Vermont Heat Pump F.A.Q.

Yes, in general people use the term ductless heat pump, and mini split heat pump interchangeably in Vermont and throughout the northeast United States.

A ductless heat pump is a highly efficient zoned refrigerant based heating and cooling system that does not require a central duct system. A ductless heat pump has an outdoor unit and one or more indoor units with a refrigerant lineset and wiring harness connection between them. The indoor units are most commonly very compact and are mounted 6 - 8' above the floor of an indoor space, and deliver heated or cooled air directly to the conditioned space in which it is located.

Ductless heat pumps are a refrigerant based HVAC solution. They utilize electricity and a compressor based system to move thermal energy from outdoor air into you home in the winter, and extract heat from indoor air and expel it outdoors in the summer. All modern ductless heat pumps utilize variable speed technology which makes them more efficient and more comfortable to live with.

Outdoor unit:

• Inverter Compressor: Traditional HVAC compressors are on or off. The compressor is off or its running at 100 percent. Inverter compressor always running in the background, adjusting the compressor speed in real time. By ramping up and down as needed an inverter provides a more accurate, on-demand approach to temperature control. The variable speed DC current drive operates much more efficiently than a traditional AC compressor.
• Condensing fan motor: Fan motors move air across the outdoor coil to facilitate thermal transfer. Mini split heat pumps utilize efficient variable speed fan motors that improve performance through a wide ambient operating temperature range.
• Reversing valve: A ductless heat pump reverses its refrigerant flow from summer to winter. Modern reversing systems and smooth and reliable.
• System defrost: During heating mode a defrost system may be initiated when the outdoor coil temperature falls below 32°F and the moisture in the air starts to freeze on the outdoor unit’s heat exchanger. Sensors in the outdoor unit detect that frost or ice has started forming. The indoor and outdoor fans will stop, and the compressor keeps running to melt accumlated ice.

Indoor Units: Each indoor unit comprises an HVAC zone that can be controlled independently.

• With our primary line Mitsubishi, there can be from one to eight indoor units for a given outdoor unit. Traditional ductless indoor units unit are high wall, typically between 7.0 and 36.0 MBtuH, and are mounted about seven from from floor level. Other indoor units can be floor mounted, ceiling mounted, or are air handlers designed to be used with very short duct systems.
• Indoor fan motors: Mini splits have ultra quiet DC drive variable speed motors for air flow flexibility and comfort.
• Indoor controls: Traditionally ductless systems include a hand-held remote to control the operation of the indoor unit. There is also the option of wall mounted controls similar to traditional thermostats, or App based control via an Apple or Android mobile devices.

Lineset(s): Between the outdoor and indoor unit(s), a lineset is installed that contains two insulated copper tubes, along with a power / communication cable, and a condensation drain. This lineset is very compact and only requires a 3" diameter accessway.

Modern ductless heat pumps were first developed in the far east starting in the late 1950's. From that time through the turn of the century, they became widely used throughout the Asia, and then in Europe. The first installations in New England occurred in the 1990's, and as a result of their excellent low temperature winter performance, they became increasingly popular here in Vermont starting about 20 years ago.

Mitsubishi Hyperheat H2I® model heat pumps provide full system capacity to 5°F, and efficient operation to -13°F. Here in Vermont, Mitsubishi heat pumps are a perfect choice for year around comfort and efficiency. However, based on the heat loads of your building, you may need supplemental heating on the coldest nights of the year to maintain consistent indoor comfort. However it's important to note that in Vermonts Champlain Valley, an average much less than 1% of our heating load each year occurs when outdoor temperatures are below 0°F.

Energy Star rated ductless heat pumps typically utilize 60% less energy than electric resistance heating, and are considerably less expensive to operate than conventional oil or propane boilers or furnace. In addition, because ductless systems do not require ductwork, according to the US Department of Energy, they will consumer 30% less energy than ducted HVAC systems.

With proper installation, and consistent maintenance, you heat pump system should last for 20 years or more.

Like all modern HVAC systems, ductless heat pumps must be properly sized for your specific application. The most common cause of consumer dissatisfaction and inefficiency is improve sizing. A professional heat loss gain should be performed by a trained professional prior to a purchase decision being made.

Most indoor units include washable reusable filters. Every month or two they should be inspected and cleaned as necessary but this is a simple and quick process. At Vermont Energy, we also recommend annual system clean and checks. We will clean both the indoor and outdoor units thoroughly and ensure proper system operating.

• Energy savings in both heating and cooling: with SEER ratings as high as 33.0, and heating HSPF to 12.5, ductless systems are much less expensive to operate than electric, oil, or LP gas systems. They are also the most efficient cooling system available in most applications.
• Flexibility: With a broad range of sizes and configurations, you application can be configured to exactly meet your needs.
• Space saving: There is no indoor mechanical space require for ductless systems, so that space typically devoted to a furnace or boiler, and ductwork, is not necessary.
• Easy to install: ductless systems can be installed quickly. They do not require ductwork, and our 3" linesets can be typically run with a minimum amount of disruption.
• System zoning: With ductless, zoning is simple. You can have accurate temperature control in you application for any zone you set-up.

IDS stands for "Inverter Ducted Split." This is a relatively new platform from technology lead Bosch Thermotechnology. It is designed for efficient heat pump performance when you're replacing a ducted system, or when you want the benefits of a centrally ducted HVAC system.

Yes, it offers a SEER rating of up to 20.5 and an HSPF of up to 10.5. More importantly, it is designed for cold weather heating performance. If can effectively heat to outdoor temperatures of -4°F or below.

Yes. There are incentives of up to $2000 for the installation of a Bosch IDS premium system.

Every application is different and there are certainly applications, like a furnace replacement, where a Bosch IDSA system is the clear choice. The Bosch IDS system utilizes a ducted system, and it's critical that your ductwork is properly sized, sealed, and insulated. Vermont Energy offers free detail site evaluations and we can help you decide what heat pump system is best for your application.

A great choice for Vermont homeowners is a Bosch IDS system combined with a variable speed drive natural gas or LP gas furnace. When winter temperatures fall and your building's heat load is higher than the output capacity of you IDS inverter, you gas furnace can cycle in to add more system capacity. It is important to understand that even here in Vermont, we spend less than 1% of the heat season with temperatures below 0°F so a Bosch IDS dual fuel system is still a great green choice.