Now that cold weather has descended upon us rather early and abruptly, it's time to get back to the basics so that we can best prioritize energy conservation improvements.

Look at the Attic First

In more than one article, I have emphasized the stack effect that takes effect as the outdoor temperatures drop. Buoyant warmed air increasingly pushes out at the top of the house and is replaced with cold air entering at the bottom of the house. The stack effect works 24/7 and does not stop until spring, when indoor temperature is about the same as outdoor. This is in large part why the attic is the best place to start saving.

If you have only 6 to 8 inches of fiberglass batts in your attic floor, you can save a lot by improving on this insulation. Sealing all potential air leakage points prior to adding or replacing insulation is important. For example, pull up the batts and foam seal areas of air infiltration. Blown cellulose fills in gaps well and provides a continuous thermal barrier.

Alternately, you could use only foam to both seal and insulate if you lay down a thick enough layer, 2 to 6 inches, which will give you a very predictable R-value, the heat resistance transfer value. If you have a finished attic with cathedral ceilings, with fiberglass batts and knee-walls, there are effective measures you can take that will result in significant savings and are, unfortunately, too variable to go into here.

Seal Air Leaks

Air sealing not only the attic, but at the basement level is well advised. Up to 40 percent of your energy loss is attributable to air leaks. Typically, foam sealing at the rim joist and the penetrations that run from the basement up into wall cavities and at chimney chases is effective.

After sealing the big leaks, interior caulking around windows, doors and through electrical outlets is helpful. When air sealing is done, particularly in the basement but generally in all cases, combustion safety testing should be conducted using state-of-the art testing equipment.

Maintain Adequate Ventilation

As you seal your home, it is very important to make sure that you have enough ventilation to maintain healthy indoor air quality. Moisture generated in the house from multiple sources is one of the dominant pollutants that should be controlled to ensure building durability.

Houses today — new and old — generally rely on natural ventilation. The main drawback of natural ventilation is lack of control, which may result in wasted energy due to excessive air infiltration in the winter and periods of inadequate ventilation at other times.

It is much better to have mechanical ventilation to ensure that indoor air quality is sustained. Maintaining adequate ventilation can be achieved by simply installing a timer or upgrading a bathroom fan. Heat recovery and energy recovery ventilation systems are effective and adaptable to forced-air heating systems.

Think Twice about Window Replacement

The glut of window replacement advertising this time of the year is misleading and typically does not represent the most cost-effective improvement one can make to save energy. Consider replacing windows only after you have done more cost-effective energy improvements, such as sealing the attic and basement.

¢¢¢

Tim Gould is director of Energy Egghead (www.EnergyEgghead.com), an Amesbury-based home improvement company that provides thorough energy audit and conservation services.