Hybrid electric water heaters have started to show up in plumbing aisles of home improvement and appliance dealers such as Home Depot, Lowes, and Sears since 2009. The most common heat pump water heaters featured at these retailers are models made by GE, Rheem, and A. O. Smith.
- GE GeoSpring – Available as a 50 gallon model with an energy factor of 2.4EF
- Rheem HP-50 – Available in 40 and 80 gallon models with an energy factor of 2.0EF
- A.O. Smith Voltex® – Available in 60 and 80 gallon models with an energy factor of 2.4EF
Did you know that the efficiency (measured as energy factor) of the water heaters above is determined in a fictitious laboratory climate that never drops below 68 degrees Fahrenheit?
Are you aware that the posted efficiency ratings (measured as energy factor) on these products are reduced with every degree the ambient temperature in your garage or basement is reduced?
The truth is that most heat pump water heaters stop producing hot water in the efficient heat pump mode if the surrounding air from which the heat pump water heater draws air drops below 40-45 degrees. This means that a heat pump water heater installed in a garage or basement in a colder climate will only be an expensive electric water heater providing none of the efficiencies that you may have been promised by your contractor, retailer, or in manufacturers’ brochures.
Hybrid electric water heaters are efficient because they transfer heat from the air to the water that is stored in the tank. The colder the temperature gets, the more time the heat pump water heater needs to generate its next batch of hot water. A 50 gallon hybrid electric water heater promising to generate 60 or more gallons of hot water per hour may not be able to get the job done in the heat pump, economy, or efficiency mode. It may have to use back-up elements to keep up with the hot water demands of a family taking back to back showers in the morning. The use of back-up water heating elements eliminates or reduces the efficiency and cost savings generated by the water heater. Ideally, every heat pump water heater will be able to maximize its ability to generate efficient hot water in heat pump mode. This is what drives energy efficiency and home owner benefits.
Most water heater manufacturers have responded by simply making a bigger hybrid electric water heater tank. The big tanks have up to 80 gallon capacity. In theory, the increased capacity allows the water heater to operate for longer periods in heat pump mode since it will not be out of hot water as quickly as with a smaller tank. This reduces the pressure on the equipment to use its back-up electric elements.
The larger tank sizes will also help with reduced efficiencies when ambient temperatures drop. The increased capacity will act as buffer. However, an 80 gallon tank may really behave like a 50-60 gallon tank from an efficiency perspective when temperatures are getting close to the heat pump water heater’s cut-off point at which it is forced to shut down its heat pump compressor.
This situation is a major issue for electric powered homes without access to gas water heaters situated in colder climates as they may not be able to take advantage of energy efficiency benefits generated by heat pump technology. They may have to stick to conventional technology.
To eliminate these concerns about heat pump water heaters, AirGenerate introduced the AirGenerate AirTap™ Hybrid water heater. AirGenerate hybrid electric water heaters are available in 50 gallon (ATI50) and 66 gallon (ATI66) models. Both models operate down to ambient temperatures of 20 degrees Fahrenheit in heat pump mode without use of electric back-up elements.
The 20-25 degree Fahrenheit difference in the operating range for AirGenerate products compared to its competitors allows AirGenerate AirTap Hybrid water heaters to work in heat pump mode throughout the year while its competition is forced to rely on the backup electric elements in colder climates, eliminating the product’s energy efficiency.
AirGenerate AirTap™ Hybrid water heaters are specialty products made to produce efficient hot water in just about any climate in the United States of America. AirGenerate water heaters are available in all regions of the continental USA.