How Heat Pumps Heat Your Home in the Wintertime

Living in Houston, TX, or the surrounding area means that you’ll deal with some wild weather. Winter nighttime temperatures can drop below freezing, so you’ll need a heating system. The long, hot and humid summers mean that you also need an energy-efficient air conditioning system. With a heat pump, you get both. In moderate climates like Houston’s, heat pumps do particularly well at heating your home efficiently. Knowing how a heat pump is able to keep your Houston home warm during the winter months of the year could help you make an informed decision about which heating system to choose.

Types of Heat Pumps

There are three types of heat pumps: air-, water- and ground-source. An air-source heat pump transfers heat energy between the outdoor air and your home. A water-source heat pump uses a body of surface water, such as a pond, to transfer heat energy into and out of your home. Ground-source heat pumps, which are also called geothermal heat pumps, transfer heat between your home and a series of pipes that are buried at least 6 feet below the surface of the soil. Air-source heat pumps are the most common type of heat pump used in the Houston area.

About Air-Source Heat Pumps

An air-source heat pump uses a chemical refrigerant with the ability to absorb heat. A compressor pressurizes and pumps the refrigerant between your home and the outdoors. By transferring heat instead of generating it, the heat pump can save you a lot of money on wintertime heating costs.

How a Heat Pump Heats During the Winter

In the winter, a heat pump functions like an air conditioner in reverse. The system’s reversing valve reverses the flow of refrigerant through the system. This turns the outdoor unit into an evaporator and the indoor unit into a condenser. The outdoor unit also contains the compressor. Even when the outdoor air temperature is around 32 degrees Fahrenheit, there’s still enough heat energy to bring warmth into your home. Most heat pumps can absorb enough heat energy to warm your home even if the outdoor temperature drops down to 20 degrees Fahrenheit.

Heat Transfer Into Your Home

The heat pump’s heating function begins with the thermostat. When your home’s indoor temperature drops below the temperature setting on the thermostat, the thermostat triggers a heating cycle. The heating cycle relies on the heat pump’s reversing valve. This device triggers the refrigerant to flow from low pressure indoors to higher pressure outdoors. This movement takes place in a closed-loop system. Once the low-pressure, cold refrigerant is in the outdoor loop of the system, it absorbs heat from the outdoor air. The compressor then pressurizes the refrigerant, turning it into a hot liquid. The hot liquid flows into the indoor unit and passes through its coil. The air handler blows air across the coil. The air picks up heat from the coil. The newly warmed air enters your home’s air ducts and blows into your living spaces.

Completing the Heating Cycle

After the air handler blows air across the indoor coil, the refrigerant’s temperature drops. It condenses back into a vapor or gas. Its pressure also drops. The refrigerant flows back to the outdoor unit, completing the heating cycle.

Heat Pump Defrosting Cycle

After running many heating cycles, the outdoor unit may develop some frost or ice. This is normal. The reversing valve flips, and the heat pump will run an air conditioning cycle. This moves some heat from your home to the outdoor unit, allowing the outdoor unit’s coil to defrost. When this happens, you might notice room-temperature air blowing through your home’s vents for up to 15 minutes. There’s no cause for alarm so long as it only happens once in a while. This defrosting cycle is critical to the heat pump’s ability to absorb heat from the outdoor air during the wintertime. If you see a big chunk of ice on the outdoor unit, the heat pump’s defrost cycle might not be working properly. This situation requires a call for repairs.

Heat Pump Effectiveness During Extremely Cold Weather

Rarely, the temperature in Houston may drop below 20 degrees Fahrenheit. When this happens, the heat pump relies on an auxiliary heating system. Most heat pumps are equipped with an electric resistance heating panel. The electrical resistance wires heat up much like the wires in a toaster. This panel is located in the indoor unit near the air handler.

The air handler blows cool household air over the wires. That warm air is pumped into your home’s air ducts. When the heat pump isn’t able to absorb enough heat from cold outdoor air, the system’s safety controls turn on the emergency heating panel. Using the emergency heat consumes a great deal of electricity.

Some heat pumps have a backup gas heating system. These hybrid heat pumps offer higher heating efficiency compared to using the emergency electrical resistance panel. If you notice that your emergency heat comes on frequently or during times when it’s not below freezing, your heat pump may have a problem that requires repairs.

Maintaining Your Heat Pump in the Winter

Your heat pump needs a professional tune-up twice a year, including one before the heating season begins. Throughout the winter, check the heat pump’s air filter. It’s best to check the filter once a month. Set a reminder to check the filter on the same day of the month, such as the first Saturday.

Don’t wait more than 60 days between air filter changes. Operating a heat pump with a dirty filter causes the system to use 15% more electricity. Running the heat pump with a clogged filter could also shorten the heat pump’s lifespan. Maintain at least 3 feet of clearance around the indoor and outdoor units of the heat pump. It needs this clearance for proper airflow. Keep vegetation, including tree branches and fallen leaves, away from the outdoor unit.

Set the Thermostat During the Winter

Most heat pumps have a programmable thermostat. New models of heat pumps are also compatible with smart thermostats. In order for the heat pump to heat your home, you’ll need to program the thermostat properly. To do this, set the thermostat’s system function to “heat.” If you leave it on “auto,” there’s a chance that the heat pump could run a cooling cycle if your home gets warmer than expected. Once you have set the thermostat to “heat”, set the fan to “auto.” The “auto” setting for the fan ensures that the fan only turns on when the system is running a heating cycle. If you leave the fan set to “on,” the fan will blow even when there’s no heat being transferred into your home. The fan’s “on” setting will blow room temperature air most of the time. Now you can program the thermostat to your preferred temperature.

If you have any questions about how heat pumps work during the winter months of the year, contact us at Custom Comfort Air. We also offer reliable heating and air conditioning maintenance, repair, replacement and installation services. Our skilled technicians are also prepared to provide you with helpful indoor air quality solutions. For more details about heat pumps, give us at Custom Comfort Air a call.