­

For most of us, it hasn't been that bad of a winter. A warmer than usual January, especially in the Northeast and Midwest, helped keep energy costs under control.

Natural-gas price increases, in anticipation of higher demand and supply disruptions caused by Katrina and Rita, were short-lived. By early February, utilities were notifying customers of major reductions in supply and distribution costs.

This isn't to say that many household budgets were stretched by energy costs this winter. Many owners of houses that are not properly insulated or who aren't used to conserving energy were justifiably shocked when they opened their December and February bills, since each of those months had several days of colder-than-average temperatures.

Except for those on fixed incomes, whether the poor or the elderly, these increases in utility bills have been met fairly easily, and likely will be quickly forgotten as winter turns into spring, and then into summer.

That's not a good idea. Spring and summer are when the typical homeowner needs to think about dealing with tightening up their houses to reduce utility bills. In fact, insulating a house properly works just as well for cooling as it does for heating, so tackling these projects in the spring, perhaps in conjunction with damage repair from winter storms, may at least reduce the worry levels in the fall as well as the air-conditioning bill in the summer.

One thing you should be looking at is how well your present furnace has performed this winter. If you use electric resistance heat, higher electricity prices may force you to switch to a more affordable gas or oil furnace, or a heat pump. If you have a gas- or oil-fired furnace or boiler, whether or not it should be replaced is governed by a number of factors, not only how it has performed this winter -- meaning the cost of energy -- but age and condition.

If your furnace or boiler is old, worn out, inefficient, or producing more BTUs per hour than you really need, all you do is replace it with a modern high-efficiency one. Old coal burners that were switched over to oil or gas are prime candidates for replacement, as are gas furnaces without electronic, pilotless ignition or a way to reduce the flow of heated air up the chimney when the heating system is off. This includes vent dampers or induced draft fan.

A typical heating system will last about 25 years, though some boilers can last twice that long. For example, my old house had a 100-year-old boiler that had been converted to oil from coal in the late 1940s. We changed the oil burner in the late 1987, only because the original burner was leaking and the parts for it no longer were being manufactured. Yet, with that new burner and a cleaned and turned system, the efficiency rating for the next 14 years we owned the house never fell below 88 percent.

According to the American Council for an Energy-Efficient Economy, the efficiency of new furnaces is measured by seasonal performance, or AFUE (annual fuel utilization efficiency). Many old furnaces with pilot lights have estimated AFUE ratings of only 55 to 65 percent. Furnaces that qualify for the Energy Star program must have an AFUE of 90 percent or higher.

Most new gas furnaces fall into one of two general efficiency classes. One is power combustion, which runs at 80 to 82 percent AFUE, and "condensing" furnaces, which are at least 90 percent efficient.

The council recommends condensing furnaces, except in warm climates.

Condensing furnaces are much less likely to suffer from corrosion caused by condensation in the unit or its flue and chimney. These models typically exhaust through a plastic pipe that exits through a side wall, and do not use the chimney. In some cases, a chimney liner must be installed if the chimney will still be used for a gas water heater. Few oil-fired condensing furnaces are available.

My gas condensing furnace has a AFUE rating of 92 percent, and is vented through the basement wall. The water heater is vented through a separate flexible liner through the chimney. The fireplace was converted to ventless gas logs. The damper is always open a crack when the fireplace is in use, even though the log insert comes with an oxygen-depletion sensor and a carbon monoxide detector that would shut off the fire automatically in case the room was low on oxygen.

No matter how efficient the furnace is, they don't save energy by themselves. If you house is not property insulated, the furnace will have to work hard to make you comfortable.

Energy efficiency requires a whole-house approach, something you need to take care of long before next winter approaches.

Log in to comment
­