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webfish LLC
Staff member
Oct 18, 2013
Questions and Answers About Gas Fireplace Appliances

By Mary Carson, WE Associates (ed. note: Mary is a spokesperson for the Gas Industry)

Concern About a Shortage of Natural Gas ?
Can I use Propane instead of Natural Gas ?
Which burns hotter—Propane or Natural Gas ?
How many BTU’s are Hearth Appliances ?
What does AFUE mean ?
How much will it cost to burn my Gas Appliance

Q. I remember the seventies when there was a concern about running out of natural gas and homes could not be installed with gas and gaslights had to be turned off. If I buy a gas fireplace, will there be enough gas to keep it burning?

A. The question is good, the answer is great…yes, according to the American Gas Association (A.G.A.) there are more than 60 years of proved gas reserves and an unlimited amount beyond this data. These reserves are located in gas fields that have been identified and can be accessed whenever the need arises. Both the Department of Energy (DOE) and this number. Also, because of new drilling technologies, wells can be sunk deeper into the ground to allow for the availability of more natural gas. At least 90 plus percent of all gas used in the U.S. comes from this country. Only about eight percent comes from Canada and 2 percent from other countries. For your information, gaslights are now allowed in 48 states. Unfortunately, the conservation movement devastated the gaslight market. Twenty-five years ago more than one million lights per year were sold. Today that number is under 75,000. Because of a new technology that allows for on-and- off controls on gas lights, consumers are installing them at their homes, country clubs, casinos, business offices, historic sites, city streets, developments, schools, restaurants, marinas and shrines. Back in the 1800’s the first competitor to the gaslight industry was whale oil. Times have changed!

Q. Can I use propane gas instead of natural gas in gas fireplace appliances?

A. Yes, most all gas appliances, except for the new gas heat pump, can work using propane or natural gas. However, because propane is a different chemical base than natural gas (methane), there are adjustments that must be made. Usually, the orifice must be changed to allow for the higher heat value (an orifice is the opening in an orifice cap or other device that controls the flow of gas). However, some appliances are made for only natural gas or propane. As a reference, look in the A.G.A. Certification Directory, or other nationally recognized laboratory’s directory to determine which appliances are certified for natural gas and/or propane use.


Gas Fireplace - Valor
Q. Which fuel burns hotter, propane or natural gas (methane)?

A. Propane is the hotter burning fuel. Propane is a gas that is present in most natural gas and is the first product refined from crude petroleum. It contains approximately 2,500 Btu per cubic foot. Methane is the chief constituent of natural gas and has a heating value of about 1012 Btu per cubic foot. Therefore, propane has more than twice the heat value of natural gas per cubic foot.

Q. What do I need to know about Btus and gas fireplace equipment?

The average 24” set of vented gas logs burn 60,000 Btu per hour. However, smaller and larger sets are available ranging from 8,500 Btu per hour to 100,000 Btu per hour. Fireplace inserts range from 12,500 Btu per hour to 50,000 Btu or more. Vent-free gas logs and fireplaces range from 8,500 Btu to 39,000 Btu per hour. This compares to an gas oven in a range. Gas ovens automatically cycle and cannot burn more than 40,000 Btu per hour at full load. Customers may be interested to know that gas ovens do not require venting.

Q.I have been told that vent-free gas fireplace units burn 99 percent AFUE. What does AFUE mean, and what AFUE should I look for in buying a vented or vent-free product?

A. AFUE stands for “Annual Fuel Utilization Efficiency.” To understand the importance of the measurement, let’s look at a gas furnace. If the furnace burns 78 percent AFUE, this means that 78 percent of the heat is being utilized in the home and 22 percent is going up the chimney or flue. Because vent-free products do not have a chimney or flue, all of the heat enters the room, therefore their manufacturers advertise “99 percent AFUE.” If the unit is a gas fireplace insert, the AFUE measurement may equal that of a heating appliance rather than a decorative appliance such as gas logs. Gas logs give off heat, but because of the opened damper in the chimney, much of the heat goes up and out. Subsequently, the heat is radiant and warms the room…the same type of heat that comes from a cozy wood burning fire.

Q.How much will my gas fireplace cost to burn for the season?
Update: 2006 - Gas Prices are going up and down quickly as with other energy. Be sure to check the current cost in your area.

A. This is not an easy question. It depends on how much you want to burn it. Some families use their gas fireplace for weekends and others use it daily. A good estimate is about 400 hours per season. To determine the cost, multiply the Btu per hour of your unit, times the number of hours (60,000 Btu X 400 = 24.000,000 Btu). Now reduce this number to therms or cubic feet. A therm is equal to 100,000 Btu: the answer is 240 therms or 24.0 Mcf. Now look at your gas bill and find the cost of gas per therm or Mcf. and multiply the annual Btu by that number (if your gas is 1.70 a therm or $17.00 per Mcf, your annual cost would be $400.00 or about $33.00 per month on budget billing).

Here is another example: If you have a 40,000 Btu gas fireplace and only use it 200 hours, the cost is only $136.00 per year (40,000 Btu X 200 = 8,000,000 Btu divided by 100,000 = 80 therms X 1.70 = $136.00 per year or about $12 per month. The cost of gas is different in each city. Be sure to check with your gas utility or propane dealer. National numbers are available but they are not the same as your locality.
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