Buzzword: Zoning

What it means. Don't confuse this week's Buzzword with school or community zoning. Rather, in the context of heating and cooling, zoning refers to dividing a home into two or more areas where you set different temperatures. Historically, zoning was more common in homes with a hot-water boiler system than in those with a forced-air furnace system. But as houses bulked up in recent years (thanks in part to the McMansion movement), the need to zone even forced-air-heating systems increased. Besides having more interior space to heat and cool, big houses are more likely to have living spaces with different exposures. To keep these rooms from getting too hot or too cold on certain days, multiple distribution systems are needed to control the flow of conditioned air.

Zoning is pitched as a way to not only make your home more comfortable but also to save you money by letting you reduce the heating or cooling to seldom-used spaces. Some manufacturers and retailers also tout zoning by suggesting that you can save by running a space heater or pellet- or wood-burning stove in a frequently occupied room and turning down the heat with your thermostat (see video, right) in other parts of the home.

Why the buzz? Residential heating costs for the 2008-2009 season are projected to be higher than for last season, according to the Energy Information Administration and, says the National Oceanic Atmospheric Administration, the lower 48 states will experience 2.4 percent colder temperatures this winter.

Those figures might make zoning a more tempting proposition. And, in fact, zoning has its place in certain situations, including where one room has very different heating requirements from others in a home. "A room with lots of glass or a bedroom built over a garage could both be candidates for zoning," says Buck Taylor, a heating professional and consultant for the U.S. Environmental Protection Agency.

But for retrofit scenarios, the question of whether it pays to implement zoning depends largely on the accessibility of the hot-water pipes (for a hot-water system) or ductwork (for forced-air system). On a forced-air system, if the central air conditioner and furnace share the same distribution system, balancing the airflow correctly can be even trickier and costlier. 

"For homes with a forced-air system, adding zoning is number 11 on the list of things I'd do [to lower energy costs]," says Harvey Sachs, a senior fellow at the American Council for an Energy-Efficient Economy. He suggests you put your money into insulation, windows, and other forms of weatherization. (Read our advice for cutting your heating bill and enhancing the value of your home.) Taylor agrees, even for homes with a boiler: "Every dollar should be spent in the shell of the house, reducing how much heat is required in the first place, before you start trying to solve problems with mechanical systems."

Chandler von Schrader, head of the U.S. Environmental Protection Agency's Home Improvement with Energy Star program, adds ductwork sealing to the steps you should take before zoning your HVAC system. He notes that duct leakage is in the 30 to 35 percent range for many homes. Correcting the problem can lead to significant savings and enhanced comfort. "Unfortunately, sealing ducts is dirty, nasty work, crawling around attic crawl spaces," Schrader says. As a result, it's a lot easier for contractors to simply zone the system. "But that doesn't correct the root cause of the problem," Schrader adds.

As for zone heating with a fireplace, fireplace insert, or wood or pellet stove, that's a smart move only if your home is buttoned up tight and the fireplace is more efficient than your heating system. If your gas fireplace is 70 percent efficient and your furnace is 85 to 90 percent efficient, you're probably better off running the furnace.

Bottom line, zoning is seldom the cure-all that some heating-equipment manufacturers would have you believe. So work with a trained professional to get a comprehensive home-energy audit, including a residential-load calculation, and determine the best approach to improving the energy efficiency of and comfort level in your home. Find a qualified heating pro by reading this story and visiting the Residential Energy Savings Network.—Daniel DiClerico

Essential information: Learn how to save hundreds on your energy costs, and discover the differences between energy savers and every hogs.

Comments

[nathan carter]

i was thinking of adding a forced air damper zone system to my home to save money and make my home more comfortable. do these systems work as well as i have been told by hvac contractors