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I recieved this from my frugal living email, seems like it may be helpful info.
by Gary Foreman
Will an electric space heater reduce her natural gas bill?
I live in the Midwest and am bracing for the high cost of
heating my home this winter. My question is about buying/using
a space heater. Is there a way to find out if running an
electric space heater would be cheaper than the gas I use to
heat the home? Is there a formula for this? How would I figure
it out. I've taken all the other precautions such as
insulation, furnace tune-up, weather-stripping etc. I figure I
can keep the heat turned to about 67 degrees, but a space
heater might be good for the family room and kitchen, which
are the areas that we use the most.
Cheryl R.
Cheryl appears to be serious about reducing her heating bills.
And, she's right. According to the Federal Trade Commission,
nearly half of our utility bills goes to heating/air
conditioning. So controlling those expenses is worthwhile.
Cheryl can compare heat generated from gas or electric. To get
a fair comparison, we'll determine the cost to generate one
million BTUs of heat with both fuels.
A furnace with a seasonal heating efficiency of 80% will use
12.5 therms to produce the million BTUs. MGE (Madison Gas
Electric in Madison, WI) was charging consumers $1.50 per
therm in October 2005. We'll use them as our example. At a
cost of $1.50 per therm, heating with gas would cost $18.75
(12.5 therms X $1.50).
An electric heater would consume 293 kilowatt hours to produce
the million BTUs. At a cost of $0.11 per kWh (also from MGE),
that's $32.58.
So heating with electric is more expensive than natural gas.
And, that's usually the case since a lot of electric is
generated by burning natural gas.
But, Cheryl's recognized that gas vs. electric is only half of
the equation. Could heating a smaller area (kitchen/family
room) with a higher cost fuel (electric) be a good idea?
In our example, electric generated heat is 70% more expensive
than gas generated heat ($32.58 / $18.75). As long as her
kitchen/family room area is less than 30% of the cubic footage
of her house, she'll save money by using the space heater to
heat it and turning down the thermostat on the furnace.
Remember that this is just an example. We've made some
assumptions. For instance, furnaces are measured based on
their AFUE rating (Annual Fuel Utilization Efficiency). It's
also known as "seasonal heating efficiency." We chose a
furnace rated at 80% efficiency. Cheryl's could be more or
less efficient. That would affect how many therms of gas are
consumed.
The selection of space heaters will make a difference, too.
There are a number of types available.
According to the Missouri Department of Natural Resources, a
radiator-type heater could be best for Cheryl. It works well
in a room that gets constant use. And, since the surface area
isn't extremely hot, there's less danger of someone (think
children) getting burned.
There's also a formula that Cheryl can use to figure the cost
of running a space heater. She'll need to know the size of the
space heater in watts. Divide that by 1,000 to get kilowatts.
So a 1500 watt heater is 1.5 kilowatts.
Multiply the answer by the number of hours per day the heater
is in use to determine how many kilowatts are used per day.
Suppose that it's running from 8am until 10pm. She'd multiply
1.5 kilowatts by 12 hours and be using 18 kilowatts per day.
Her electric bill will show how much she pays per kilowatt.
Let's use our $0.11 rate. The 18 kilowatts per day multiplied
by $0.11 costs Cheryl $1.98 per day to run the heater.
Make no mistake, the furnace is the most efficient way to heat
the entire house. But, according to the National Association
of Home Builders, the average home is 2,200 square feet.
That's a lot of space to heat.
And, if you'll study your home, most homes do not have someone
in every room 24 hours a day. Each family has a pattern of
use. One or two rooms might be in use for much of the day.
Other rooms rarely are used except for sleep. Cheryl might
find that she can lower the thermostat on the furnace to 60
degrees and use space heaters to raise the temperature in
occupied areas.
Chances are that a lot of us don't want to go through all the
calculations. You really don't need to. If you only have one
or two rooms occupied, it will almost certainly be cheaper to
keep your thermostat lower and put a space heater in the
occupied rooms. Just remember to take the appropriate safety
precautions when using space heaters.
_________________
Gary Foreman is a former financial planner who currently edits
The Dollar Stretcher website <www.stretcher.com> and
newsletters.
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