signals: Breakers, Fuses, and Wiring

Because heat pumps tie HVAC and electrical together, a single tripped protection can stop heat.

• Breakers: Check both outdoor and indoor breakers. Reset once. If it trips again, call.
• Float switch: Full condensate pans can open a safety switch. Look for a wet area near the indoor unit.
• Low‑voltage wiring: Loose or chewed wires at the heat pump or thermostat can stop signals.
• Fuse at air handler: Many air handlers have a small low‑voltage fuse. A blown fuse means something shorted.

If breakers and fuses hold but heat still does not start, the refrigerant circuit or reversing valve may be at fault.

Refrigerant, Reversing Valve, and Compressor Clues

These components need a licensed technician. Here is how to spot symptoms.

• Low refrigerant: Long run times, little heat, possible icing. Refrigerant does not get used up, so low levels point to a leak.
• Reversing valve: Stuck in cooling can make vents feel cool year‑round. You may hear the system try to switch modes without success.
• Compressor issues: Loud starts, tripping breakers, or no pressure change during operation.
• Sensors: Outdoor ambient and coil sensors inform the defrost cycle and staging logic. Bad sensors mean bad decisions.

If you see these signs, schedule same‑day service. Our techs carry common parts to finish most repairs in one visit.

When to Repair vs Replace a Heat Pump in Denver

You deserve a clear, unbiased recommendation. Here is a simple framework we use during estimates.

• Age: Heat pumps typically last 10 to 15 years with good maintenance.
• Cost threshold: If a repair approaches 50 percent of a new system, replacement often gives better long‑term value.
• Reliability: Frequent breakdowns and hard‑to‑find parts tilt toward replacement.
• Efficiency: Modern inverter units can cut bills and reduce noise. We can install any brand and often recommend Bosch for reliability and performance.
• Ducts and electrical: We evaluate ducts and wiring so your new system is matched to your home.

We will explain options in plain language and provide a detailed quote before work starts.

Preventive Care and Our Maintenance Plan

Regular tune‑ups reduce surprise breakdowns and keep efficiency high.

What we inspect during a tune‑up:

1. Thermostat calibration and staging
2. Filters, blower wheel, and indoor coil cleanliness
3. Refrigerant pressures and temperatures
4. Outdoor coil and fan operation
5. Defrost board logic and sensors
6. Electrical connections, amperage, and safety controls
7. Duct static pressure and airflow measurements

Member benefits many Denver homeowners choose:

• Priority scheduling during cold snaps
• Repair discounts that often offset the membership cost
• Safety checks from licensed electricians and HVAC techs in one visit
• Seasonal reminders so you never miss a tune‑up

Ask about our Home Care Club for convenient recurring maintenance.

Why Choose Brothers for Same Day Heat Pump Repair in Denver

We fix the real issue, not just the loudest symptom. That means full‑system diagnostics across HVAC and electrical.

• Same‑day service across Denver, Aurora, Arvada, and the Front Range
• Licensed electricians on staff for wiring and breaker problems
• Techs stocked with common parts, tools, and gauges to finish most fixes fast
• Transparent pricing, clear estimates, and flexible financing options
• Repairs, replacements, and ductless solutions for standard, ducted, mini split, and cold‑climate units

We back our work with a satisfaction guarantee and trusted local service recognized by awards and BBB accreditation.

Special Offer: Save $50 on Heat Pump Service

Save $50 on heat pump work performed. Mention this article when you call (720) 994-7055 or schedule at brothersplumbing.com. Same‑day appointments available while open slots last.

What Homeowners Are Saying

"We've had Brothers install both a furnace (a few years ago) and a heat pump for us, and have been thoroughly pleased. Their crew are knowledgable, professional, and really great to work with, and the equipment has been top notch."
–Denver Homeowner

"Gannon inspected our heat pump and water heater for code compliance and safety. He was polite and thorough. I enjoyed talking to him."
–Westminster Homeowner

"Actually, came to give me an estimate for replacement of heat pump unit. Was scheduled for afternoon but called and we met earlier. Anthony was great, very concerned and honest."
–Aurora Homeowner

Frequently Asked Questions

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

Heat pumps deliver warm, not furnace‑hot air. If it feels cool, check the thermostat mode, filter, and outdoor unit for defrost or ice. Raise the setpoint by 3 to 4 degrees to see if auxiliary heat engages.

How long should a heat pump defrost cycle last?

Typical defrost cycles take 5 to 15 minutes. Steam and a brief outdoor fan stop are normal. If thick ice returns quickly or defrost never engages, a sensor or control issue needs service.

When should I use Emergency Heat?

Use Emergency Heat only if the outdoor unit is down or iced solid. It runs backup heat only and can increase energy costs. Return to Heat mode once the outdoor unit works.

Do heat pumps work in Denver winters?

Yes. Modern cold‑climate units heat well in Denver’s temperatures. Auxiliary heat supports comfort near or below the balance point. Proper sizing, ducts, and controls are key.

How often should I replace my heat pump filter?

Check monthly and replace every 1 to 3 months, more often during cottonwood season or renovations. A clean filter protects the compressor and improves comfort.

Final Takeaway

Most no‑heat complaints come down to settings, airflow, or a normal defrost cycle. Use the steps above to narrow the issue, then call for help if you see ice blocks, tripped breakers, or no temperature rise. For a trusted local fix of a heat pump not blowing hot air in Denver, we can be there today.

Ready for Warm Air Again?

Call (720) 994-7055 or schedule at https://www.brothersplumbing.com/. Mention this article for $50 off heat pump work performed. Need it today? Ask for same‑day service across Denver, Aurora, Thornton, Arvada, Boulder, Westminster, Centennial, Lafayette, Longmont, and Highlands Ranch.

Brothers Plumbing, Heating, and Electric is Denver’s trusted home‑service team for plumbing, HVAC, and electrical. We’re BBB accredited with an A+ rating and have earned honors like Denver Post Top Workplace and Colorado Titan 100. Our licensed techs deliver transparent pricing, financing options, and a 100% satisfaction guarantee. We handle heat pump repair, installation, and electrical troubleshooting in one visit, with same‑day service across the Front Range.