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Serving Katy, TX and the Surrounding Areas

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Serving Katy, TX and the Surrounding Areas
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AC Comfort Blog

Does a Heat Pump Work Differently in Its Two Modes?

sun-and-snowflake-badgeHeat pumps are a popular option for home comfort here in Katy because they are ideally suited to our climate: hot weather during most of the year with a short, cool winter. A heat pump works as both an air conditioner and heater, able to switch between the two modes with only an adjustment on the thermostat. During hot weather, a heat pump is as powerful as an air conditioner of the same cooling tonnage. During colder weather, a heat pump delivers heat at lower cost than using an electric furnace.

But how does a heat pump do both jobs? Does it switch between different operations when it goes from one mode to the other?

The Trick that Makes the Heat Pump Work

The answer is that a heat pump works almost identically in cooling and heating modes. (We’ll get to the almost in a moment.) It isn’t two different systems, an AC and heater, packaged together in one unit. It’s a single system that uses the same components whether it’s called on to heat a space or cool it.

The trick that makes the heat pump work is a reversing valve. Think of a heat pump as a standard air conditioner, because in many ways it is the same as an air conditioner. A compressor puts refrigerant under pressure, then sends the hot refrigerant out of the coils to the outdoor coils, where it releases heat and cools down. The cooled refrigerant moves indoors, passing through a pressure expansion valve that further lower its temperature. The refrigerant then goes through the indoor coils and evaporates to absorb heat. After that, it returns to the compressor.

The reversing valve is a component in a heat pump that controls which direction the refrigerant goes after leaving the compressor. It doesn’t have to head to the outdoor coils first. If the valve switches where it goes so it heads first to the indoor coils, the whole operation of the heat pump changes direction. Now heat is being removed from outside the house and brought into it. The two sets of coils have swapped jobs. All it took was the reversing valve.

The Small Exceptions

We could stop it right there, because that’s the basics of how a heat pump works: change the direction the refrigerant moves to change whether it’s heating and cooling. But there are a few differences between the modes:

  • A heat pump uses less refrigerant in heating mode. The extra refrigerant is stored in a part called the suction line accumulator until needed for cooling again.
  • Because a heat pump must still allow the refrigerant gas to expand and drop in temperature, there is an additional pressure expansion valve.

These are small differences. For the most part, a heat pump works the same no matter the mode.

Are You Interested in Installing a Heat Pump?

If you are in a position where you’re ready to retire both your AC and heater, then a heat pump is an attractive choice for a replacement system. Heat pumps cost more than a standard AC, but save money when replacing both an AC and heater. Call us for heat pump services in Katy, TX!

At AC Comfort, we believe comfort can cost less! Interested in a heat pump installation? Call us today to schedule an appointment.

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