Efficient heating and cooling by moving heat between air, ground, water, refrigerant loops, buildings, and hot water systems
Heat Pumps
Heat pumps heat and cool buildings by moving heat rather than making heat by burning fuel or using electric resistance. They can draw heat from outdoor air, the ground, or water, then deliver it indoors or into hot water. Their climate value depends on efficiency, building insulation, refrigerants, electricity sources, installation quality, and grid planning.
What they are
A heat pump is a machine that transfers heat from a cooler place to a warmer place by using electricity. In heating mode, it extracts heat from outdoor air, the ground, or water and moves it indoors. In cooling mode, many systems reverse the process and move heat from indoors to outdoors, like an air conditioner.
How the cycle works
Most heat pumps use a refrigerant that evaporates and condenses as it moves through coils, a compressor, an expansion valve, and sometimes a reversing valve. The refrigerant absorbs heat at low temperature and releases it at higher temperature. The compressor supplies work that makes this movement against the natural heat flow possible.
Air-source systems
Air-source heat pumps exchange heat with outdoor air and are the most common type for homes. Ducted systems use existing or new ductwork, while ductless mini-splits serve individual rooms or zones. Cold-climate models can work in low temperatures, though performance, backup needs, and sizing depend on the building and local climate.
Ground and water sources
Ground-source, often called geothermal, heat pumps exchange heat with the stable temperature of the ground through buried loops or wells. Water-source systems exchange heat with wells, lakes, or other water bodies. These systems can be very efficient, but installation is more site-specific and often more expensive upfront.
Buildings matter
Heat pumps work best when the building is suitable for them. Insulation, air sealing, duct quality, radiator size, airflow, controls, and hot-water temperature all affect performance. A poorly sealed or badly installed system can disappoint, while a well-designed system can improve comfort and reduce energy use.
Climate and electricity
Heat pumps can cut emissions when they replace fossil-fuel heating, especially as electricity gets cleaner. They also add winter electricity demand, so grids may need upgrades, flexible controls, thermal storage, and efficiency improvements. Refrigerants can be powerful greenhouse gases, so leakage and refrigerant choice matter too.
Costs and adoption
Costs depend on equipment, building type, electrical work, duct changes, labor, incentives, and whether the system also replaces air conditioning. Operating cost depends on local fuel and electricity prices. Adoption often depends on trained installers, consumer trust, financing, landlord-tenant rules, and clear information.
Why it matters
Heat pumps matter because heating buildings and water is a major energy use. They offer a practical path to efficient electrification, especially when paired with insulation and clean electricity. They are not a single product that solves every building, but they are one of the most important tools for reducing heating emissions.