Q: What is a ductless heat pump?
A ductless heat pump is a highly efficient zonal heating and cooling system that does not require the use of air ducts. Ductless heat pump systems consist of an outdoor compressor unit and one or more indoor air-handling units, called “heads”, linked by a refrigerant line. Indoor heads are typically mounted high on a wall or ceiling covering a 3” hole where the refrigerant line passes through to 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 DHP system can be used as a primary heat source, most homeowners are encouraged to keep their existing heating units to supplement the DHP system in extreme weather (below -20F degree) conditions or in hard to reach extremities of the home.
Q: How does a ductless heat pump work?
Ductless heat pumps are reversible, 2-way heat pumps that use electricity to transfer heat between outdoor and indoor air by compressing and expanding a refrigerant. Using a refrigerant vapor compression cycle, like a common household refrigerator, ductless heat pumps collect heat from outside the house and deliver it inside on the heating cycle, and vise versa on the cooling cycle.Ductless heat pumps use variable speed compressors with “inverter technology” (AC to DC) to continuously match the heating/cooling load, avoiding the on/off cycling of conventional electric resistance and central heating systems that is 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 the space.
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 with a remote control that also functions as a programmable thermostat. Most systems offer various modes of operation such as quiet, high, or timer. Wall mounted controls are also available.
Q: What are appropriate applications for a ductless heat pump?
Replacing an existing zonal heating system – Ductless heat pumps can replace or supplement existing electric baseboard/wall/ceiling units, woodstoves and other space heaters (propane, 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 – Another application for ductless heat pumps is when a room is added to 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 heat pump can provide efficient heating and cooling.
New construction – New homes can be designed or adapted to take advantage of the characteristics of ductless heat pumps. Typically one or more systems might be installed in various “zones” of the house to simplify installation and minimize refrigerant line length.
Q: Are ductless heat pumps efficient?
Yes! Ductless heat pumps can operate using 25% to 50% less energy that electric resistance and forced air systems.
Three key factors account for the high efficiency of ductless heat pumps:
1. Ductless heat pumps 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 heat pumps distributing air directly into each zone, resulting in 25% greater efficiency.
2. Ductless heat pumps 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.
3. Modern ductless heat pumps have ultra-high Seasonal Energy Efficiency Ratios Cooling (SEER) between 16 and 33, and Heating Seasonal Performance Factors (HSPF) between 8.5 and 15.
Q: How long have ductless heat pumps been around?
Ductless heat pumps were developed in Japan in the 1970’s and have since become a preferred heating and cooling system in Asia and much of Europe. In the United States ductless heat pumps have been used in commercial applications for over 20 years.
Q: How much does a ductless heat pump cost?
The average cost of an installed ductless heat pump with one 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: the manufacturer and model, refrigerant line-set length, difficulty of installation, and contractor rates.
Q: What incentives are available for ductless heat pumps?
Utility Rebate - A number of public utilities in the Northeast are offering their customers cash rebates as high as $2,500+ when they install a ductless heat pump. Check with your local utility for details.
Q: How long will a ductless heat pump system last?
With proper maintenance and care a ductless heat pump should perform for over 20 years. Many systems installed in the 1980’s are still functioning well today.
Q: What kind of maintenance does a ductless heat pump require?
Ductless heat pumps require some basic maintenance to ensure optimum performance. In most cases keeping the filters and coils clean is all the maintenance needed, and can be performed easily by the home owner.
Q: How do I know what size of system my house needs?
Ductless heat pump systems are sized to meet the heating and cooling needs of individual zones in the home. There is a great deal of flexibility when it comes to system sizing as one indoor unit can provide between 1/2 and 5 tons of heating/cooling depending on its BTU capacity rating. Some common capacities for indoor units are 7k, 9k, 12k, 15k, 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 or may not be necessary for multi-zone systems.