Check Rating Of Efficiency When Installing Gas Heaters
Q: What can you tell me about natural gas fireplaces and freestanding heaters that look like wood stoves? I recently saw one at a home show. I’m interested in installing something this summer to provide supplemental heat to my rec room. We have a fireplace but it loses more heat than it contributes. I want something that’s efficient and convenient. - N.L., Spokane
A: With natural gas hearth products, you can choose from many options. You’ll find gas logs, built-in gas fireplaces, inserts and freestanding heaters. All are convenient and decorative, but not all are efficient. So it makes sense to learn about the products and shop around before making a purchase.
Evaluate efficiency: It’s important to keep in mind that, while natural gas may be cheap, it’s a finite resource. The U.S. natural gas resource (at current estimates) will last about 50 years at current consumption rates. A heater that uses gas efficiently will stretch the resource and save you money.
Since you’re looking to heat your rec room, shoot for high efficiency - 70 to 80 percent. And since you already have a fireplace, a gas insert or freestanding heater might be the best option. Both offer high efficiencies, depending on the model. An insert can be mounted inside the fireplace; a freestanding unit (depending on the size) can be mounted inside or on the hearth in front.
Not all natural gas hearth products have reliable efficiency information. Most are tested to a “decorative” standard which tells you nothing about efficiency. Efficiency information is provided when products are tested to an American National Standards Institute (ANSI) standard for non-decorative gas heaters, but only a few companies use it.
One way to check efficiency is to check for information on heat input and output in the product literature. Look for BTUs per hour. Dividing the output by the input figure will give you an estimate of the efficiency. For example, a gas heater that provides 22,800 BTUs of output using 30,000 BTUs of input, will offer a heating efficiency of 76 percent (22,800 divided by 30,000). If a product doesn’t come with this information, it’s probably designed for decoration rather than heating efficiency.
Choose blue flame: Blue flame products are more efficient than ones that burn with a yellow flame. The yellow color is achieved by starving the fire of oxygen and is done to get the aesthetic effect of a wood fire. It looks good, but the penalty is lower efficiency and soot build-up in the flue and on the glass door.
Vent-free? Some stores may carry unvented gas heaters that manufacturers claim operate at close to 100 percent efficiency. We recommend against using them except in very well-ventilated areas (such as a warehouse or shop with open windows). Natural gas combustion produces a large amount of water vapor that could cause weeping windows, mildew growth and, over time, structural damage to wood and wallboard. Some counties and cities in Washington prohibit their installation because of health safety concerns. Check with your local building department before considering a vent-free gas heater.
Control options: Gas fireplaces and heaters come with standing pilot lights or electronic ignition. The latter is more energy-efficient. Many models offer a push-button piezoelectric ignition system that starts the heater during power outages. Thermostats are a desirable feature as they allow you to select a room temperature and will turn the heater on and off as needed.
Costs and savings: Built-in gas fireplaces and freestanding heaters are comparable in cost to pellet stoves and certified wood stoves. Like wood stoves, they can reduce heating costs by allowing you to focus heat in the family room while setting back the central thermostat in the rest of the home. They aren’t affected by the wood stove law, so they can be used throughout the heating season, even during burning bans.
Shopping tips: Wood stove and fireplace shops often sell natural gas hearth products. Visit several stores. Look at heaters in operation to see how they feel and learn how they operate. Try to find a store that displays units you can operate there.
Be prepared to describe how you will use the heater (burning frequency and length of burn). Know the size of the space you want to heat. Match the heat output of the unit to the needs of the space. If you want an insert, get the measurements of your fireplace.
Insulate first: It doesn’t make sense to put an efficient appliance in an inefficient house. Before buying a gas heater, make sure your attic, floors and walls are well-insulated.
The Gas Research Institute has published a list of companies that manufacture gas fireplaces, fireplace inserts and logs. This list includes product features. For a copy, call the Washington State Energy Office’s Energy Hotline at (800) 962-9731 or 324-7980 in Spokane.
xxxx