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Confused About Voltage, Wattage, and BTUs?
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When performing home upgrades or buying new appliances such as
heaters, volts, watts, and BTUs should be factors to consider.
Some of you may have noticed that the outlet used to plug in your
desk lamp may not be the same as the outlet behind your
refrigerator, and without understanding volts, watts, and BTUs, you
could be stuck with a heater that doesn't produce enough heat to
warm your area, or worse yet, you may find yourself with a heater
that won't fit in your standard two-pronged outlet.
Voltage
Voltage is measured as the root
mean squared value between two slots or holes in an electric outlet
of the sort typically mounted in a wall, and the purpose of an
electrical outlet is to provide an area for you to plug in
electrical appliances. Most
standard power outlets in the United States are of the 120 volt
variety which have spots for two plugs and are rated for 15 amps.
Therefore, for these standard outlets, you will be able to use
any of the standard 120 volt
electric space heaters. However, do not exceed these
ratings, as the outlet
could be damaged and start a fire. In addition, if your outlet
is only rated for 15 amps, you cannot have a 14 amp heater and other
appliances running at the same time on the same circuit.
With that in mind, larger
appliances, including garage and industrial heaters, are powered
through 240 volt plugs, and cannot be powered through standard
plugs. If they were fed by a 120 volt supply, they would need
more than 20 amps of current running through the wires. In
other words, the voltage from one hot wire to the other (called line
to line voltage) is 240 volts, and the voltage from either wire to
the neutral center-tap (called line to neutral voltage) is half
that, or of the 120 volt variety as discussed above. These 240
volt outlets can also be found in garages, building sites, and other
industrial areas.
Here are examples of a 120 volt plug and a 240 volt plug:
Although a 240 volt
electric garage heater is significantly more efficient and
powerful than a 120 volt space heater, a garage heater may not be necessary for your home.
Most space heaters are 120 volts, but some wall heaters designed for home use
are rated at 240 volts and are just as powerful as garage heaters.
Watts
On the other hand, a watt is a unit of power equal to one joule
of energy per second. In terms of wattage, almost all 120 volt
space heaters are rated up to 1500 watts at the maximum setting, and
there is a 10/1 ratio of watts to square feet heated.
Therefore, a 1500 watt space heater (120 volts) will be able to heat
an area of 150 square feet, and a garage heater rated at 5,000 watts
should be able to comfortably heat an area over 400 square feet.
Therefore, if you want to heat your 450 square foot living room, you
would need to purchase three space heaters for adequate heating.
BTUs
A BTU is a unit of energy that is used globally
in heating and air conditioning industries, but is not commonly used
elsewhere. Nonetheless, in North America, the term BTU is used to describe
the power of heating and cooling systems such as heaters and air
conditioners. When
used as unit of power, BTUs per hour is the commonly used term, and
this refers to the amount of heat required to raise the temperature of
one pound of water by one degree Fahrenheit. To convert watts
to BTUs and vice versa, here are the conversion ratios:
1 watt
= approximately 3.41 Btu/hour
1000
Btus/hour is approximately 293 watts
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