Choosing the right heat pump for your home is a huge decision, one that you’ll likely have to live with for the next 20 years or more. When you have an existing home with forced air ductwork, your biggest concern is most likely how much more efficient your new system will be in comparison to your existing furnace, but there are many more features to consider.
For example, do you want the system to do cooling as well as heating? What about domestic hot water heating, if you could buy a system that could help you save money on your hot water heating cost – would you? What about noise levels outside of the home, general system longevity, and ability to tolerate cold weather? Beyond these basic considerations are other, long-term considerations like being able to go off-grid or connect your system to solar panels, and then there’s the environmental factor: do you want a heating system that is unhealthy and bad for the environment?
These are all considerations that need to be taken into account, so let’s go through them, one by one, but first let’s look at your options for forced air heating and cooling if you are considering a heat pump.
There are two primary types of heat pumps that will deliver forced air heating and cooling into your home. The first is a geothermal heat pump, such as our water to air heat pump, also known as the R Series. The second is an air to air heat pump, like our ATA Series heat pump. Let’s take a look at the considerations I listed above, and compare how each heat pump stacks up.
The main difference between a geothermal heat pump and an air source heat pump is the upfront cost to install one, and this stems from the heat collector system that each heat pump uses. Geothermal heat pumps use the warm earth beneath our feet to heat and cool your home. This is done by using a series of plastic pipes buried at least six feet beneath the surface of the earth. The pipes have a fluid circulating through them which absorbs the heat in the earth and, using a series of heat exchangers and a compressor, transfers the heat into your home in the form of hot air. The process is reversed in the summer time to provide cooling.
While this is an extremely efficient way to heat your home, it does involve excavating your backyard and laying horizontal piping, or drilling a water well, or drilling deep boreholes and laying pipe vertically. As you can imagine, this is not inexpensive, so the upfront geothermal heat pump cost needs to be considered.
Air source heat pumps, on the other hand, gather their heat from the outdoor air. They do this using an outdoor unit that collects the heat using a heat exchanger. The heat is transferred via refrigerant to the indoor unit, where using an additional heat exchanger and compressor, the heat is then transferred to the air and used to heat your home.
With an air source heat pump, there is no drilling or excavation required. Instead, the outdoor part of the heat pump sits on a concrete pad just outside of your home, as illustrated in the picture below.
Since there is no excavation required, the air source heat pump is more economical to install up front.
Forced air heating and cooling is a broad term use to describe any heating and cooling that is delivered to your home in the form of hot or cold air. There are many different types of heating systems that will deliver hot or cold air into your home, and most of those systems will do so using different air volumes and temperatures. Air source heat pumps and geothermal heat pumps both produce hot air and cold air in about the same temperature range, so there is not a big difference in their ability to heat and cool your home.
They also provide domestic hot water preheating via a built-in desuperheater, which will save you about 50% on your domestic hot water heating costs. Both our geothermal and air source heat pumps have a desuperheater as standard equipment, which is unheard of in most competing air source heat pump products.
A heat pump’s efficiency is how much heat it can produce compared to the energy required to run it. We measure a heat pump’s efficiency using a formula called coefficient of performance (COP). A heat pump’s COP is a measure of the heat pump’s output compared to the amount of energy required to produce that output. You can calculate heat pump COP by measuring its inputs and outputs in a laboratory setting, and we’ve measured that the average geothermal heat pump has a COP of 4.00.
In contrast, Air source heat pumps have a COP that goes up and down as the outdoor air (their heat source) fluctuates in temperature. We plotted the air source heat pump effective temperature range on a graph that can be seen below:
As you can see, the geothermal heat pumps have a high efficiency while the air source heat pump can have a very high or low efficiency depending on the outdoor air temperature. A geothermal heat pump will always be more efficient than an air source heat pump over the course of an entire year.
We now know that, on average, an air source heat pump is less costly to install up front, but what about the month to month costs? Again, this is where efficiency comes in.
We know that air source heat pumps are a little less efficient on average than a geothermal heat pump. That means the air source heat pump needs to work harder to put out the same amount of heat. When the heat pump works harder, it consumes more electricity, which will make it a little more expensive to run than an R Series heat pump.
If you choose an air source heat pump to replace your current heating system, you can expect a less dramatic reduction in your utility bills, especially in the dead of winter when temperatures are very low, and the unit may have to run on backup heat for a few days per year, which has a COP of 1.0.
Because geothermal heat pumps are housed completely indoors and underground, they last a long time. All of the major components are inside the home in a temperature-controlled environment such as a basement or mechanical room. You can expect your geothermal heat pump to last up to 20 years.
In comparison, air source heat pumps also have very good longevity, with a few caveats. Our uniquely designed air source heat pumps have all major components indoors including the compressor and control board. The only parts that are in the outdoor unit are an air coil, electronic expansion valve, and fan. While we manufacture our outdoor unit out of the most robust components we can find, they are subject to the wear and tear of the outdoor elements. They should still last a long time, but some maintenance will be required on the outdoor portion of the machine.
Both types of heat pumps are designed to provide extremely comfortable heating and cooling for your home. With both systems, you will receive the same, highly comfortable ducted heating in your home. In this respect the two heat pumps are equal.
Find out how a heat pump system could help you save on your monthly utility bills. Find a dealer for a free, personalized quote!