Heat Pumps

A heat pump can be used to provide heating and cooling to a space, making them an extremely efficient option and a great alternative to having both a furnace and an air conditioner. There are many different types of heat pumps use either electricity or gas. Let R&B plumbing install a heat pump application that is right for you.

How does a heat pump work? A heat pump uses electricity to move heat from a cool space into a warm space, making the cool space cooler and the warm space warmer. During the winter, a heat pump moves the heat from the cold outdoors into your warm house while during the summer, a heat pump moves heat from your cool house into the warm outdoors.

Why are they so efficient? When properly installed, an air-source heat pump can deliver one-and-a-half to three times more heat energy to a home than the electrical energy it consumes. This is possible because a heat pump moves heat rather than converting it from a fuel, like in combustion heating systems.

The most common type is the air-source heat pump, which transfers heat between your house and the outside air. If you heat with electricity, a heat pump can reduce the amount of electricity you use for heating by as much as 30%–40%.  High-efficiency heat pumps also dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months. The efficiency of most air-source heat pumps as a heat source drops dramatically at low temperatures, generally making them unsuitable for very cold climates. However, new systems with gas heating as a backup are available to overcome this problem.

For homes without ducts, air-source heat pumps are also available in a ductless version called a mini-split heat pump. Ductless, mini-split-system heat pumps make good retrofit add-ons to houses with "non-ducted" heating systems, such as hydronic (hot water heat), radiant panels, and space heaters (wood, kerosene, propane). They can also be a good choice for room additions, where extending or installing distribution ductwork is not feasible.

Like standard air-source heat pumps, mini splits have two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units.

The main advantages of mini splits are their small size and flexibility for zoning or heating and cooling individual rooms. Many models can have as many as four indoor air handling units (for four zones or rooms) connected to one outdoor unit. The number depends on how much heating or cooling is required for the building or each zone (which in turn is affected by how well the building is insulated). Since each of the zones will have its own thermostat, you only need to condition that place when someone is there, saving energy and money.

Ductless mini-split systems are also often easier to install than other types of space conditioning systems. For example, the hook-up between the outdoor and indoor units generally requires only a three-inch hole through a wall for the conduit. Also, most manufacturers of this type of system can provide a variety of lengths of connecting conduits. If necessary, you can locate the outdoor unit as far away as 50 feet from the indoor evaporator. This makes it possible to cool rooms on the front side of a building house with the compressor in a more advantageous or inconspicuous place on the outside of the building.

Since mini splits have no ducts, they avoid the energy losses associated with ductwork of central forced air systems. Duct losses can account for more than 30% of energy consumption for space conditioning, especially if the ducts are in an unconditioned space such as an attic.

In comparison to other add-on systems, mini splits offer more flexibility in interior design options. The indoor air handlers can be suspended from a ceiling, mounted flush into a drop ceiling, or hung on a wall. Floor-standing models are also available. Most indoor units have profiles of about seven inches deep and usually come with sleek, high tech-looking jackets. Many also offer a remote control to make it easier to turn the system on and off when it's positioned high on a wall or suspended from a ceiling.

Split-systems can also help to keep your home safer since there is only a small hole in the wall. Through-the-wall and window mounted room air-conditioners can provide an easy entrance for intruders.

The primary disadvantage of mini splits is their cost, approximately 30% more than central cooling systems (not including ductwork) and may cost twice as much as window units of similar capacity.

The installer must also correctly size each indoor unit and judge the best location for its installation. Oversized or incorrectly located air-handlers often result in short-cycling, which wastes energy and does not provide proper temperature or humidity control. Too large a system is also more expensive to buy and operate.

Some people may not like the appearance of the indoor part of the system. While less obtrusive than a window room air conditioner, they seldom have the built-in look of a central system. There must also be a place to drain condensate water near the outdoor unit (http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12610)

For a more detailed look at heating and cooling with a heat pump, please download the document, Heating and CoolingWith a Heat Pump, produced by Natural Resources Canada’s Office of Energy Efficiency EnerGuide which can be found here http://oee.nrcan.gc.ca/publications/infosource/pub/home/heating-heat-pump/booklet.pdf

At R&B we offer the following brands of heat pumps but can repair and replace parts on all types:

Carrier http://www.residential.carrier.com/products/acheatpumps/heatpumps/index.shtml

Whirlpool http://www.whirlpoolhvac.com/products/heat_pumps

• What does the efficiency rating meand and how can it be compared to the AFUE ratings of the gas heating systems?

• How much energy will it use in the summer to cool the house?

• How does a heat pump work?

  A heat pump is a device used for transferring heat from a substance or space at one temperature to another at a higher temperature. It consists of a compressor, a condenser, a throttle or expansion valve, an evaporator, and a working fluid (refrigerant). The compressor delivers vapourized refrigerant to the condenser in the space to be heated. There, cooler air condenses the refrigerant and becomes heated during the process. The liquid refrigerant then enters the throttle valve and expands, coming out as a liquid-vapour mixture at a lower temperature and pressure. It then enters the evaporator, where the liquid is evaporated by contact with the warmer space. The vapour then passes to the compressor and the cycle is repeated. A heat pump is a reversible system and is commonly used both to heat and to cool buildings. It operates on the same thermodynamic principles as refrigeration. 

• How is a heat pump installed and how long does it take?

• Should I cover my outdoor unit in the winter?

• How much noise does it make?

• What is the difference between an air source and a ground source (geothermal) heat pump?

  Geothermal (or ground source) heat pumps (GHPs) use the constant temperature of the earth as the exchange medium instead of the outside air temperature as is used in an air source heat pump. This allows the system to reach fairly high efficiencies (300%-600%) on the coldest of winter nights, compared to 175%-250% for air-source heat pumps on cool days. 

  Ground source and air-source heat pumps are both highly efficient and environment friendly systems. An air source heat pump is less expensive to install than a ground-source system, because it requires less materials. While ground source utilize pipes embedded several feet underground that involves more labor and equipment. However, ground-source heat pumps are much cheaper to operate. The systems both have their pros and cons that needed to be considered.