What is a heat pump?
Updated: May 4
Similar to an air conditioner, a heat pump can cool your home during the warmer summer months. However, they also have a reversing valve that allows you to heat your home during cooler winter months. A heat pump can provide year-round heating and cooling in an all-in-one system.
There are three main types of heat pumps: air source, water source and ground source (geothermal). All three of these operate on the same principles, except they gather their heat from different sources.
Air-source heat pumps are the most common. This type of heat pump extracts heat from the outside air and moves it into your home in the winter. In the summer it removes heat from the air in your home, and sends it outside. When properly installed, an air-source heat pump can deliver up to three times more heat energy to a home than the electrical energy it consumes. This is possible because a heat pump transfers heat rather than converting it from a fuel, like combustion heating systems.
Types of Air-Source Heat Pumps
Ductless vs. Ducted
Ducted systems distribute the heated or cooled air through a ductwork system. Ductless systems have no ductwork but require a three-inch hole through the wall to connect the outdoor condenser and the indoor heads. Ductless systems are often installed in building additions.
Split vs. Packaged
Most heat pumps are split-systems—that is, they have one coil inside and one outside. Packaged systems usually have both coils and the fan outdoors. Heated or cooled air is delivered to the interior from ductwork that passes through a wall or roof.
Multi-Zone vs. Single-Zone
Single-zone systems are designed for a single room with one outdoor condenser matched to one indoor head. Multi-zone installations can have two or more indoor coils connected to one outdoor condenser.
In the summer months, a heat pump works just like a standard air conditioner would. Standard air conditioners, use a refrigerant to absorb unwanted heat in your home and transfer it to the air outside. This happens by changing the pressure of the refrigerant fluid. At low pressures, the refrigerant will absorb heat available in the air and evaporate from a liquid to a gas. At high pressures, the gas refrigerant is higher energy than the outside air, so it passes heat to the surrounding air and the refrigerant condenses back to a liquid when it cools. By controlling the pressure of the refrigerant, an air conditioner can extract heat from your home, even on very hot days.
In the winter, a heat pump uses this same cycle “run in reverse” to extract heat energy from the outside and transfer it into your home. Even when it’s really cold out, there is still some amount of heat energy in the air. Because the outdoor air has higher energy than the cold, low-pressure refrigerant, the refrigerant absorbs that heat and evaporates. Just like the air conditioning cycle, the gas refrigerant can be pressurized, which raises the temperature. When the refrigerant is piped back into your home, it is used to warm up the air inside. The heat is extracted and it condenses back into a liquid, and the cycle continues.
How Does a Heat Pump Save Energy?
Because it moves heat from one place to another rather than generating it, a heat pump uses less energy to warm your home than a conventional electric or gas system. If you are replacing a central air conditioning system, heat pumps can work with the existing ducting in your home or are available as “ductless,” units, if your home does not have ductwork.
One of the key advantages to an electric heat pump is the efficiency with which it operates. In certain warmer climates, heat pumps can be the sole source of winter heat. Although heat pumps can pull heat from the air even in incredibly low temperatures, it takes more energy to do so. This can make them less efficient than a standard gas or electric furnace when the weather is really cold. Many Colorado homes with heat pump systems have a backup source of heat for very cold days or long periods of low temperatures when the heat pump system is inefficient. These backup sources can be oil, gas, propane, electric or pellet.
For climates that do experience winter days that get below freezing, homeowners are advised to purchase a heat pump with heating elements in order to help the home stay warm on colder days. The heating elements activate when the outside temperature drops below a certain temperature.
What are SEER and HSPF ratings?
A heat pump’s cooling efficiency is indicated by the seasonal energy efficiency ratio (SEER), which is a measure over an average cooling season of the total heat removed from the conditioned space, expressed in Btu’s, divided by the total electrical energy consumed by the heat pump system, expressed in watt-hours. The higher SEER ratings indicate better energy efficiency than lower SEER ratings.
However, when purchasing a heat pump, it is important to also look at the HSPF rating. HSPF stands for heating seasonal performance factor. The measure over an average heating season of the total heat provided to the conditioned space, expressed in Btu’s, divided by the total electrical energy consumed by the heat pump system, expressed in watt-hours. Like SEER ratings, the higher the HSPF rating, the more efficient the heat pump. In general, homeowners should look for heat pumps with HSPF ratings of 5 or higher.
In warmer climates, SEER is more important than HSPF. In colder climates, focus on getting the highest HSPF feasible.
So, is a heat pump a good idea?
It will certainly depend upon your particular situation. Your initial heat pump cost for installation will be significantly higher than other heat sources but it’s also significantly more energy-efficient. A heat pump is generally considered one of the most efficient heating solutions on the market. If you’re switching from an electric furnace, the heat pump can reduce your utility bill by a third or more. It can also double as an air conditioner meaning you’re getting heating and cooling in one unit.
We would be happy to answer any questions you might have or make a visit to evaluate your situation for the installation of a heat pump system. Just give us a call.