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SYSTEM DESCRIPTION
There are three types of heat pumps: air source, ground
source and water source. Ground and water source systems are more commonly
referred to as geothermal systems. Heat pumps work on the principal that heat
exists in the air, soil, and water outside your home.
The heat pump doesn't create heat like conventional heating
systems, it moves heat into your home in the winter (heating cycle), and out of
your home in the summer (cooling cycle). In the spring and fall months with
cool mornings and warm afternoons, the heat pump can automatically switch from
heating to cooling.
The Air Source heat pump is the most common, it
extracts heat from the outside air and brings it into your home. The air source
system is the least expensive of the three.
Ground Source, as the names implies, moves heat from
pipes buried in the earth either horizontally or vertically.
Water Source moves heat from water. The water system
usually operates from a well, but some systems use surface water from a lake or
river. Generally speaking, the water source heat pump is the most efficient
system.
HOW DOES IT WORK?
The Heating Cycle: A liquid refrigerant captures the
heat from the outside air, soil, or water. This heat causes the liquid to warm
and turn into a cool gas. The change from liquid to gas creates large amounts
of energy.
The refrigerant, now a cool gas, is too cool to warm the
house, that's where the compressor comes in. It compresses the gas raising the
temperature drastically. This hot gas moves past the indoor coil, gives up its
heat and in the process, it turns back into a liquid.
A fan blows over the indoor coil and distributes the heat
into your house through a ductwork system. The mixture of warm liquid and gas
continues through the expansion valve, which reduces the pressure, causing the
refrigerant to become a cold liquid ready to start the cycle all over again.
ADVANTAGES
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Generally costs less to operate than all other types of heating
systems.
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Operates at a high-efficiency with no flames, fumes or chimneys.
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Filters are available to remove mold and mildew, which is
helpful for those with allergies.
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Provides a more constant, even temperature, without the swings
common to other heating systems.
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Maintains comfortable temperatures year around.
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Heats and cools the home.
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Transfers heat already in the environment.
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Can provide supplemental wate
DISADVANTAGES
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Larger investment than an electric furnace.
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May cost more to service and repair than other electric heating
systems.
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Some outdoor units may be noisy.
CONTROLS
Heat pumps operate on a single thermostat that
controls both heating and cooling.
EFFICIENCY
Heat pump efficiency is rated in two ways: Heating Season
Performance Factor (HSPF) and Co-Efficient of Performance (COP). In both cases,
the higher the rating, the more efficient the system. Contact Salem Electric
for recommended efficiency ratings.
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HSPF takes into account reductions in efficiency due to
temperature fluctuations, defrosting, fans, supplemental heat and on/off
cycles. Divide the HSPF by 3.4 to determine the average COP.
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COP compares the energy output of a heat pump to
its energy input. A common COP of 2.0 (air source heat pumps) indicates there
is twice as much heat energy being delivered by the heat pump as there is
electric energy used to run it.
MAINTENANCE
Air filters should be cleaned or replaced regularly.
Clear debris from around the outdoor unit to allow proper air flow. Have a heat
pump contractor perform a periodic service of the system.
An annual service agreement is a good idea.
CONTROL TIPS
With manual thermostats, turning the temperature down while
sleeping or when the house is unoccupied is not recommended.
You can turn down the temperature if desired, but when you
increase the temperature, do so in 2-4 degree increments. This prohibits the
back-up heating system from coming on, saving you on operating costs.
If you want to "setback" the thermostat for optimum
effciency, programmable thermostats are available.
EASE OF OPERATION
There's nothing to it... just set the thermostat and walk
away.
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