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[an error occurred while processing this directive]Ask Mr. Electricity about saving on heating costs

This page has random questions & answers only.
You'll probably find my
general page about heating to be more useful.

The most important questions

I have a two and a half story house and want to reduce my heating bill.  What is the best temperature to keep my thermostat at in the winter to reduce costs? -- George W., Cary, NC

You really have to ask? As low as it will go. To save the most money you should turn the heat off completely.

If you complain that you won't be comfortable without any heat, I'll remind you that you didn't ask about your comfort level, you asked what temperature setting would reduce costs the most.  That temperature setting is the lowest one possible.  If that's too low for your comfort then set the thermostat to the lowest temperature you are comfortable with.

That level is something known only to you, not to me.  You can't find your own comfort level by writing to some guy on the Internet.

Does a central-air system work faster if you set the temperature higher than what you want?  For example, let's say it's 60° now, and I want to heat the house to 68°.  If I set it to 75° will it get to 68° faster?  I'm notgonna use my heater until you clear this up so please answer soon because I'm cold. -- I. P. Freely, Springfield

Your heater does not heat faster if you set the temperature higher.  The heater has only two modes:  on oroff.  If it's on, it's heating.  If it's off, it's not.  So just set the thermostat to 68°.  (Or be tough and set it to65°.  You can take it.)

If you set the thermostat higher, not only does your house not get warmer faster, but you'll forget to turn it off when it hits68° (or 65° if you're not a wuss), and then you'll be paying to heat your home beyond what you intended.

By the way, the same is true when you're using the AC:  setting the thermostat lower than what you want doesn't cool your homeany faster.

When I am not in a room I have developed a habit of turning off the heat in that room by turning the vent off.  Will this save loads of on my gas bill or am I wasting my time? -- Nancy Mandell, [xxx]

Uhh.... wait a minute, you work for a company that sells home heating systems and you're asking me?!

Anyway, first let's get our terms straight.  The vent is the opening that sucks air from the room back into the heating system. The register is the opening where air gets pushed into the room. So it sounds like you're really talking about "closing a register", not "turning the vent off".

The idea of course is that you're trying to avoid paying to heat a room you're not using, and hoping the rest of the house gets warmer quicker so the thermostat shuts the system off sooner. Unfortunately, this just promotes duct leakage and can actually damage the heating system, so there are no savings to be had here.(LBL)  So keep your registers open.  A better way to save is to shut off the central system completely and use space heaters in just those rooms that you'reusing.

I have an oil-filled radiant heater with a switch for 600 or 900 or 1500 watts.  Which uses less energy to heat a cold room to a certain temperature, 600 or 900 watts? How much does it cost to run a heater? -- Sunflower Christine, Salada, CO

They're both the same. There isn't anything magical about this. At the 900-watt setting you'll use 50% more energy than at 600 watts but it will take 50% less time to get the room to the required temperature.

(The nit-picky will note that at 600 watts the room is being heated more slowly, so there will be more time for the heat in the home to transfer out of the home, and thus it will theoretically take a little more time to get the room to a certain temperature, but the difference is probably negligible.)

To figure how much it costs to run see the cost page.

Space heaters

Which is the better portable electric heater: oil-filled or fan-blow? -- B. T. Wanter

Depends on your criteria. They both generate a similar amount of heat and use a similar amount of electricity to do so (1500 watts). Oil-filled heaters take longer to heat up a room, but they're safer because no one part of them gets hot enough to start a fire. They pull that off by having a greater surface area -- a little bit of heat is spread around the entire heater itself. Another advantage is that they operate silently.

If you want safety or quiet operation, go with oil-filled. If you don't care about those things and want speed, go with fan-blow.

I don't use a heater at all until it gets below 55 degrees inside and my fingers are too cold to type, and I don't use a heater while I'm sleeping no matter how cold it gets. (Yes, I can see my breath in my house in the morning.) When I do turn on a heater I use the Heatsafe fan-blow ribbon heater I got from Sears for $45. Incidentally, if you ran a 1500-watt heater continuously it would use 1100 kWh per month (1500 watts X 24 hours X 31 days), and at 10˘/kWh that would run you $110/mo.

I'm a rep in a home improvement store and electrical staff are saying that a 1500W portable heater running on 120V consumes more electricity than a 1500W baseboard heater running on 240V. They insist that the meter reads the energy and that an appliance like the portable heater will be charged at the 240V rate at the meter. Me, I think a watt is a watt. -- Ric

You're right, a watt is a watt, as far as how you're charged for electricity. All utility companies charge by how many kilowatt-hours you use, not by voltage.  If two appliances use the same number of watts then you'll be charged the same amount for using either of them, regardless of how many volts they use.

Remember that Volts x Amps = Watts.  A device that runs on 240V draws half as many amps as a similar wattage device that runs on 120V. Bottom line, watts are watts, and watts are what you get charged for.  Volts don't matter, in practical terms.

I'm single and live alone in a 3000 sq. ft. house. Would it make sense for me to turn off my central heat (gas-powered) and use an electric space heater to heat my room?  I figured I could wear warm clothes while awake for the short time I am actually home and awake. I am trying to save because my utility company charges me twice what my energy usage is, in the form of "delivery charge" which means my typical summer bill is like $30 for energy use but $100 total.  Or, would the electric heater use more energy than my gas furnace, to the point of being ineffective? -- Randy Blake Jr.

Yes, you will almost certainly save money by using an electric heater to heat just your bedroom vs. a gas furnace to heat the whole house. It's easy to confirm this, even before you get your electric bill: Try it the new way for a couple of days and note how much electricity you used (by checking your electric meter), then compare the use of that much electricity to the cost of gas for the same period.

One thing, since you have a central system, the door to your bedroom has a gap on the bottom to let the air flow from your room back to the central heat system. But if you're heating just your own room, heat will escape under the door. To prevent this, install a door sweep on the bottom of the door, or put a rolled-up towel there. Department stores and catalogs actually sell cute little flexible cloth "logs" to seal up the gap at the bottom of the door.

I read your article on saving electricity with interest, untill you got to space heaters.  Clearly you don't live in Canada.  Your advice on heating with space heaters is wrong/poor if you live somewhere that needs heat enough to stop the pipes from freezing or that needs the space heaters on constantly in order to heat the room that you are in.   I lived for a short time with a very bad landlord who insisted on heating only with space heaters, we froze, the house froze, the food froze and worst of all the heating bill tripled!  Much of your advice is good, but I don't think that you understand heating in a cold climate. -- John Barclay, Canada

  1. Who on earth said it's a good idea to heat up your whole house just to keep your pipes from freezing?! Instead of keeping your pipes from freezing the most inefficient way possible, consider using heat tape (which, at 3 watts per foot, will let you warm 50 feet of pipe for a mere 150 watts), and good insulation on top of that. You say you have more than 50' of pipe? It doesn't matter. It's always cheaper to warm just the pipes rather than your whole house just so that a little bit of that heat makes it to the pipes.
  2. My advice for using space heaters instead of central heat was to heat only the part of the house that you're using instead of the whole house. If you're gonna heat the whole house with space heaters instead of just part of it, then of course there's no advantage, and you might as well use central heat.
  3. If a space heater can't heat the room you're in, it's either too small or you have serious insulation problems.

Heating large areas / multiple parts of a house

In our house now we have electric heat with thermostats in each room. My son (it's his house) keeps only the thermostat in the living room on, set at 60 degrees F.   That's it.  I believe we would be warmer, and spend less, if we put all thermostats at 64 or 68, so that the heating system doesn't continuously work to heat the whole house from one thermostat.  Am I wrong? -- Lauren MacArthur, Waterbury, CT

Yes, I'm afraid you're wrong. The warmer you want your house, the more energy it's going to take to make it so. Heating the house to 60 degrees takes X amount of energy, no matter how many heaters are contributing to the effort. Heating it to 64-68 takes considerably more energy.

When you have multiple heaters going it simply shortens the amount of time before you reach the desired temperature, but you use the same amount of energy. You can run one heater for three hours or three heaters for one hour, it makes no difference.

In fact, when you want to warm the house to a specific temperature, using one heater will use less energy than using several. That's because the room with the thermostat will be warmer than the rest of the rooms, so the thermostat will think everything's warm enough, and it will shut off.

I don't turn on my own heat until it gets below 55.

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What is the best way to correct uneven heat distribution through the air vents in a house. We have some rooms that blow more air than other rooms. The rooms that have low volume air being blown are very cold. -- J. J. Mitchell

The way to correct uneven distribution is to adjust the dampers inside the ducts (provided that your ducts have them).  Dampers are plates inside the ducts that control how much airflow each leg of the ducts gets, and are adjusted with a lever outside the duct.  Since you're unfamiliar with dampers I suggest you have an HVAC professional adjust these for you (and show you how to do it for the future).

If the air being blown from some registers is cold then you probably have leaks in your ducts and need to have them repaired.


I know you don't see benefit in wood stoves in basements, but, I must tell you, we had one in our old house, and we just cracked the cellar door, and had so much heat we had to open windows, frequently. We didn't use our oil heat at all.  -- Lauren MacArthur, Waterbury, CT, Jan. 2005

Most of the heat generated there is wasted since nobody lives in the basement.  If you used the same kind of fuel to heat your living space directly then you'd need a lot less fuel to do so -- whether it's wood, oil, or electricity.

Somebody told me it is better to heat your basement so your first level stays warmer, and you don't spend any more energy. It would make more sense to me that keeping the basement cool (not too cold though so the pipes don't freeze!) would use much less energy. What do you think? -- Derrick

I think it's ridiculous. You'd use a lot of energy in the basement to prevent a little loss of heat on the first floor. Obviously most of the energy spent in heating the basement is spent in heating the basement.

Eclectic questions

I'm looking for something to provide insulation for light switches/electrical outlets on exterior walls. I read about foam gaskets that you insert behind plate but I can't find them. -- Lori, St. Louis

These should be easy to find at hardware or home improvement stores. If your store doesn't have them then ask them to order some, or try another store.

I have a gas forced air furnace in my attic for the upper levels of my home.  The return vents and registers are located on the ceiling in each room.  Isn't the hot air from the registers just getting sucked back up into the return vents?  Seems like I need to run the heat a lot longer to get the heat to reach the floor.  Is this an efficient setup, and if not, what can I do to make it more efficient? -- Jack Sayers

It's not as bad as you think, but you can definitely make it better.  First, your heater fan should be powerful enough that the air coming out of the vents goes almost all the way down to the floor.  If it's only coming out a few inches then you have a leaky duct or some other problem with your system that you should get fixed.  Next, regardless of how hard the air comes out, you should use ceiling fans to get the warm air off the ceiling.  Just put them on the lowest speed.  If there's a fan right above you and the breeze is cooling you off, then reverse the fan direction so it blows up, which will bounce the warm air back down.  If you don't have ceiling fans then either install them, or get a floor fan and aim it up at the ceiling to distribute the air.

How much heat do you lose by opening a door in the winter?  For instance, if it's 68° inside and 20° outside, how much heat do I lose leaving the door open for 1 minute bringing in groceries?  I realize house size and configuration—and even wind direction—matter, but is there a general rule of thumb? Andrew Tubbesing, Medina, OH

This type of measurement is next to impossible to make, and there's no rule of thumb I know of.  Here's the best way I can think of to estimate it.
1. Turn off the heater.

2. As soon as the temperature goes down to 67, turn the heater back on and record the amount of time it takes to get back to 68.

3. Wait until the heater goes off and the temperature has fallen back to 68, in case you overshot it.

4. Open the door for one minute, then close it.

5. Wait a couple of minutes for the cold air to mix in your home. If the temperature hasn't dropped to 67, then repeat steps 4 and 5 until it does.

6. Divide the number you got in step 2 by the number of times you opened the door. That's the approximate number of minutes you have to run your heater to compensate for one door opening. Since this is such a crude way of estimating it I wouldn't be surprised if the figure were off by 400% or more.

Of course, the temperature in your home is dropping even if you don't open the door. We could make the following additions to the above process to try to account for that:

  • Insert Step 3.5: Record how long it takes for the temperature to drop from 68 to 67 on its own, without opening the door.
  • Insert Step 5.5: Record the number of minutes that elapsed from the first door opening to the last door close.
  • Insert Step 5.6: Subtract the number of minutes in step 5.5 from the number you got in step 3.5, then divide by the number in 3.5. In other words: (#3.5 - #5.5) ÷ #5.5.
  • Add Step 7: Multiply your answer in step 6 by the number from step 5.6. This attempts to account for the fact that the temperature would have dropped anyway during the experiment, even if you hadn't opened the door. However, even this method still has all the fine precision of a jackhammer.

To figure out how much this costs you for an electric heater, find out how many kilowatts your heater uses then multiply it by the number of minutes you got in step 6, then divide by 60 minutes/hr., then multiply by how much you're paying per kilowatt hour.

If you have a gas or oil heater you'll have to check with the manufacturer to see how much fuel it uses per minute, and with your fuel company to see how much that amount of fuel costs.

Hi! I have radiant heat (in the ceilings) in my apartment.  Last month's bill said I consumed over 907 kilowatt hours MORE than last month, and I was told this is because the weather was colder.  I have two bedrooms, a living room and a tiny bathroom and kitchen, not much square footage.  I always keep the heat on at 68 degrees; my room and the bathroom at 60.  Can such an increase be possible? I'm very afraid of this month.  My bill was never that high for December before.  Any advice for people with electric heat?  Note, my refrigerator is at least 25 years old.  Many thanks for your advice! -- Carole Koudsi, Massachusetts

Good question! First off, we can discount your refrigerator, because it's the same refrigerator you had last month.  It may be inefficient, but it's not suddenly 907 kilowatt hours more inefficient this month.  And it wouldn't use 907 kilowatt hours total for the whole month by itself, even if you had the door open 24/7.  (Check out the How much your appliances use page.)  If your refrigerator uses 700 watt-hours (the least efficient part of the range), and it ran continuously, it would use only 504 kWh a month (700 watts x 24 hours/day x 30 days).

It would be helpful to know how much energy your heating system uses. For two small bedrooms and a living area, let's make a ballpark guess at 6 kWh per hour.  If you used 907 kWh extra last month, then you used about 30 kWh extra per day.  At 6 kWh, that means your heater would have had to be on an average of 5 hours a day more than the previous month. (30 / 6).  That's certainly possible as we head deeper into winter.

A few possible tips: First, if you have ceiling fans and you're not using them, use them. Put them on the slow speed to get the warm air off the ceiling and down to the living area. If you don't have ceiling fans, get a box fan and aim it at the ceiling.  Second, if your thermostat lets you turn off the heat to individual rooms, do so.  Heat only the room that you're in at the moment.  If you can't do that, then turn off ALL the heat and try using an oil-filled, plug-in, radiant heater instead.  It runs on electricity, but since it's intended to heat only one room at a time, it'll use less electricity than your system which heats your whole apartment at once. Good luck!


We have a two-story house with a gas furnace.  Recently my sister-in-law started drawing on the walls and our kids got into some fights at school.  We then started eating more vegetables but our neighbor took a job in another state without saying goodbye.  Subsequently I dialed the thermostat up a little bit although around the same time aliens kidnapped our dog Rex and replaced him with an exact replica.  So, do you think our heater is working properly? -- Kenneth


Also see my general page about heating and heating costs.


Last update: June 2013.
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All advice is given in good faith. We're not responsible for any errors or omissions. Electricity can kill you; if you're not competent to work on your electrical wiring then hire a professional to do it.
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