Climate change has recently led to unprecedented heat waves in areas with typically temperate climates, such as the United Kingdom and the Pacific Northwest of the United States. Often, residents of these regions have never had to use an air conditioner, but heat waves have spurred the need for home cooling systems.
Electric heat pumps offer a potential solution, as they can be used to cool buildings with far fewer carbon emissions than air conditioning. Here is a closer look at how heat pumps work and how they could help world governments reach their net-zero carbon emissions goals.
How Do Heat Pumps Work?
At first, heat pumps may seem like a counterintuitive solution to heat waves. However, an electric heat pump is similar to an air conditioner, with the main difference being that air runs in two directions: inside and outside of the home. This means heat pumps can be used to cool homes during the summer and bring heat into the home during the winter. They can also be used to bring hot water to buildings in some situations.
Heat pumps extract heat from low-temperature areas (known as sources) to high-temperature locations (called sinks). Homes and other buildings can function as either sources or sinks. When energy is extracted from a source, the temperature drops. Conversely, adding energy to a sink causes the temperature to increase.
In the summer, the home is used as a source, and thermal energy is removed from inside the home and pumped outside, which cools the home. The home functions as a sink during cold temperatures, as thermal energy is added to the interior space to provide heat. Heat pumps are fully reversible and can be used year-round for heating and cooling needs.
Types of Heat Pumps
Heat pumps generally fall into one of the following four categories:
- Ducted Air-Source – Homes with ducts may be outfitted with three types of ducted heat pumps: air-to-air, geothermal, and water source. Air-source heat pumps transfer heat between buildings and the air from outside.
- Ductless Air-Source – Also known as mini-split heat pumps, ductless heat pumps function the same way as ducted air-source heat pumps. Another option for ductless homes is the reverse cycle chiller, which produces hot and cold water instead of air, allowing it to be used with radiant floor heating systems.
- Geothermal – Also known as ground-source or water-source heat pumps, geothermal pumps transfer heat between buildings and either the ground or a nearby water source. They are more expensive than other heat pump options, but they are also much more efficient and have lower operating costs.
- Absorption – The absorption heat pump (AHP) is a relative newcomer to the field. Also known as gas-fired heat pumps, AHPs use heat or thermal energy as an energy source. Many different types of heat sources, such as natural gas, air, solar-heated water, and geothermal-heated water, can be used with AHPs.
Heat Pump Programs in the UK
The UK has been attempting to encourage heat pump use long before the 2022 heat waves. Like many nations, the UK has goals to cut greenhouse gas emissions, and the government previously provided subsidies for heat pumps that only produce heat. Although these subsidies have been discontinued, British homeowners may still apply for funds to install heat pumps that produce both hot and cool air.
The subsidy program, known as the Renewable Heat Incentive, paid Britons to use renewable heat sources such as heat pumps. However, homeowners could only qualify if their heat pumps had a mechanism installed that only allowed them to be used as heaters.
That program was replaced with a new incentive in which the UK government pays up to £5,000 of the cost and installation of an air source heat pump. The government hopes to install at least 600,000 systems by the year 2028.
Heat Pump Promotion in the United States
Americans in Pacific Northwest cities like Seattle, Washington, were forced to purchase their first air conditioners in the summer of 2022 due to historic heat waves. Energy experts and officials view this new demand for home cooling as an opportunity to introduce a large section of the US population to heat pumps.
Clean energy supporters want to see US lawmakers follow the UK’s lead and introduce subsidies and regulations that can help make heat pumps more affordable. In response to the summer’s heat waves, the city of Denver, Colorado, has released an emissions-cutting plan focused on heating and cooling. Officials have been discussing a program that helps residents install heat pumps when they need to replace their air conditioners or furnace.
First, we will need to overcome a variety of obstacles to make heat pumps the standard heating and cooling system. The technology is unfamiliar to many Americans, and policymakers will need to find a way to draft and pass legislation that facilitates the transition. However, the economic and environmental benefits far outweigh the difficulty of transforming our heating and cooling standards.