Summer is just getting started, and already parts of the country have been scorched by record-breaking temperatures. Air conditioning units previously little-used are being overtaxed. As a result, many places, including several in Virginia, are looking at heat pumps as a cost-effective and environmentally friendly solution. Policymakers are jumping on the bandwagon too.
Why the growing interest?
Following last year’s heat wave across the Pacific Northwest, deemed a “mass casualty event,” the press for a solution for areas previously unaffected by heat waves increased. This year, however, the war in Ukraine has introduced heat pumps as a way of helping European countries dependent on gas and oil for heating ahead of this year’s winter.
Of course, decarbonization of our atmosphere is essential to reducing the effects of global warming. A report by home energy research firm Carbon Switch estimates that switching U.S. single-family homes to heat pumps could save 142 million metric tons of carbon each year.
In the U.S., experts have also emphasized that reducing America’s dependence on oil and gas is critical to national security.
As heat pumps can do double duty by both heating and cooling, this makes them an ideal way to address multiple needs.
Challenges to Global and Local Conversion
As the world tries to electrify everything and reduce carbon pollution, hurdles still remain. Supply chain issues are ongoing as the world recovers from the pandemic, Congress also needs to pass the HEATR Act for any converting benefits to make it to heat pump-curious homeowners, and our infrastructure needs to be upgraded to handle the increased demand for electricity this and other initiatives will demand.
As Carbon Switch founder Michael Thomas puts it, “The solution … isn't to keep using fossil fuel heating. It's to build more renewables and capacity,” Thomas said. “That's why it's so important that we increase the production of renewables and do everything we can to get around NIMBYs and utility lobbying, all this stuff that's really holding the grid back.”
So How do heat pumps work?
There are several types of heat pumps that derive their cooling and heating abilities from a variety of sources.
Air Source
All heat pumps work by using a small amount of energy to move heat from one location to another. This means that rather than burning fuel to create heat, the device moves heat from outside of your home in winter to the inside, and in the summer, it removes the warm air from the inside and pulls air from the outside into the home, passing it over cooling coils.
Ground Source
Also known as geothermal, these types of heat pump absorb heat from the ground or an underground body of water and transfer it indoors, or vice versa.
Absorption Heat Pump
Used primarily for industrial or commercial uses, an absorption heat pump is powered by gas, solar, or electricity. Instead of compressing a refrigerant, these devices utilize an absorption pump that absorbs ammonia into water, and then a low-power pump pressurizes it. The heat source then boils the ammonia out of the water, and the process starts all over again.
Mini-Split Heat Pump
A mini-split is used when there is no ductwork to move air around the home . They won't move as much air as larger heat pumps, so they are best for small living and commercial spaces.
Cold Climate Heat Pump
A relatively new addition to the heat pump line up, cold climate heat pumps can efficiently handle colder weather than most other designs — even below 0 degrees Fahrenheit. The pump detects the minimum amount of energy needed to provide the desired level of heating or cooling and adjusts its output up or down, so it never wastes energy.
In the cold winters of Minnesota, these heat pumps have been shown to be about twice as energy-efficient as the typical natural gas furnace, making them an extremely green alternative.
Pros and Cons of Heat Pumps
Those of us who rely on heat pumps for heating and cooling know that in the middle of February when temperatures fall below freezing on most nights, a heat pump doesn’t do much to keep you warm and toasty, although innovators are working to improve upon this.
Those used to the intense heat that oil and gas furnaces can produce may be disappointed by the less intense heat of a heat pump. An extra layer or two of clothing helps address the difference.
Before installing a heat pump, you'll need to consider what kind of supplemental or backup heating you may need to use when the heat pump can't work efficiently. Many heat pumps use supplemental electrical heating, but you might also use an oil burner or an adapted gas furnace. Whatever type of heating system is common in your area is likely the most efficient and cost-effective backup method. You can always call your local utility company for information.
Ground-source heat pumps are better dehumidifiers than normal air conditioners, because these systems typically have larger, flat return coils that condition and dehumidify more air than the corresponding coil in an air conditioning system. Air-source heat pumps have about the same dehumidifying capabilities as air conditioning systems. If you have any humidifying or dehumidifying needs, take this into consideration.
How do you heat your home? Would you consider switching to a whole-house heat pump system? We’d like to know.
Sources: How Stuff Works, Protocol, Green Match, Foreign Policy.com