Air-Source Heat Pumps
 The
air-source heat pump is a combination heating and cooling system which when
used with an electric or gas furnace will provide optimum value for your
energy dollar. This combination uses the high efficiency of the heat pump
during the milder part of the winter, automatically switching to the
electric or gas furnace during the coldest part of the winter. This heating
system uses the best of both types of systems to provide a more efficient
source of heat. This in turn will lower the overall heating costs.
During the summer, the air-source heat pump works
as a high efficiency air conditioner to maintain indoor comfort.
Here's How It Works
The heat pump is able to capture heat energy from
the outdoor air to warm your home. During the milder part of the winter, the
heat pump transfers heat more efficiently than a gas or electric furnace can
produce it. This increased efficiency will reduce your heating cost.
During the winter there is always some heat in
the air. The heat pump uses the refrigeration process to transfer heat from
the outdoor air, releasing it inside your home. This heat transfer is
accomplished by a compressor circulating a refrigerant from the outdoor
section to the indoor furnace section, working much like your refrigerator.
 Oversimplified,
a heat pump is much like a reverse air conditioner. If you have felt the
heat on the outside of a window air conditioner, picture that air
conditioner being turned around. The heat you felt would now be heating the
house. Working much like this reversed air conditioner, the heat pump uses
this refrigeration principle to provide heat for the home.
In the summer the heat pump works just like a
central air conditioner. In fact from all outward appearances, the heat pump
works exactly like a central air conditioner. When working in the cooling
mode, the heat pump removes heat from the inside and transfers it outside,
thereby cooling your home exactly like a central air conditioner.
The air-source heat pump gives you from 2 to 3
units of heat for each unit of energy used. This high efficiency, combined
with CMEC's rate of 4.7 cents per kilowatt hour, means an air-source heat
pump is more economical to operate than an electric or gas furnace alone.
Heat Pump With Electric Backup
It has already been pointed out that air-source heat
pumps require a backup system for assistance during the colder periods of
the heating season. One viable option to consider would be an electric
source of heating. This could include electric strips in the blower cabinet
of the heat pump, electric baseboard, electric radiant, ceiling cable(in
existing applications), and others. With this application, the heat pump
will always be the first source of heat when the thermostat calls for heat.
Typically, 80% of the heat requirements during a heating season will be
filled by the heat pump. However, there are times when the outdoor
temperatures will not allow the heat pump to keep up with the building's
requirements. At this point, the thermostat will sense the heat pump is not
keeping up and call for the backup source of heat. The heat pump will
continue to produce heat and the backup source will simply add to that heat
until the thermostat is satisfied. All equipment used for heating and
cooling(HVAC) qualifies for CMEC's 4.7 cent per kilowatthour rate.
Heat Pump With Gas Backup
 If
you have an existing gas furnace and would like to lower your heating and
cooling costs, consider adding an air-source heat pump. The system works
very similar to the all-electric system with one exception. The heat pump
will operate down to a preselected outdoor temperature called a switchover
point. Once the outdoor temperature reaches this point, the gas furnace will
provide the heat. This switchover point should be determined on a case by
case basis depending on the cost of gas(propane, natural gas, or oil), the
energy efficiency of the building being heated, and the comfort level
required by the occupants. The efficiency of this type of system is also
improved because of the heat pump. Typically, 75% of the heating
requirements will be filled by the heat pump. The electric usage of the
outdoor unit is the only equipment allowed to be on CMEC's 4.7 cent per kilowatthour rate.
If you are considering a new house or upgrading the
heating and cooling system in an existing building, consider a heat pump.
CMEC offers cash rebates for the installation of heat pumps to help with
your decision. The Marketing and Member Services Department at CMEC will be
glad to answer any of your questions concerning air-source heat pumps so
contact them today. |
