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Home >> Articles >> Electric Heaters
What is Electric Heat?
Electric Heat - A heating system in which the energy source is
electricity and the heat is produced by resistance elements.
Electric resistance heating converts nearly 100% of the energy
in the electricity to heat. However, most electricity is
produced from oil, gas, or coal generators that convert only
about 30% of the fuel's energy into electricity. Because of
electricity generation and transmission losses, electric heat is
often more expensive than heat produced in the home or business
using combustion appliances, such as natural gas, propane, and
oil furnaces.
If electricity is the only choice, heat pumps are preferable in
most climates, as they easily cut electricity use by 50% when
compared with electric resistance heating. The exception is in
dry climates with either hot or mixed (hot and cold)
temperatures (these climates are found in the non-coastal part
of California; the southern tip of Nevada; the southwest corner
of Utah; southern and western Arizona; southern and eastern New
Mexico; the southeast corner of Colorado; and western Texas).
For these dry climates, there are so few heating days that the
high cost of heating is not economically significant.
We have a large selection of
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Electric resistance heating may also make sense for a home
addition if it is not practical to extend the existing heating
system to supply heat to the new addition.
Types of Electric Resistance Heaters
Electric resistance heat can be supplied by centralized
forced-air electric furnaces or by heaters in each room. Room
heaters can consist of electric baseboard heaters, electric wall
heaters, electric radiant heat, or electric space heaters. To
learn about electric radiant heat and electric space heaters,
see the radiant heating and small space heaters sections. It is
also possible to use electric thermal storage systems to avoid
heating during times of peak power demand.
Electric Furnaces
Electric furnaces are more expensive to operate than other
electric resistance systems because of their duct heat losses
and the extra energy required to distribute the heated air
throughout your home. Heated air is delivered throughout the
home through supply ducts and returned to the furnace through
return ducts. If these ducts run through unheated areas, they
lose some of their heat through air leakage as well as heat
radiation and convection from the duct's surface.
Blowers (large fans) in electric furnaces move air over a group
of three to seven electric resistance coils, called elements,
each of which are typically rated at five kilowatts. The
furnace's heating elements activate in stages to avoid
overloading the home's electrical system. A built-in thermostat
called a limit controller prevents overheating. This limit
controller may shut the furnace off if the blower fails or if a
dirty filter is blocking the airflow.
As with any furnace, it's important to clean or replace the
furnace filters as recommended by the manufacturer, in order to
keep the system operating at its top efficiency.
Electric Baseboard Heaters
Electric baseboard heaters are zonal heaters controlled by
thermostats located within each room. Baseboard heaters contain
electric heating elements encased in metal pipes. The pipes,
surrounded by aluminum fins to aid heat transfer, run the length
of the baseboard heater's housing, or cabinet. As air within the
heater is warmed, it rises into the room, and cooler air is
drawn into the bottom of the heater. Some heat is also radiated
from the pipe, fins, and housing.
Baseboard heaters are usually installed underneath windows.
There, the heater's rising warm air counteracts falling cool air
from the cold window glass. Baseboard heaters are seldom located
on interior walls because standard heating practice is to supply
heat at the home's perimeter, where the greatest heat loss
occurs.
Baseboard heaters should sit at least three-quarters of an inch
(1.9 centimeters) above the floor or carpet. This is to allow
the cooler air on the floor to flow under and through the
radiator fins so it can be heated. The heater should also fit
tightly to the wall to prevent the warm air from convecting
behind it and streaking the wall with dust particles.
The quality of baseboard heaters varies considerably. Cheaper
models can be noisy and often give poor temperature control.
Look for labels from Underwriter's Laboratories (UL) and the
National Electrical Manufacturer's Association (NEMA). Compare
warranties of the different models you are considering.
Electric Wall Heaters
Electric wall heaters consist of an electric element with a
reflector behind it to reflect heat into the room and usually a
fan to move air through the heater. They are usually installed
on interior walls because installing them in an exterior wall
makes that wall difficult to insulate.
Electric Thermal Storage
Some electric utilities structure their rates in a way similar
to telephone companies and charge more for electricity during
the day and less at night. They do this in an attempt to reduce
their "peak" demand.
If you are a customer of such a utility, you may be able to
benefit from a heating system that stores electric heat during
nighttime hours when rates are lower. This is called an electric
thermal storage heater, and while it does not save energy, it
can save you money because you can take advantage of these lower
rates.
The most common type of electric thermal storage heater is a
resistance heater with elements encased in heat-storing ceramic.
Central furnaces incorporating ceramic block are also available,
although they are not as common as room heaters. Storing
electrically heated hot water in an insulated storage tank is
another thermal storage option.
Some storage systems attempt to use the ground underneath homes
for thermal storage of heat from electric resistance cables.
However, this requires painstaking installation of insulation
underneath concrete slabs and all around the heating elements to
minimize major heat losses to the earth. Ground storage also
makes it difficult for thermostats to control indoor
temperatures.
Any type of energy storage systems suffers some energy loss. If
you intend to pursue an electric thermal storage system, it
would be best for the system to be located within the
conditioned space of your home, so that any heat lost from the
system actually heats your home, rather than escaping to the
outdoors. It would also be best to know how quickly heat will
escape from the system. A system that leaks too much heat could
cause control problems, such as the accidental overheating of
your home.
Control Systems
All types of electric resistance heating are controlled through
some type of thermostat: baseboard heaters often use a
line-voltage thermostat (the thermostat directly controls the
power supplied to the heating device), while other devices use
low-voltage thermostats (the thermostat uses a relay to turn the
device on and off). Line-voltage thermostats can be built into
the baseboard heater, but then they often don't sense the room
temperature accurately. It's best to instead use a remote
line-voltage or low-voltage thermostat installed on an interior
wall. Both line-voltage and low-voltage thermostats are
available as programmable thermostats for automatically setting
back the temperature at night or while you're away.
Since baseboard heaters supply heat to each room individually,
they are ideally suited to zone heating, which involves heating
the occupied rooms in your home while allowing unoccupied
sections (such as empty guest rooms or seldom-used rooms) to
remain cooler. Zone heating can produce energy savings of more
than 20% compared to heating both occupied and unoccupied areas
of your house.
Zone heating is most effective when the cooler portions of your
home are insulated from the heated portions, allowing the
different zones to truly operate independently. Note that the
cooler parts of your home still need to be heated to well above
freezing to avoid freezing pipes.
Electric heating is any process in which electrical energy is
converted to heat. Common applications include space heating,
cooking, water heating and industrial processes. An electric
heater is an electrical appliance that converts electrical
energy into heat. The heating element inside every electric
heater is simply an electrical resistor, and works on the
principle of Joule heating: an electric current through a
resistor converts electrical energy into heat energy.
We have a large selection of
electric heaters for your home at heateroutlet.com
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