Ductless Heat Pumps – Questions…Answered.
Q: What is a ductless heating and cooling system?
A ductless heating and cooling system is a highly efficient zonal heating and cooling system that does not require the use of air ducts. Ductless systems consist of an outdoor compressor unit and one or more indoor air-handling units, called “heads”, linked by a dedicated refrigerant line. Indoor heads are typically mounted high on a wall or ceiling covering a 3” hole where the refrigerant line passes through from the outside unit, which is mounted at the base of the house. Each indoor head corresponds with a heating and cooling zone that can be controlled independently.
Q: Do I still need my old heaters?
While a ductless system can be used as a primary heat source, homeowners are encouraged to keep their existing electric heating units as a supplement the Ductless system in case of extreme weather conditions or in hard to reach extremities of the home.
Q: How does a ductless system work?
Ductless systems are reversible, 2-way heat pumps that use electricity to transfer heat between outdoor and indoor air by compressing and expanding refrigerant. Using a refrigerant vapor compression cycle, like a common household refrigerator, ductless systems collect heat from outside the house and deliver it inside on the heating cycle, and vice versa on the cooling cycle. Ductless systems use variable speed compressors with “inverter technology” (AC to DC) in order to continuously match the heating/cooling load, avoiding the on/off cycling of conventional electric resistance and central heating systems that is commonly associated with uncomfortable temperature variations and high energy consumption.
Ductless Systems consist of several parts:
- An outdoor unit that contains a condensing coil, an inverter-driven variable speed compressor, an expansion valve and a fan to cool the condenser coil.
- An indoor unit that contains an evaporator and a quiet oscillating fan to distribute air into throughout the heating zone.
- A refrigerant line-set that is made of insulated copper tubing and is housed in a conduit alongside a power cable, and a condensation drain.
- A remote control that can be used to set the desired temperature and program in night-time settings.
Q: How is the system controlled?
The system is controlled via remote control that changes temperature as well as mode of operation. Wall mounted controls are also available.
Q: What are appropriate applications for a ductless system?
- Replacing an existing zonal heating system – Ductless systems are ideal for replacing or supplementing inefficient electric baseboard, wall or ceiling units, woodstoves and other space heaters such as propane or kerosene. A cost effective electric heat conversion in a small house might consist of single system serving the main area of the house, while leaving existing electric baseboards in bedrooms and bathrooms.
- Room additions – A ductless system can also be implemented when a room is added onto a house or an attic is converted to living space. Rather than extending the home’s existing ductwork or pipes, or adding electric resistance heaters, the ductless sytem can provide efficient heating and cooling.
- New construction – New home designs can be adapted to take advantage of a ductless system’s many benefits. One or more systems might be installed in various “zones” of the house to simplify installation and minimize refrigerant line length.
Q: Are ductless systems efficient?
Yes! Ductless systems operate using 50% to 75% less energy than electric resistance and forced air systems. Three key factors account for the high efficiency of a ductless system:
- Ductless systems allow the user to control each heating/cooling zone independently, eliminating the costly over-heating and cooling common to central air systems. Why pay to heat or cool rooms that are not currently occupied?
- While central air systems lose as much as 30% efficiency through air leaks and conduction in the ductwork, ductless systems distribute air directly to each zone, resulting in 25% greater efficiency. Ductless systems use inverter-driven, variable speed compressors that allow the system to maintain constant indoor temperatures by running continuously at higher or lower speeds. Thus, the system can ramp-up or down without great losses in operating efficiency, avoiding the energy intensive on/off cycling common in electric resistance and forced air systems.
- Modern ductless systems have ultra-high Seasonal Energy Efficiency Ratios (SEER) between 16 and 22, and Heating Seasonal Performance Factors (HSPF) between 8.5 and 12.
Q: How long have ductless systems been around?
Ductless heating and cooling systems were developed in Japan in the 1970’s and have since become a preferred heating and cooling system throughout Asia and much of Europe. In the United States ductless systems have been used in commercial applications for over 20 years.
Q: How much does a ductless system cost?
The average cost of an installed ductless systems with a single indoor heating/cooling zone is between $3,000 and $5,000. Additional heating zones and greater heating capacities will increase the cost of the system. Other factors that will affect the cost of an installed system include manufacturer and model, refrigerant line-set length, difficulty of installation, and contractor rates.
Q: What incentives are available for ductless systems?
- Utility Rebates: most utilities in the Northwest are offering their customers cash rebates as high as $1,500 when they upgrade their existing electric resistance heating system to a ductless system. Interest-free financing may also be available. Check with your local utility for details.
- Federal Tax Credits – Additional Incentives: Federal Tax Credits: tax credits for Consumer Energy Efficiency may be available to taxpayers who purchase a qualified energy-efficient residential ductless systems.
Q: How long will a ductless system last?
With proper maintenance and care a ductless systems should perform for over 20 years. Many of the systems installed during the 1980’s are still functioning well today.
Q: What kind of maintenance does a ductless system require?
Ductless systems require basic maintenance to ensure optimum performance. In most cases maintenance is limited to keeping filters and coils clean. These tasks can easily be performed by the home owner.
Q: How do I know what sized system my house needs?
Ductless systems are sized to meet the heating and cooling needs of a home’s individual zones. There is a great deal of flexibility when it comes to system sizing as one indoor unit can provide between ¾ and 2 ½ tons of heating/cooling depending on its BTU capacity rating. Some common capacities for indoor units are 9k, 12k, 18k, 24k, and 30k BTU. Outdoor units are sized to meet the combined load of all heating/cooling zones. More than one outdoor unit may be necessary for multi-zone systems.
Posted by Wes Diskin