Heat pump glossary

Cold climate heat pumps – also called extended capacity or hyper heat pumps – are most efficient but also most expensive. They extract heat exceptionally well even when it's minus-5 to minus-12 degrees, depending on the model. Sean Meagher/The Oregonian

Ducted heat pump: A heat pump that uses ducts. If you have a furnace with existing ducts running through your house – assuming those ducts are in good shape — you can switch to a ducted heat pump system.

Mini-split heat pump: A ductless heat pump. Its outdoor unit is connected to the indoor unit using thin copper pipes. Depending on the size and configuration of your space, you can choose to have one or multiple indoor units heating/cooling one or multiple areas of the home using the same outdoor unit. Because a mini-split controls temperature in a specific area of a home, it's also a good solution for heating/cooling a finished attic room, basement or sunroom.

Cold climate heat pump: Also known as an extended capacity heat pump or inverter heat pump. It's capable of heating your home when temperatures drop below freezing. Because heat pumps are relatively new in the U.S, the Energy Department two years ago launched a manufacturers’ challenge to develop and widely commercialize high-performing cold climate heat pumps in the U.S. and increase their capacity to work in very cold climates. Now, the most popular manufacturers are the Japanese brands Mitsubishi, Fujitsu and Daikin. Note: Most heat pumps on the market are standard, not cold climate ones, and require backup heat such as a gas furnace or electric heat strips when temperatures fall.

Heat strips: Installed inside air handlers in many heat pumps as backup heat. They’re not very energy efficient, but act as an emergency heat source when temperatures drop below freezing. In very cold climates, when a heat pump goes into defrost or struggles to heat, the strips can kick in to provide temporary heat to the home.

Portable heat pump: A heat pump that stands on the floor inside your home, with one or two hoses running through a window. It can be easily installed but its ability to work during cold snaps is limited.

Compressor: The outdoor part of a heat pump, typically installed on top of a concrete pad. Also known as a condenser, the outdoor unit holds the compressor and condensing coil.

Air handler: The indoor part of a heat pump system, most often located in the attic, basement or a dedicated closet. It typically resembles a gas furnace.

Head: The air handler for a ductless/mini-split heat pump. These small air distribution units are usually mounted high on the wall or are recessed in the ceiling. Depending on the number of heating zones you choose, you can install one (single-head) or more (multi-head) indoor units connected to the same outdoor compressor.

Efficiency rating: SEER stands for Seasonal Energy Efficiency Rating. It measures how energy efficient the heat pump is at cooling your home. Similarly, the Energy Efficiency Ratio (EER) measures cooling efficiency at a standard outdoor temperature, 95 degrees. The Heating Seasonal Performance Factor (HSPF) refers to the pump's efficiency at heating. Less common, Coefficient of Performance (COP) refers to heating efficiency for geothermal heat pumps. The higher the number, the more efficient the unit and the bigger the savings on your utility bills.

Geothermal heat pump: Also known as a ground source heat pump. It uses constant temperature below the ground to heat, cool and even provide hot water. It's a lot more efficient than a regular heat pump that uses air as a source, but also two to five times more expensive.

Water source heat pump: Extracts heat from a body of water – a river, lake or pond – and converts it into energy to heat a home. These are often more efficient than ground and air source heat pumps, but they require water – and the larger the home, the larger the water source needed.

Read more about heat pumps on The Oregonian/OregonLive's heat pump topic page.

– Gosia Wozniacka; [email protected]; @gosiawozniacka

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