Some people swear by things like caulking their window and door frames and putting up window plastic. But other people say none of this saves much energy. What’s the truth?

The truth is that these are a good ideas but not the only ideas. These steps have small energy savings compared to, say, comprehensive air sealing and insulation upgrades. You hear a lot about these smaller steps because they’re a relatively easy and inexpensive way to block obvious drafts.

The main cause and remedy for those drafts, however, isn’t at windows and doors. It’s most likely in the attic, where air can exit the house if the attic floor isn’t sealed and insulated. Because we spend time near windows and not in the attic, most of us have never felt the constant draft that can occur in a leaky attic. But the attic is where the bigger energy savings can be found.

How does a leaky attic floor create drafts in the rest of the house? Well, think of a house with a leaky attic floor as a drinking straw, with air instead of liquid being pulled out of the top. The pull at the top of a house draws in outdoor air from anywhere it can, like gaps around exterior doors and windows and numerous other places, including gaps in basement walls. Sealing places where air comes in is sensible, but you won’t solve the main problem or get significant energy savings until you also seal the top of the house.

The most effective approach, with the biggest payoff, is to have a professional find and fix air leaks throughout the house and then make sure that you have sufficient attic insulation. Home Performance with ENERGY STAR contractors are trained to do just that and more. If you’re interested in finding a Vermont contractor, visit www.efficiencyvermont.com/ho meperformance.

- Li Ling for The Home Team

What’s a net-zero home? Does it really use no energy? Does it cost more to build?

A net-zero home is a house that produces as much energy as it uses. This home generates the energy it needs from renewable resources like wind, sun, and water. The house design focuses on minimizing energy needs through air sealing and insulation, energy-efficient lighting, appliances, spaceheating, water-heating, and ventilation systems. Also, a thoughtfully-chosen building site and orientation are needed to enable you to make optimal use of renewable resources.

The key factor in preventing net-zero construction from being more expensive than standard construction is house size. In other words, if you take the average-size new U.S. house (2,438 square feet) and use the above approach to designing and building it, then yes, it will cost more to build; not only for the house itself but for the larger heating systems and renewable energy system that will support it. But if you apply netzero design techniques to a small house, (say 1,200 square feet or so), it is possible to build at a cost comparable to that of standard small-house construction.

I want to point out that, to determine the cost-effectiveness of net-zero construction, (or any energy-efficient construction), any higher initial expenses need to be weighed against the lower energy bills that you can expect year after year. Also, keep in mind that the most cost-effective time to incorporate energysaving and/or renewable-generating elements into a home is in the design and construction phase. To determine the costs and benefits for the house you have in mind, I recommend starting by contacting Efficiency Vermont about the Vermont ENERGY STAR Homes service and contacting Renewable Energy Vermont at www.revermont.org. Best of luck!

- Kathleen for The Home Team