Some of the advice we hear about saving money on heating costs is oversimplified, marketing hype or just plain wrong, while some long-standing myths persist about keeping warm on the cheap.
For example, programmable thermostats are not the holy grail of home heating, cranking up the furnace does nothing to heat a chilly house faster, and fireplaces used as heating sources literally suck paid-for warm air up the chimney.
Duct tape? Not good for sealing ducts.
To truth-test heating advice and unveil some myths, we sought help from Max Sherman, a senior scientist at the Lawrence Berkeley National Laboratory overseeing research for residential energy efficiency. Besides being a serious scientist, he gained notoriety in the late 1990s as Dr. Duct Tape for discovering that the gray-backed sticky tape “failed reliably and often catastrophically” when used for sealing ducts.
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“It will get old and fall off after a year or so of heating cycles,” Sherman said. “Plenty of tapes are good for sealing, but standard duct tape isn’t one of them.”
Here are a few other home-heating myths.
If you enjoy the sound, smell and ambience of a wood fireplace, go for it. Just don’t think you’re helping your wallet. “A fireplace is a particularly bad way of heating your home,” Sherman said.
First, there’s paying for firewood. Then you feed the fire’s appetite for oxygen with your paid-for heated indoor air and shoot it up the chimney.
Not a recipe for financial savings.
A possible exception is if you want to turn down the heat in the rest of the house and close off and heat only one room – the one that includes the fireplace. Or, as Sherman notes, it might be a net benefit if the fireplace has sealed glass doors and “you’ve gone through the trouble of essentially turning it into a sealed wood stove … then you no longer have the nice, cheery fire you probably had in mind when you said, ‘Let’s use the fireplace.’”
These highly touted devices simply do automatically what you could do yourself, namely walk over to the thermostat and adjust it.
Many programmable thermostats require, as the name implies, programming. The simple or “dumb” ones are clocks that adjust the temperature at prescribed times – although some might come with a built-in program. “It’s definitely going to save you money in the default mode because it will turn it down at night and save energy,” Sherman said.
However, like the fireplace, a programmable thermostat might enhance your life but could end up costing you money, at least compared with diligently setting the temperature manually every day.
Sherman said his heating bill went up when he installed one. Why? Like most people, he used to turn the heat up when he got up in the morning. With a programmable, he could warm the house in advance of his feet hitting the floor. “I liked it, but it did not save energy,” he said.
And if you have a heat pump, which doesn’t work as well with widely varying temperatures, the value of a programmable thermostat can be diminished, he said. “Because of the way heat pumps work, set-back can be a difficult thing for them and may not save nearly as much.”
If you want the convenience of a programmable thermostat, remember to actually program it, or use pricier “smart” thermostats that can learn how your house works and make adjustments. The point is not to avoid programmable thermostats. They can be convenient. It’s to use them wisely to use less energy. Consumer Reports in its October issue rated models ranging in price from $50 to more than $500.
Crank it up
Something in human nature leads homeowners who walk into a frigid house to think that cranking the thermostat to 85 degrees will somehow heat the home quicker. “It is a common misconception,” Sherman said. It doesn’t work that way. Think of furnaces as light switches, not dimmers. They are either on or off. The only result of your thermostat cranking will be heating your house beyond a desirable temperature and wasting energy – and money.
Leave it up
Another common refrain is that it’s cheaper to keep your home at a constant temperature, even when you’re not home. “Almost never true,” Sherman said, noting again that houses with heat pumps can be an exception.
“If the system is running less, it means it’s using less energy,” he said. Says the Department of Energy on energy.gov, “You can easily save energy in the winter by setting the thermostat to 68 degrees while you’re awake and setting it lower while you’re asleep or away from home.” Figure you save up to 1 percent per year on your heating bill for each degree you set back the thermostat for eight hours, such as when you’re sleeping or at work. A 10-degree drop could be 10 percent savings.
Marketers of window replacements have the story half right. Replacing drafty windows with energy-efficient ones will save on energy use. But windows are so expensive, often thousands of dollars, that the break-even will be measured in decades. Among energy upgrades aimed at saving money, replacing windows might rank dead last.
“On the cost-benefit priority list, windows are usually behind air sealing, insulation and system efficiency improvements,” Sherman said. That said, if you have decided to replace windows for a different reason – perhaps cosmetic reasons or to eliminate drafts – you might as well pay for highly efficient ones.
“While replacing them just for energy may be quite costly, moving to high-efficiency windows when they need to be replaced anyway is almost always a good idea,” Sherman said. “The marginal difference is small.”
What should you do?
It’s not rocket science. Sealing gaps and cracks around windows, doors, ducts, pipe cutouts and other areas is among the most cost-effective moves. Consumer Reports says blowing sealant into ductwork, called aerosealing, is effective, albeit expensive upfront, $1,500 to $2,500 with promised savings of $250 to $850 per year. See aeroseal.com. It also says a professional energy audit can be worthwhile too, although it costs $250 to $800.
And consider changes that allow you to lower the thermostat a few degrees, including dressing for winter, which might mean wearing a sweater and slippers around the house. Electric blankets use little energy and can make it easier to lower the thermostat a few more degrees at night.
For more information and suggestions on cost-effective home energy improvements, see energystar.gov and homeenergysaver.lbl.gov. The American Society of Heating, Refrigerating and Air-Conditioning Engineers offers tips at tinyurl.com/ashraetips.