All About Cold-Climate Ductless Heat Pumps
Aug 06, 2019
Ductless heat pumps have come a long way in the last decade. While single-speed and even two-stage heat pumps struggle at the coldest temperatures, demand for the technology has grown in colder regions of North America and Scandinavia and the technology has matured to serve these climates.
Today, every major manufacturer (along with some of the smaller ones, too) offers extended capacity, or “cold climate,” ductless heat pumps. In fact, cold-climate ductless systems are capable of providing at least 80–85% of their heating capacity at temperatures as cold as 5 °F, making them the new go-to technology for many HVAC contractors who work in colder areas.
The recommendations for cold climate ductless heat pumps include:
- Cold Climate DHP Specification and Recommendations
- Best Practices for Installing Ductless Heating and Cooling Systems
- Design Evolution for HVAC Systems
If you service an area where temperatures frequently dip below freezing and have electric resistance heat, then a cold-climate ductless heat pump is an efficient and high performing solution that you can offer.
What is considered "cold climate"?
“Cold climate” is a general term used to describe DOE Climate Zones 5 and higher, or any location that experiences extended periods of below-freezing temperatures. In the Northwest, this generally means east of the Cascade mountains, but homes west of the Cascades should be treated as “cold climate” if they’re above 2,500 feet elevation or if temperatures regularly fall below 5 °F.
What is a cold-climate ductless heat pump?
A cold-climate, or extended capacity, ductless heat pump is an inverter-driven ductless mini-split pump that can provide effective heating for a home when outdoor temperatures are as low as -15 °F or cooling when exterior temperatures are above 105 °F.
To meet the Northwest Specifications, cold-climate ductless heat pumps must meet these minimum specifications:
- Must have a variable capacity, inverter driven compressor, in order to out-perform single stage compressor systems, and deliver:
- Better air distribution, thanks to longer run times
- Better temperature and humidity control at extreme temperatures
- Better air quality
- Quieter operation
- Greater efficiency
- Indoor and outdoor units must be part of an AHRI match system, which matches indoor and outdoor units to verify that they will work together as a system to achieve the energy efficiency and longevity homeowners expect
- Heating Seasonal Performance Factor (HSPF) greater than or equal to 10.0.
- Maintain 80% of its rated capacity at 5 °F without the aid of electric resistance backup heating
- The Coefficient of Performance (COP) at 5 °F is greater than 1.75 at maximum capacity. This will indicate the heat pump’s ability to efficiently deliver heat when the system needs it (without the aid of electric resistance backup heat)
- Must have a drain pan heater (or equivalent) controlled by the DHP to run only as part of the defrost cycle
When should a cold-climate ductless heat pump be used?
Cold-climate ductless heat pumps are an excellent choice for displacing a home’s existing electric resistance heating system, like baseboards or wall heaters, by meeting the heat load most of the time, but allowing the existing electric resistance heat to supplement in the most extreme temperatures. Less expensive non-cold climate ductless heat pumps won’t work as well when temperatures dip below freezing, which can significantly impact energy efficiency and homeowner savings and comfort.
How should you size the system?
Proper system sizing will keep the initial purchase price low, maximize system performance and allow for greater efficiency. You should make sure the cold-climate ductless heat pump has both capacity to sufficiently heat a home during peak winter months, as well as the ability to maintain temperatures in the home under mild weather conditions without sacrificing performance. Before upgrading an HVAC system, be sure to discuss with the homeowners the benefits of weatherizing the home (installing insulation and reduce air leaks) — consider starting with a weatherization professional who can assess the home for potential upgrades. The more efficient the overall home’s envelope, the less power will be needed (size and capacity) for the cold-climate ductless heat pump.
For more information on proper sizing, please reference our Cold Climate Ductless Heat Pump Recommendations Guide.
Does my preferred brand make a cold-climate ductless heat pump?
Start by reviewing this database of qualified products from major brands that meet cold-climate ductless heat pump standards, which is maintained by the Northeast Energy Efficiency Partnership (NEEP). For more technical application-specific product recommendations, reference the “Model Selection” section of the Cold Climate Ductless Heat Pump Recommendations Guide.
Is any special maintenance required?
All mini-splits need regular maintenance. Follow these simple guidelines to maintain performance and extend the life of the system:
- Avoiding using condensate pumps whenever possible — they’re noisy, and the filters require regular cleaning
- Ensure proper covers are used on all outside piping to protect the line set from damage
- Recommend annual cleaning service calls to your customers and include inspection and cleaning of the condensate lines to check for any debris and blockages
- Suggest that homeowners clean the filters on the indoor head/cassette every 3–4 months and follow the directions on this Homeowner’s Guide.
How can homeowners maximize efficiency?
Operating a ductless system can have a big impact on its efficiency and performance. Along with the tips listed below, be sure to go over the owner’s manual with the homeowner to ensure they understand how to operate their new system.
- Keep snow and debris away from the outdoor unit
- Use the “heat” or “cool” setting rather than the “auto” setting — using the “auto” setting can greatly increase energy use and cause the ductless heat pump to interact poorly with other heating systems
- Set the fan speed to “automatic” — this allows the fan to operate as quietly as possible
- Avoid setting a nighttime temperature setback more than 4 °F from the daytime temperature setting — ductless heat pumps provide best efficiency and comfort with a steady temperature setpoint and small night setback
- Assist the homeowner in setting their backup heating thermostat to 3–4 degrees lower than the ductless heat pump thermostat — this will ensure the ductless system provides the majority of heating, and the backup heat is only used to supplement during extreme cold temperatures
- Only turn off the system when neither heating nor cooling is needed for an extended period of time (primarily during shoulder seasons or when on extended vacation away from the home)
Are utility rebates available?
Many utilities throughout the Pacific Northwest offer rebates on the purchase of a ductless heat pump — some up to $1,500 for qualified customers. To see if your homeowner is eligible for rebates, visit the Utility Rebates page and enter their ZIP Code to find the local electric utility.
Even if you routinely service an area where temperatures frequently dip below freezing, a ductless system can still be a good sales avenue for your company — as long as it’s properly sized and maintained. Visit GoingDuctless.com to learn more.