Long popular in Europe and East Asia, ductless heat pumps are increasingly gaining favor around the U.S. for their energy efficiency and convenience. With no ducts to waste energy or complicate installation, these systems are highly efficient, flexible, and space saving.
Considering the wide range of temperatures we see around Maryland and Delaware, it’s important to choose a system that can cool as efficiently as it can heat. This makes ductless heat pump systems particularly useful in our area because some reach efficiencies even higher than typical conventional ducted heat pumps.
Ductless Heat Pump Efficiency
As with any heating or cooling system, though, choosing the right one isn’t simply a matter of picking the highest-efficiency system you can afford.
To find the efficiency that’s right for your needs, it helps to understand the various efficiency ratings used for heat pumps. Ducted and ductless heat pumps receive two efficiency ratings: the seasonal energy efficiency ratio (SEER) and the heating seasonal performance factor (HSPF).
You’ll find these numbers, along with other efficiency information, on the heat pump’s yellow Energy Guide label.
The seasonal energy efficiency ratio tells you how efficiently a heat pump or air conditioner cools. The number is a ratio of the system’s cooling output during a typical cooling season divided by the total amount of electricity the system uses during the same cooling season.
The calculation accounts for variations in outdoor temperatures throughout the season using a pre-selected set of temperatures ranging from the 60s to more than 100 degrees. Temperatures used in the calculation are the same no matter where the ductless system was manufactured or where it will be installed. That means SEER’s accuracy varies depending on your geographic region.
The higher a system’s SEER, the greater its cooling efficiency. That means a ductless heat pump with a SEER of 20 costs less to operate than one with a SEER of 17. Generally speaking, however, higher efficiency ductless heat pumps have higher purchase prices, so you’ll want to balance your need for efficient cooling and low operating costs with your budget for new equipment.
Some older conventional heat pumps still in use have SEERs as low as 6, but as of June 2011, the federal minimum for newly manufactured heat pumps is SEER 13. Today’s most efficient ductless heat pumps reach SEERs of up to 30, but models with SEERs above 23 are still relatively uncommon. To stay comfortable in the sultry Baltimore summers and still keep your cooling bills low, look for a system with a SEER of around 18.
Related to SEER is an older, simpler measurement of cooling efficiency known as energy efficiency ratio (EER). Whereas SEER is calculated using a range of outdoor temperatures, EER is calculated using a constant outdoor temperature of 95 degrees. This provides a snapshot of the system’s cooling efficiency in one given moment. While often listed in a heat pump’s technical specifications, EER is useful primarily to heating and cooling professionals.
Because ductless heat pumps heat as well as cool, they receive a rating for their heating efficiency. This rating is the heating seasonal performance factor, which is a ratio of the system’s heat output over a typical heating season divided by the amount of electricity the system consumes during that season. A higher HSPF indicates greater heating efficiency.
As with SEER, HSPF is calculated using a range of outdoor temperatures, usually between the upper teens to the upper 40s, to account for weather variations throughout the fall and winter. Use of the defrost cycle and backup heating are also factored in because these two operational modes can reduce the system’s efficiency.
The current federal minimum for heat pumps manufactured today is HSPF 7.7. The most efficient systems currently made can reach HSPF 13 but, as with the highest SEER systems, ductless heat pumps this efficient aren’t common. To heat your home efficiently during the Baltimore area’s icy cold winters, look for a ductless system with an HSPF of around 10.
HSPF is related to coefficient of performance (COP), which is a ratio of the system’s heating or cooling output divided by the electrical energy it uses to provide that output. This is a measure of the system’s efficiency at one moment in time, rather than over a whole season. That means the actual COP of a system in use under real-world conditions depends greatly on the weather and other factors.
Understanding how these efficiency ratings are calculated helps, but when you’re shopping around for ductless heat pumps, you’ll also need to know how the systems compare with each other in terms of efficiency.
Energy Star Label
Energy Star is a program run by the Environmental Protection Agency (EPA) to identify and label home appliances and other home products, such as windows, that are among the top 15 to 30 percent most efficient in their class.
Minimum standards for Energy Star qualification are set by the EPA. Manufacturers have their products tested by an independent third-party laboratory, and products that meet or exceed the EPA’s standards qualify for the Energy Star label.
The current standards for air-source (conventional) heat pumps, including ductless heat pumps, were set in 2009. To carry the Energy Star label, a heat pump must achieve at least 14.5 SEER, 12 EER, and 8.2 HSPF.
Models that reach or exceed these efficiencies are approximately 9 percent more efficient than the average new heat pump. They’re around 20 percent more efficient than the older heat pumps still found in many homes today.
If you’re really concerned with energy efficiency, look for systems that have achieved Energy Star Most Efficient status. These models are among the top 5 percent most efficient in their class. To qualify, a heat pump must reach a minimum of 20 SEER, 12.5 EER and 9.6 HSPF. Energy Star Most Efficient requirements change yearly, so you’ll find this status noted in the product’s marketing material, but not on the product itself.
Consortium for Energy Efficiency
Although it doesn’t have as much influence as the EPA, the Consortium for Energy Efficiency (CEE) also works to promote energy efficiency in the heating and cooling industry. The association is made up of electric and gas efficiency program administrators and other professionals from various organizations and agencies around the country.
The CEE doesn’t develop or enforce energy efficiency standards, but they do aim to influence manufacturers, government agencies, and other relevant parties to develop and promote more energy-efficient appliances.
One of the ways the CEE helps homeowners is by maintaining a database called the CEE Directory of Efficient Equipment. In this database, you’ll find equipment that’s been tested to meet standards set by the EPA and the test results verified by the Air-Conditioning, Heating and Refrigeration Institute (AHRI).
Within this database, heat pumps are ranked in one of four efficiency tiers. This makes it easy to search for ductless heat pumps in precisely the efficiency range you prefer. Effective as of January 2015, requirements for split air source heat pumps in each of the four tiers are:
• Tier 0 – SEER 14.5, EER 12, HSPF 8.5
• Tier 1 – SEER 15, EER 12.5, HSPF 8.5
• Tier 2 – SEER 16, EER 13, HSPF 9.0
• Tier 3 – SEER 18, EER 13, HSPF 10.0
Keep in mind that heat pumps in Tier 0 still slightly exceed requirements for Energy Star qualification, so even the least efficient equipment you’ll find in the database is still above-average in efficiency.
If you’re in the market for a new heat pump or any other home comfort equipment, contact us at Griffith Energy Services, Inc. We serve homeowners in and around Baltimore, Hagerstown, and Easton, Maryland, as well as in Dover, Delaware and Martinsburg, West Virginia.
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