What Is A Heat Pump?

Jan 02, 2018

What is a heat pump, and how does it work?


Eventually, over time, even the best heating and cooling system is going to die. You reach that tipping point where the maintenance and repairs, coupled with a sense of safety and reliability, make the new investment a smarter choice than propping up Old Faithful in your basement.
Heat pumps can offer an energy-efficient alternative to furnaces and air conditioners. What, you may be asking, is a heat pump? How does it work — and does it actually work? These are questions we get from Northern Virginia homeowners all of the time. 
Let’s take a look at heat pumps and help you decide if a heat pump system is right for you and your home.

What is a heat pump system?

Generally speaking, most HVAC systems generate temperature — that is, they’re going to create hot air in the winter to warm your home, or cold air in the summer to cool your home. Pretty straightforward concept, yes?
A heat pump is a little different. A heat pump is a mechanical-compression cycle refrigeration system that takes hot or cold air (depending on the season) from the outdoors and moves it inside your house.
Homeowners across the United States have used heat pump technology since the 1940s, and new advancements have allowed the use of heat pumps to expand into areas with extended periods of subfreezing temperatures as a legitimate space-heating alternative.

How does a heat pump work?

Pulling in heat from subfreezing temperatures? That sounds pretty odd, especially if you are a Northern Virginian experiencing the unforgiving cold of the 2017-18 winter. How does a heat pump work?
Here we go, with a huge assist from Allison Bailes of Energy Vanguard, who helped simplify what is a fairly complex process:
A basic concept of refrigeration, as Ms. Bailes writes,  is that “(h)eat flows when you have a temperature difference.” If you want to heat cold air, you essentially have to place it in contact with something even colder. A little counterintuitive, yes, but hang in there.
In a heat pump, refrigerant — a chemical mixture that absorbs heat from the air — is pushed through an expansion valve. This lowers the temperature of refrigerant. This, in turn, lowers the temperature of your heat pump system’s outdoor coils, which then makes the cold outside air warmer than the coils themselves. 
Now — remember your high school science and the Laws of Thermodynamics! — Ms. Bailes notes that “heat likes to move from warmer objects to cooler objects,” which means the cold outdoor air is actually able to heat the even colder refrigerant, and then the heat is swooshed back into your home. 
The heat pump is essentially an energy transporter — it constantly moves warm air (even when that air is initially pretty cold from one place) to another as needed. 
There are two main types of heat pumps. Here’s how a heat pump works for each:
  • Air-to-air: The most common, an air-to-air heat pump collects heat from the air (as we explained in the example above). Some manufacturers also produce ductless versions called mini-split heat pumps for homes without ducts, and reverse cycle chiller options that can be used with radiant floor heating systems.
  • Geothermal: Similarly, ground-source geothermal heat pumps collect heat from the nearby ground and water heat pumps do the same with, well, water. These units may cost more to install but often have lower operating costs since they take advantage of relatively constant ground or water temperature. Homeowners can also use geothermal or water heat pumps in more extreme climates than air source heat pumps. In order to determine if a geothermal heat pump is right for you, contact a trained heating and cooling expert.
Heat pump technicians often must install two distinct components for the system to work: an indoor unit, known as the air handler, and an outdoor unit — the heat pump — that works similar to a central air conditioner. As the heat travels between the indoor and outdoor units, a compressor circulates refrigerant that absorbs and releases heat.


What are the benefits of a heat pump?

Each year, more and more individuals are choosing to heat and cool their home with heat pumps. Here are some of the reasons why they’re making the switch:
Reduced costs. We know you’re curious: how much does a heat pump cost to operate? Because heat pumps move, rather than generate, heat, they can offer space conditioning with as little as one-quarter of the cost it takes to operate conventional heating or cooling appliances.
Efficient heating. Some companies manufacturer heating pumps for high-efficiency use. These units dehumidify better than a standard unit, further increasing your savings in the warmer months. 
Less fuel consumption. Because electricity powers the unit, homeowners with a heat pump can save substantially on fuel consumption. There’s also no risk of carbon monoxide poisoning while using a heat pump.


The disadvantages to heat pumps

There have to be some disadvantages to using a heat pump, or else everyone would have one, right? Fair enough. Like any heating and cooling option, there are some drawbacks. Some disadvantages to heat pump systems include:
Supplemental heating. In general, heat pumps work best in moderate climates. When it comes to very low temperatures, some homeowners may need a supplemental heating source. These options can range from anything to supplemental electrical heating to oil burners or an adapted gas furnace.
Additional noises. Because heat pumps distribute air by fan, the unit may case some noise and draughts that you’re not used to with a traditional HVAC unit.
Reliance on power. While the use of electricity (as opposed to fuel) is certainly a bonus for some homeowners, the downside is that the unit won’t work if there’s a power outage.


Let’s talk heat pumps.

Still have questions about how a heat pump works? Wondering how much does a heat pump cost for your home? Let's talk about how our five-star Warrenton heating and cooling technicians can help you make the best decision for your unique situation. Give us a call at 1-877-740-6657 or contact us online today.