How a Heat Pump Water Heater Works
Energy-efficient appliances are key to lowering household energy bills and carbon footprint. Upgrading to an ENERGY STAR® heat pump water heater is one way to do this.
Unlike traditional water heaters, hybrid units use electricity to move existing heat rather than generating it directly. Several factors affect how well a heat pump works.
1. Energy Efficiency
In addition to being more environmentally friendly, a heat pump water heater also saves you money on your electricity bill. A typical ENERGY STAR HPWH cuts water heating energy costs for central Maine families by over 50%, with a payback period of about three years.
The technology behind a heat pump water heater is simple. Instead of burning fossil fuels, which produces harmful greenhouse gases, it uses renewable energy (i.e. wind, solar, hydro) to provide you with hot water. Its energy factor is also a lot higher than traditional electric tank models, making it more efficient and cost effective.
A heat pump water heater can be used in any home and does not require a chimney or venting system, unlike conventional gas and electric models. While it does produce a little more heat loss than other types of water heaters, this is less than the energy lost in cooling the refrigerant.
Because of their high energy efficiency, a heat pump water heater uses considerably less electricity than other types of electric tanks and is one of the most environmentally friendly appliances you can own. This makes it a popular choice for households seeking to lower their energy consumption and reduce their carbon footprint. Many utilities, local governments, and ENERGY STAR rebates offer incentives for heat pump water heaters to help offset their upfront costs.
Water heating accounts for a large percentage of your household’s energy consumption. Compared to conventional fuel or electric water heaters, heat pump models use less energy and therefore reduce your electricity bills. This makes them a smart investment.
To work, a heat pump water heater uses the same principle as an air conditioner. Surrounding air is drawn into the unit through a series of heat pump water heater refrigerant-filled tubes and a fan. Once the refrigerant picks up heat, it’s pumped to the upper portion of the system and then to the storage tank. This process is repeated continuously.
Once the water is hot, it’s transferred back to the lower portion of the system where it’s blown away with the fan. This cools down the refrigerant, and the cycle begins again. The energy savings that a heat pump water heater offers are substantial. It’s estimated that a two person household can save up to $174 a year and an entire family can save up to $435.
While many utility companies offer rebates to help bring the cost of a heat pump water heater down, the upfront cost is still higher than traditional gas or electric models. It’s important to consult with an expert contractor who can advise you on the best model and brand for your household. This includes consideration of your home’s layout, climate conditions and usage patterns.
3. Water Temperature Control
During operation, the heat pump water heater uses an efficient fan that draws in ambient air from around the unit. The refrigerant is then drawn into the compressor and evaporator coils where it becomes heated. The heat from the evaporator is then transferred to the water tank through the condenser coils. The water heater’s control panel gives you the option to choose among four different modes. Depending on your needs, you can select between a Heat Pump Mode that maximizes energy savings, a Hybrid Standard Mode that balances energy savings with hot water recovery speed or a Vacation Mode that stops the fan, the heat pump and the flow of cold air for maximum efficiency while you are away.
The heat pump water heater’s ability to operate depends on the temperature of your home and municipal water supply. As outdoor temperatures decrease, the heat transfer from ambient air will become less efficient, or may stop altogether. If that occurs, the backup electric heating elements will come on to bring the water to your desired temperature.
Some homeowners struggle with balancing their desire to lower their hot water temperature for energy savings with mitigating risk of scalding. For these homes, a water tank booster is an excellent solution. It can keep your hot water at heat pump water heater a high 140degF for safety and then mix in some colder water to make sure you always have an adequate supply of hot water at your taps.
The evaporator coils on a heat pump water heater pull in ambient warm air from around the unit and use it to raise your home’s hot water temperature. They also work as part of a combined heating and cooling system to heat and cool your house.
Like any appliance, you can install a heat pump water heater yourself. However, we recommend hiring a plumbing and heating contractor to install your HPWH to make sure it’s installed properly and safely. The installation process requires electrical and plumbing connections. It’s important that the hot and cold water pipes are insulated to reduce energy loss. We typically use polyethylene or neoprene foam pipe sleeves for this purpose.
If you have a space available in your garage, basement, mechanical room or other unheated area of your home to install the HPWH, that’s usually the best choice for location. Many Colorado utilities, including Xcel, offer $600 – $800 rebates for HPWH installations. Boulder and Boulder County residents can take advantage of additional incentives from the local utility, along with a federal tax credit via the Inflation Reduction Act.
Whether you’re concerned about the environment or just want to bring down your water heating costs, a heat pump water heater is a great solution for your home. With significant incentives offered by most major utilities on the west coast, a new heat pump water heater can cost less than installing a standard electric tank water heater.