If you live in a climate like Denver, Colorado, a heat pump can be an excellent way to efficiently heat and cool your home. A heat pump essentially shifts warm air from one area to another. It usually consists of an indoor air handler and an outdoor component that utilizes a compressor to absorb and release heat travelling between the indoor and outdoor components. These pumps move heat versus generate it, costing much less to operate than a standard HVAC closed-loop system. We’ll get into the nitty gritty of how a heat pump works so that you can make the most educated decision when choosing how to invest into cooling and heating your home.
Before getting started, here’s a common question we hear from homeowners. “How is a heat pump different from a furnace?” Furnaces burn fuel to generate heat. A heat pump extracts heat energy from the air passing through it.
How does a heat pump work?
Heat pumps work by moving heat energy. Even in cooler air, there is heat that can be shifted into the home to raise the indoor temperatures.
- When the home needs to be cooled, the heat pump can shift the heat energy from the home to the outdoors.
- The refrigeration system for a heat pump is made up of two coils of tubing, one on the outside, and one indoors, a compressor, and aluminum fins to facilitate the transfer of heat.
- When the heat pump is warming, the refrigerant in the outside coils extracts airborne heat energy and evaporates into a gas as it warms.
- As it passes into the indoor coils, the heat is then released from the refrigerant as it cools and liquifies again.
- For cooling, the process can be reversed.
Different types of heat pumps
There are several different kinds of heat pumps and the most commonly used is an air-source style heat pump. Commonly paired with a home with ducting, this transfers heat between your home and the outside environment. These systems can reduce the amount of electricity used by as much as 50%. Pretty good cost savings! They are effective at reducing humidity, even more so than some typical air conditioning systems. New technology advances for these systems make them more versatile than in the past. In temperatures where winters are cold, heat pump systems are installed to augment an existing heating source or to work in conjunction with other systems. Most heat pumps will utilize an electric resistance heater as a back-up source in cold weather but they can also be equipped with burners, such as a combustion system using propane, natural gas or wood.
Components of these systems that make them more efficient than previous technology include improvements on the design of coils and compressors. Expansion valves allow more control of refrigerant between the indoor and outdoor coils, and variable speed blowers heighten the efficiency of the components. Variable speed blowers or dual-speed motors keep the air within the home moving more slowly than a forced-air system. The variable speed prevents drafts and makes the unit far more efficient.
Some units even have the means to heat water using waste heat from the heat pump’s cooling mode. This technology is called a desuperheater, and can heat water more efficiently than a standard water heater.
Older homes or homes that don’t have ducts can utilize what’s called a mini-split heat pump to augment heating systems. A mini-split pump is also ideal for tiny houses or other highly efficient builds. These also use the outdoor compressor and interior air-handler setup. Many mini-split heat pump systems allow for multiple interior air handlers, allowing the homeowner to create zones with individual thermostats. This kind of set-up can be extremely efficient as it makes it easy to heat or cool only the areas that are occupied. The mini-split heat pumps are very efficient as they don’t experience the energy loss that occurs when air is passed through ducts. They are easy to install and highly versatile. It’s critical to hire a qualified installer or technician when putting in a mini-split heat pump as they have very specific requirements to be met during both planning and installation.
Positives and negatives of a heat pump
Like any system, a heat pump system does have its strengths and weaknesses. Fans and compressors can make noise and should be located accordingly. Noise-absorbing bases and surrounds can be used for a heat pump system. These units should be installed away from high levels of wind or airflow. Heat pump systems have to have specific levels of refrigerant charge and airflow for them to work well. Mini-split heat pump systems are more likely to require regular preventative maintenance checks by a qualified technician who works with refrigerant. It may take a little time to get the system tweaked just right for each home.
The efficiency for these pumps is measured by the HSPF, or Heating Season Performance Factor and the SEER, or Seasonal Energy Efficiency Ratio. HSPF is calculated by the space heating needs required during the season (measured in Btu) divided by how much electrical energy was consumed (measured in watt-hours) during the season the unit was heating the home. SEER is calculated by the total heat that the heat pump removed from the home during the warmer season (measured in Btu), divided by how much electrical energy it took to power the pump, which is also measured in watt-hours. When choosing a heat pump, consider your climate. For warmer climates, the SEER rate will be more important than the HSPF rate for obvious reasons.
Heat pump systems are an outstanding option to consider even for areas of the United States that have colder winters. A lot of our clients here in Denver, Colorado use heat pumps. While the initial investment is higher and need for professional installation may be a concern for the homeowner, the potential for long-term energy savings and increased efficiency could pay for itself in a short period of time.