Heat Pump Not Heating? Here’s What Portland Homeowners Should Do
Portland’s winters mix rain, ice, and the occasional arctic blast. Learn how modern heat pumps behave in cold weather, how to handle defrost cycles, and when to call our emergency technicians so you stay warm all season.
Read Time
13 minute read
Emergency Hotline
503-698-5588
Service Area
Portland Metro
Owner & Lead HVAC Technician
Table of Contents
Quick Answer
Heat pumps lose efficiency below 35°F, entering defrost cycles that are normal in Portland winters. Abnormal issues include no heat at all, frequent defrosts, or ice buildup. Check thermostat settings, filters, reset system. Call professional for persistent problems. Consider dual-fuel systems for reliable heating below 30°F.
| Symptom | Possible Cause | Solution |
|---|---|---|
| No heat at all | Low refrigerant or thermostat fault | Call professional for diagnosis |
| Long run times | Normal cold weather operation | Allow system to work, monitor |
| Frequent defrost cycles | Dirty coil or low airflow | Clean coil, replace filter |
| Ice buildup on coil | Defrost failure or airflow issue | Reset system, call service if persists |
| Auxiliary heat runs constantly | Cold temperatures below balance point | Normal, consider dual-fuel upgrade |
Cold Weather Heat Pump Basics for Portland
Heat pumps exchange heat with outdoor air. As temperatures drop, capacity and efficiency decline. Knowing these fundamentals helps you distinguish expected performance from genuine problems during Portland’s winter weather.
Design Temperature Matters
Portland’s design temperature is 24°F. Manufacturers size heat pumps so they meet most heating demand down to that point. When the Gorge sends 18°F air into the metro, auxiliary heat picks up the slack.
Cold Climate Models Perform Better
Bryant Evolution Extreme, Carrier Infinity 26, and Trane XV20i heat pumps keep higher output at low temperatures thanks to inverter-driven compressors and advanced defrost control. Ask about these options when upgrading older systems.
Temperature vs Output: What to Expect
Use this chart to understand how your heat pump performs at common winter temperatures. Knowing the expected output keeps you confident during frosty mornings and helps you explain concerns when calling for service.
40°F (Typical November Day)
Efficiency: 3.2 – 3.4 COP
Heating Output: Delivers 100% heating capacity with minimal auxiliary heat. Expect steady supply air temperatures between 95–105°F.
Portland Insight: Great opportunity to run continuous fan mode for indoor air quality during rainy spells.
32°F (Freezing Rain Event)
Efficiency: 2.5 – 2.8 COP
Heating Output: Slight drop in capacity; defrost cycles occur every 45–90 minutes. Supply air temps hover around 90–95°F.
Portland Insight: Expect auxiliary heat strips to supplement during long defrost cycles.
24°F (Design Temperature for Portland)
Efficiency: 2.1 – 2.4 COP
Heating Output: Most cold-climate heat pumps retain 75–85% heating capacity. Auxiliary heat engages more frequently.
Portland Insight: Monitor energy usage; dual-fuel systems may switch to gas furnace based on setpoint.
18°F (Arctic Blast)
Efficiency: 1.7 – 2.0 COP
Heating Output: Capacity drops sharply; without auxiliary or gas backup, indoor temps may drift 2–3°F below setpoint.
Portland Insight: Ice accumulation on outdoor coil requires active defrost and proper drainage to avoid shutdowns.
Curious how your system stacks up? Schedule a performance evaluation with our heat pump maintenance team to review runtime data and energy usage from last winter.
Defrost Cycles Explained (It’s Normal!)
Portland’s humid air causes frost to form on outdoor coils whenever temperatures dip below 40°F. Defrost cycles protect the system. Understanding the sounds and visuals prevents unnecessary panic.
What Happens: The heat pump temporarily reverses into cooling mode, sending warm refrigerant through the outdoor coil to melt frost. The outdoor fan stops, the compressor changes pitch, and steam rises.
How Long It Lasts: 5–10 minutes per cycle. Cold-climate systems adjust frequency based on sensor readings. Frequent cycles during freezing rain are normal.
When to Worry: If ice remains after defrost, or you hear grinding or screeching sounds, shut the system off and switch to Emergency Heat. Schedule service before ice damages the fan blades or coil.
Seven Troubleshooting Steps You Can Try
If your home feels cooler than expected, walk through these safe checks before calling for service. Many issues stem from airflow or thermostat settings you can address quickly.
Confirm Thermostat Mode & Setpoint
Set the thermostat to HEAT with a temperature at least 3°F above room temperature. Ensure “Aux Heat Lockout” is not set too low on smart thermostats during Portland cold snaps.
Check Outdoor Unit for Ice Coverage
Light frost is normal. If the outdoor coil is encased in thick ice for over 60 minutes, shut the system off, switch to Emergency Heat, and call our team for service.
Inspect Air Filters and Return Vents
Restricted airflow causes low supply temperatures. Replace filters monthly in winter and keep return vents unobstructed, especially in tight Portland homes with built-in cabinetry.
Verify Breakers for Air Handler & Heat Strips
Two breakers typically feed the indoor unit—one for the blower, another for heat strips. Reset tripped breakers once. If they trip again, leave them off and request professional diagnostics.
Listen for Defrost Cycle Indicators
During defrost, you may hear a swooshing sound and see steam. The outdoor fan stops while refrigerant reverses to melt ice. This is normal behavior lasting 5–10 minutes.
Confirm Outdoor Unit Clearance
Clear snow, leaves, or holiday decorations within 24 inches of the cabinet. Portland’s wet leaves can block airflow overnight; keep shrubs trimmed.
Check Condensate Drain & Float Switch
Frozen or clogged drains trigger safety switches that shut down heating. Ensure condensate pumps in basements or crawlspaces are operating and discharge lines are insulated.
Normal vs Abnormal Winter Behavior Checklist
Heat pumps sound and behave differently during winter. Use this checklist to determine whether you can wait it out or if your system needs immediate attention from our Portland technicians.
Normal Operation
- Outdoor unit steams during defrost; fan stops temporarily.
- Thermostat displays “Aux Heat” or “Stage 2” for short intervals.
- Indoor temperature drops 1–2°F below setpoint during 20°F cold snaps.
Needs Attention Soon
- Continuous ice buildup that does not melt after a defrost cycle.
- Breaker trips more than once in a day.
- Unusual grinding or metallic sounds from outdoor fan motor.
Emergency Service Required
- Burning smell, smoke, or scorched wiring at the air handler.
- No heat output with Emergency Heat activated.
- Outdoor fan not spinning while compressor runs continuously.
Auxiliary & Emergency Heat Guidance
Auxiliary and emergency heat keep your home warm when the heat pump can’t keep up. Used correctly, they protect your comfort without wasting energy.
Auxiliary Heat Strips
Electric heat strips add 5–15 kW of backup heating. They automatically engage when supply air temperature drops or the thermostat senses the home falling behind by 2–3°F.
Emergency Heat Mode
Use Emergency Heat if the outdoor unit is iced over, you hear abnormal noises, or the compressor fails. This bypasses the outdoor unit and relies solely on electric resistance heat or gas backup.
Lockout Settings
Smart thermostats allow heat pump lockout temperatures. We recommend setting lockout near 25°F for standard heat pumps and 15°F for cold-climate models installed around Portland.
Power Consumption
Expect electric usage to spike when auxiliary heat runs. Monitor your PGE account or smart thermostat app to track runtime and avoid surprises on winter bills.
Need help configuring smart thermostat lockouts or auxiliary settings? Book a visit with our troubleshooting specialists to customize your system for Portland’s rate schedules.
When Dual-Fuel Systems Make Sense in Portland
Dual-fuel systems combine an electric heat pump with a high-efficiency gas furnace. They are popular across the Portland metro where winter ice storms and power outages demand resiliency.
Automatic Fuel Switching
Dual-fuel systems run the heat pump above a chosen temperature (often 32°F) and seamlessly switch to gas furnace heat during deep freezes. This preserves comfort without excessive electric usage.
Resilience During Ice Storms
If freezing rain disables the outdoor unit, the gas furnace side keeps your Portland home warm. Perfect for neighborhoods prone to power blips and heavy icing like West Linn or Troutdale.
Optimized Energy Costs
Hybrid controls compare PGE electricity rates with NW Natural gas prices every cycle, choosing the cheapest fuel source while maintaining setpoint.
Improved Lifespan
Reducing strain on the heat pump during extreme cold extends compressor life, lowering the chance of mid-winter breakdowns.
Interested in hybrid comfort? Explore options with our furnace replacement team or heat pump designers. We model utility costs and rebates for your specific home.
When to Call for Professional Service
Some symptoms require licensed technicians immediately. Use these triggers to decide when to contact Efficiency Heating & Cooling for emergency service.
Outdoor unit coated in solid ice for more than one hour.
Turn system off, switch to Emergency Heat, and call our no-heat emergency team immediately for same-day service. Prolonged icing can damage the compressor.
Breaker trips repeatedly or you smell burning insulation.
Leave the breaker off and contact our 24/7 emergency technicians for electrical diagnostics. Do not reset the breaker—this indicates a serious electrical fault.
Indoor temperature drops more than 5°F below setpoint despite auxiliary heat running.
Schedule a priority visit with our Portland heat pump repair specialists to test refrigerant charge and defrost sensors. Low refrigerant or faulty sensors prevent efficient heating.
Error codes on smart thermostat or inverter board.
Record the code, reboot once, and call for service. We carry manufacturer-specific diagnostic tools for Bryant, Carrier, Trane, and Mitsubishi systems.
Portland Cold Snap Preparedness Plan
Preparation keeps your household safe and comfortable when the forecast calls for freezing rain or snow. Follow this proactive plan before the next cold spell hits.
Pre-Winter Maintenance
Schedule a fall tune-up through our Comfort Club. We test defrost sensors, heat strips, refrigerant charge, and surge protectors before cold weather arrives.
Insulate & Cover Exposed Lines
Ensure refrigerant lines are insulated and protected from Portland rain and ice. Replace cracked insulation sleeves to prevent freeze-ups.
Stock Emergency Supplies
Keep space heaters, blankets, and battery backup for Wi-Fi thermostats on hand. This supports health and safety during outages or while waiting for service.
Monitor Energy Usage
Use PGE’s online dashboard or your smart thermostat app to monitor kilowatt usage. Sudden spikes may indicate frozen coils or failed heat strips.
Plan for Dual-Fuel Upgrade
If your all-electric system struggles every winter, explore dual-fuel or cold-climate upgrades with our heat pump replacement team. Modern cold-climate heat pumps work efficiently down to -15°F, and dual-fuel systems automatically switch to gas when temperatures drop.
Frequently Asked Questions About Cold Weather Heat Pump Performance
These answers cover the most common concerns Portland homeowners share during cold snaps. If your question isn’t listed, our team is ready to help.