Your Heat Pump Is Blowing Cold Air?

by | Nov 30, 2017 | HVAC Blog

How Do Heat Pumps Work?

Heat pumps are engineered to keep your home cool in the summer and warm in the winter. It removes heat from inside your home and vents it outside- to cool your home. Almost magically, it can also pull heat from the cold outside and push it indoors to heat!

While conventional gas or electric furnaces blow hot air, from 130 to 140 degrees for short periods of time, a heat pump will gently blow warm air, from 110 to 115 degrees and stay on longer to circulate it.

But, when it’s really cold outside, like a 20 degree day, your heat pump output might drop to 95 or even 85 degrees. Because this temperature is less than your body temperature, and less than the warmth you usually feel blowing, it feels like your unit is blowing cold air even though the air is actually warmer than your indoor house temperature -and warmer than where you might set the thermostat.

If the air it’s blowing is warm, why do I feel cold?

You are feeling a relative loss of heating efficiency, even though your heat pump is actually working harder to keep up with your home’s heat loss to the cold environment. When the temperature in the house drops about 2 degrees below the set thermostat temperature, supplemental heat comes from backup electric resistance heaters to assist the heat pump. When room temperature gets to within one and a half degrees of the set thermostat temperature, the back-up heat cycles off and the heat pump continues unassisted. Because of the extreme exterior cold it will keep trying to reach the set thermostat temperature, but won’t be able to quite get there.

This cold-weather specific problem is very common and causes many service calls, and although it is sometimes associated with a genuine malfunction, in extremely cold weather, even a properly working heat pump may have trouble maintaining the desired temperature. In the desert this should only happen when outdoor temperatures are at their coldest – 0 to 30 degrees.

During these unusual conditions, Oasis recommends you raise your thermostat by 2 degrees temporarily to maintain a comfortable temperature. So, for example, if you normally set your thermostat at 70 degrees in the winter and your house only ever seems to get up to 68, move your thermostat to 72. This way, your ambient temperature will feel like 70 degrees, right where you want it!

When you have a heat pump, it is very important to be sure you have energy efficient insulation, windows, window coverings and weather stripping to minimize heat gain and losses during extreme weather. Read on to see what else you can do yourself!

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What to check if you think your heat pump is not working:

  1. Check the THERMOSTAT first. Make sure it turned ON and set to HEAT- and make sure the set temperature is not lower than the actual room temperature! The furnace won’t turn on if the thermostat is set at 60 and the room temperature is 68 degrees which may be easily overlooked on an unfamiliar thermostat.
    Try setting the temperature 2 to 4 degrees above the set thermostat temperature. (FYI- If troubleshooting a heat pump in summer in cooling mode, the process is similar- just set the temperature below the set temperature.)
    Turn on the FAN. If the fan doesn’t start, check your circuit breakers and fuses and replace them if needed. If the fuse is blown or the breaker flipped, you may need to call Oasis for help to determine the cause of the overload (i.e.: a bad connection, a seized blower motor or a controller board short.)
    If your fan works, but you still have cold air, check to see if you get warm air when the thermostat is set to EMERGENCY HEAT, which is at least five degrees above room temp. If you feel warm air, then you need a technician to check the outdoor unit. If you don’t feel warm air, you may have a defective thermostat or air handler.

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What else can you do yourself?

There are a few other things to look for while troubleshooting your heat pump:

* You See The Exterior Unit Is Iced Up. This may mean the defrost timer isn’t putting the unit into defrost mode; or refrigerant charge is low; or refrigerant flow is restricted by a bad metering device.

* You See The Refrigerant coils are Dirty. Coils covered with dirt significantly diminish efficiency.

* You Notice Your Unit Is Running In Air Conditioning Mode. This may be due to a malfunction of the reversing valve which usually automatically switches from cooling to heating.

* You can’t hear the compressor running. The compressor needs professional troubleshooting.

* If you didn’t blow a fuse or trip the circuit breaker, Look For Loose, Frayed Or Worn-Out Wiring on your heat pump. The problem could also be a defective thermostat or a jammed fan relay.

* Clear Away Encroaching Plants, Trash, Leaves, Snow Drifts Or Any Other Obstructions which lay against the outdoor unit.

* A Disconnected Air Handler In The Attic or basement will pull in cold, unconditioned air.

With an Oasis Service Agreement cold weather tune-up you can rest in comfort, assured your heat pump has been cleaned, refrigerant has been checked for leaks or restrictions, system has been recharged, wiring is safe and aging parts have been repaired.

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We hope this information helps you, but please remember if you’re too hot or too cold, or you don’t feel comfortable troubleshooting or maintaining your HVAC equipment yourself, be sure to get it done by your trusted local trained professionals at Oasis.

Please keep in mind that the information found on our website is intended as a customer service courtesy. It is not inclusive of all possible situations, and Oasis does not assume any liability resulting from the informational guidelines we present here. Your HVAC system should be regularly inspected and serviced by a trained technician.

Trane. (2015). Heat Pump Troubleshooting Guide.


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