Many gas fireplaces, stoves and inserts operate with a standing pilot light. What does a pilot light actually do? Is it a good idea to turn it off during the warmer months? How expensive is it to keep it going year-round? If I turn it off, is it difficult to re-light? If you have ever wondered about the small, blue flame in your gas fireplace or stove, you should find this information helpful.
WHAT TYPE OF IGNITION SYSTEM?
Most burners on gas fireplaces will be a tube style or ceramic burner. The burner will include the gas valve, various fittings and a control module. When the remote control is pressed, the wall switch clicked on or the thermostat on the wall starts calling for heat, the gas valve opens and gas is allowed to flow to the burner.
Right before the burner is the pilot light. The pilot light can be a “steady-on” pilot, or an ‘intermittent” or an electronic ignition system. The later type of pilot light is only on when the valve is open and the fireplace is operating. A millivolt valve utilizes a pilot light that is always lit. So, this discussion “should I leave my pilot light on year-round” will be confined to a millivolt ignition system. Intermittent Pilot Ignition (IPI) systems can be set for the pilot to run continuously, but are normally operated in the auto-shutoff mode.
THE FUNCTION OF A PILOT LIGHT.
There are two main functions of a pilot light. One is to generate electricity; millivolts. That is, thousandths of one volt is what opens and closes the gas valve. The pilot’s second purpose is to ignite the gas once the valve has been opened.
DOES A PILOT LIGHT USE MUCH GAS?
So, should we turn the pilot off during the warmer weather? Just how much gas does a pilot light consume?
Most pilot lights will consume about 600 BTU’s of gas/hour. With 24 hours in a day, that’s roughly 14,400/BTU’s each day. Figuring 30 days, a pilot light will use approximately 432,000 BTU each month.
Natural gas (NG) is measured in therms. Each therm equals 100,000 BTU’s of heat. 432,000 BTU’s equates to 4.3 therms of gas. Finally, apply a rate with each therm of natural gas. At $.90/therm you’re spending about $3.90 each month to keep the pilot going. At $1.20/therm, the monthly cost would be about $4.95.
The same exercise can be used for LP gas. LP is measured in gallons. There’s 92,000 BTU’s in one gallon of LP. 432,000 BTU’s represents about 4.7 gallons of LP. At $1.10/gallon, roughly $5.20 is the cost each month of keeping your pilot light on. At $1.30/gallon, you would spend approximately $6.10 every month.
ADVANTAGES VS. DISADVANTAGES.
There are pro’s and con’s to leaving a pilot light on year-round in your fireplace, stove or insert. The biggest advantage of course, is if you’re not using the fireplace for five months, you could save $20 or $30.00. However, the small amount of heat that the pilot creates helps to keep the inside of the firebox dry. This is especially helpful if you live in a damp or humid climate. Another advantage to keeping the pilot going is to keep small, silky spider webs that can block orifices and require a service call to clean and correct. If you have this problem, $20 to $30.00 won’t even get a service tech in your driveway!
Shutting off the pilot light off means it will need to be re-lit in the fall. It’s not a difficult process. The procedure is outlined in your owner’s manual. However, some homeowners can struggle getting the pilot going again.
Many professional fireplace service technicians prefer a millivolt system over an IPI system. Millivolt systems have been around for years. The technology is much simpler, it’s easier to trouble-shoot and diagnosis problems and if anything needs repairing or replacing, a millivolt system is less costly to fix.