More about... Heat Pumps
Heat pumps offer the most energy efficient way to provide heating and cooling in many
applications, as they can use renewable heat sources in our surroundings. Even at
temperatures we consider to be cold, air, ground and water contain useful heat that's
continuously replenished by the sun. By applying a little more energy, a heat pump can
raise the temperature of this heat energy to the level needed. Similarly, heat pumps can
also use waste heat sources such as from industrial processes, cooling equipment or
ventilation air extracted from buildings. A typical electrical heat pump will just need
100 kWh of power to turn 200 kWh of freely available environmental or waste heat into 300
kWh of useful heat.
Because heat pumps consume less primary energy than conventional heating systems, they
are an important technology for reducing emissions of gases that harm the environment,
such as carbon dioxide (CO2), sulfur dioxide (SO2) and nitrogen oxides (NOx). However, the
overall environmental impact of electric heat pumps depends very much on how the
electricity is produced. Heat pumps driven by electricity from, for instance, hydropower
or renewable energy reduce emissions more significantly than if the electricity is
generated by coal, oil or gas fired power plants.
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Heat Pump Facts:
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Using direct combustion, (gas or oil) to generate heat is never the most efficient use
of fuel.
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Heat pumps are more efficient because they use renewable energy in the form of
low-temperature heat.
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Heat Pump Operation:
Heat flows naturally from a higher to a lower temperature. Heat pumps, however, are
able to force the heat flow in the other direction, using a relatively small amount of
high quality drive energy (electricity, fuel, or high temperature waste heat). Thus heat
pumps can transfer heat from natural heat sources in the surroundings, such as the air,
ground or water, or man-made heat sources such as industrial or domestic waste, to a
building or an industrial application. Heat pumps can also be used for cooling. Heat is
then transferred in the opposite direction, from the application that is cooled, to
surroundings at a higher temperature. Sometimes the excess heat from cooling is used for
to meet a simultaneous heat demand.
In order to transport heat from a heat source to a heat sink, external energy to drive
the heat pump is needed. Theoretically, the total heat delivered by the heat pump is equal
to the heat extracted from the heat source, plus the amount of drive energy supplied.
Electrically driven heat pumps for heating of buildings typically supply 100 kWh of heat
with just 20-40 kWh of electricity. Many industrial heat pumps can achieve even higher
performance, and supply the same amount of heat with only 3-10 kWh of electricity.
Simply put, during a call for cooling, a heat pump will remove heat and humidity from
your home and will transfer this heat to the outdoor air.
During the heating cycle, a heat pump will remove heat and humidity from the outdoor
air and will transfer this heat to your home. This is possible because even 0 degrees
Fahrenheit outdoor air contains a great deal of heat. Remember that your heat pump doesn't
generate much heat it merely transfers it from one place to another.
Heat Pump Characteristics: A Constant Heat:
A heat pump delivers a lower supply air temperature than a furnace over a longer period
of time to provide a more constant heat. It may give you the impression that your system
"never stops running", or "it feels like cold air". At times, the
temperature of the air coming out of the vents is less than your body temperature so it
feels like cold air. But it is still providing heat for your house. And when it can no
longer keep-up with the heat loss of the structure, the 2nd stage or auxiliary heat will
automatically energize, bringing on a much warmer heat.
Water Run-Off:
During the heating cycle, you may notice water running off the outdoor coil. Moisture
from the air is condensed on the outside surface of the coil where it gathers and runs
off. This is normal.
Outdoor Coil Defrosting:
At certain conditions (low temperature, high humidity), frost, even ice, may build up
on the coil of the outdoor unit. In order to maintain heating efficiency, the system will
automatically defrost itself. Steam rising form the outdoor unit is normal and is and
indication of proper operation. The vapor cloud will only last for a few minutes. When the
defrost cycle is completed, the system will automatically switch back to heating.
Supplemental heat is automatically energized to maintain comfort during defrost.
Heat Pump Tips:
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Set thermostat at one temperature. Constant adjusting can cause higher utility costs.
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If using your thermostat as a setback type, limit the setbacks to twice a day such as
when you are at work and when you are sleeping.
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Only setback the thermostat 6% of desired temperature( approximately five degrees).
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In heating, try not to set the thermostat below 65 degrees.
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In cooling, try not to set the thermostat below 70 degrees. Besides higher utility
costs, this can cause the indoor coil to freeze and cause condensation in the house.
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Make it a habit to look at the outdoor heat pump during the winter months for signs of
excessive ice or snow build-up on or around the heat pump. Especially after bad weather.
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If the unit is covered in ice or snow it must be removed for it to work properly. Turn
the thermostat to Emergency heat or off and remove the snow and ice. You can pour warm or
hot water over the unit to melt the snow and ice. Even cold water from a hose will help.
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Do not use any sharp objects to pick or knock the ice off the coils of the heat
pump. This could cause severe damage and personal injury.
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Once the unit is clear of snow and ice turn the thermostat back to normal heating. If
the unit ices up again, call for service.
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Do not let the outdoor unit sit underneath a leaking gutter. In the winter months, water
will drip on the top of the unit and freeze solid. This will restrict the air flow and
cause the whole unit to freeze-up.
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Heat Pumps should be elevated 4 to 8 inches above ground level to keep coils clear of
snow and ice and to allow for proper drainage. Contact our Service Department if you would
like your unit raised.
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Heat Pump Maintenance:
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Check air filters monthly. Clean or replace as needed.
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Keep outdoor unit clear of snow, ice, and debris. This includes the top, sides, bottom,
and around the heat pump.
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Keep coils clean. If they get dirty you can use a heavy duty degreaser and hose them
down. Just turn the unit off first.
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Keep shrubs pruned back at least 18 inches around all sides of the heat pump.
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Flush the indoor condensate drain in spring before using the air conditioning. This is
extremely important if the unit is above or in a finished living area.
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Some fan motors need to be oiled annually.
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Last but not least, we suggest having your heat pump inspected by a service technician
at least once a year. |
HVAC Maintenance Tips
The Fall is a time to make sure your home is in shape for the upcoming winter.
When was the last time your HVAC (Heating Ventilating Air Conditioning) system was
serviced? Whether you have baseboard heater, heat pump, closed
loop or forced air, now is the time to insure that the upcoming winter months will be warm
and cozy. If your system has been checked in the last 24 months, be sure that your filters
are clean and replace them if needed. Clean the dust off the heating fins of your
baseboard to avoid that “hot smell” when first brought to temperature.
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HVAC System Replacement & Fall Service
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Find a local reputable company!
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Investigate the brands they sell. The local library rates companies and brands. How do
they rate? Serviceability? Cost?
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Find out if there is a local distributor close by, who stocks the equipment and parts
for the brand you choose.
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Have a salesperson or technician visit your home to determine
the size and type of system you need. Questions To Ask The Salesperson:
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Does the system have adequate blower capacity? Most homes were undersized in the airflow
dept.
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What efficiency do you recommend? 80% or 90% plus? Why?
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Do I have an up flow or counter flow design?
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Will the furnace have an electronic ignition?
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How long is the warranty on the heat exchanger and compressor? Parts & Labor?
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Do they offer a service contract?
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Compare costs. Always get more than one estimate!
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Make sure the installing contractor takes the time to go over the installation with you
especially if you are purchasing a programmable thermostat with your system. Have them
show you how to change filters, operate and service the humidifier, the electronic air
cleaner, etc.
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Always have your system checked at least twice a year, to ensure optimum performance,
cost efficiency and for your health as well as your family's!
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