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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 water.
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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