Turn off the pilot flame of your gas furnace in the summer

Most gas furnaces in operation today still have a continuous pilot flame. Turning off the pilot flame in the summer is easy to do and well worth the effort, but very few people do it, either because they don’t know how or aren’t aware that they should. Once you are familiar with the procedure, it only takes about 2 minutes per year to to do and will save anywhere from $30-$60 per year depending on your furnace, your location, and gas prices). It will also reduce your greenhouse gas emissions by 0.15 to 0.30 tons per year.

I live in a moderate climate (Vancouver, BC, Canada) and only require artificial heat about 7 months of the year (from mid October to mid May). For the other 5 months of the year I turn my furnace off completely, including the pilot flame. There are occasionally some cold days during that period but we’ll usually just wear extra clothing and leave the furnace off. Throughout much of the US the heating season is shorter and your potential savings are even higher.

Extinguishing your pilot flame

To turn off your furnace completely, look for a valve in the gas line to the furnace. Simply turn the valve handle so it is angled 90 degrees to the pipe as shown below. If you like, you can check your furnace to ensure the pilot flame goes out. Note that there is no danger of a gas leak if someone inadvertently turns the gas back on. There is a thermocouple sensor in your furnace that will prevent gas from flowing if the pilot flame is out.

Gas line valve in off position Gas line valve in on position
Gas line valve in off position Gas line valve in on position

Re-lighting your pilot flame

To turn your furnace back on, turn the valve handle parallel to the pipe as shown in the second image above and re-light your pilot flame following the furnace manufacturer’s instructions. If you don’t have the manual for your furnace you can probably look it up online or follow the general instructions below.

  • Make sure the gas valve is turned on (lever should be parallel to the pipe)
  • Turn the furnace dial to “pilot” position
  • Press and hold the thermocouple bypass button (otherwise no gas will flow since the thermocouple will detect that there is no pilot flame).
  • While holding down the bypass button, hold a lit lighter or match at the location of the pilot flame. If the gas valve has been turned off for several months, there will be air in the pipe and it may take some time for this to be expelled before the pilot flame lights.
  • After the pilot flame lights, continue holding down the bypass button for 30 seconds or so to allow the thermocouple to heat up. Then release the button.
  • If the pilot flame goes out when you release the button, try lighting it again and wait longer. If you still can’t get the pilot flame to stay lit without the button depressed, there’s likely something wrong with your thermocouple.

That’s all there is to it. If you really want to save some money, consider switching to electric space heaters. In spite of the apparent higher cost of electricity, you can save money because electric space heating is so much more efficient than combustion based central heating methods.

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There are 5 comments on “Turn off the pilot flame of your gas furnace in the summer”

  1. Heath said ... 2008-12-01 at 1:32 pm

    This also adds life to your furnace by reducing the corrosion caused by the moisture from the pilot light exhaust. I forgot and left mine on this summer. I vaccuumed a lot more rusty scale out of the burner area than I did last year when I turned it off. I use a vacuum to clean out the burner area in preparation for the heating season. This is another easy way to make your furnace more efficient and less likely to produce carbon monoxide.

  2. Mark - Web HVAC said ... 2009-01-26 at 9:10 am

    Very good post! One other thing we try to do anytime we turn a gas valve on or off, is to take a bottle of soapy water and spray it around the valve, looking for small leaks.

    Good post! Bookmarked and will share with my own readers!

  3. Cole said ... 2009-08-12 at 12:21 am

    very helpful. Now I don’t have to worry about poisoning myself. Exactly what I was looking for

  4. Tom said ... 2010-11-09 at 8:07 am

    Even though electric heaters are theoretically 100% efficient, they actually use a lot more energy due to the inefficiencies of electricity production and distribution. For electric space heaters to make sense, you have to be heating a small area compared to the entire building. You wouldn’t want to heat your entire house with several space heaters. If you leave your furnace off and move a space heater to wherever you need it, that could have savings. Now time to turn on my pilot light!

  5. Brent said ... 2011-05-25 at 5:30 am

    Yes! I turned off the pilot to my gas log set. It was pretty worthless because its a vented gas log setup… It produced very little heat. I also use propane for my on demand water heater. I was amazed at how much longer my propane lasts! That little pilot flame can burn up a lot of gas.

    I’ve been on a mission to cut my energy expenses… Please feel free to drop by my page and check the things I’ve been working on. http://streetjesus.blogspot.com

    Cheers!

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