Tuesday May 7, 2013

Wait a second. Spring has barely sprung, and you’re saying we need to start thinking about energy audits already? What’s up with that?

There are several reasons why now is a good time not only to assess how energy-efficient your house is but also to carry out weatherization projects.

Weatherization professionals have some time

Because spring isn’t a time when many of us are thinking about heating bills and how to bring them down, it’s a good time to find contractors who can do that weatherization work.

Those contractors who do general construction work may be gearing up for the summer building season, but for those specializing in energy audits and weatherization, now is a good time.

Still cool enough for thermographic analysis

Part of an energy audit may involve taking images of your house with a special infra-red camera to identify areas of excessive heat loss. Infrared or thermographic cameras show temperature differences. Taking such images of your house walls when the house is warm indoors and fairly cold outside will show visually where heat is escaping from the house.

To work well, there has to be a significant temperature difference between the interior of the house and the outdoors. The minimum temperature difference (delta-T) is 20 degrees Fahrenheit, but a higher delta-T is even better.

Even though it’s supposed to go up to the mid-70s during the days this week, it should go down into the low-40s or 30s at night. So a thermographic analysis in the evening or early in the morning can still find plenty of delta-T for the assessment.

Air tightness is key

A huge part of weatherization is tightening up the house. To assess air tightness, a blower door is used. As described last week, this is a fan that is installed in a door frame and depressurizes the house. A computer controller tells you how tight the house is by calculating how much air has to be forced through the fan to maintain a specific pressure difference -- usually 50 pascals.

Great incentives for energy audits and weatherization work

Brattleboro and a number of surrounding towns (Dummerston, Guilford, Halifax, Marlboro, Putney, Rockingham, Townshend, and Windham) are participating in the Vermont Home Energy Challenge, sponsored by Efficiency Vermont and the Vermont Clean Energy Network (VECAN).

The goal of the Home Energy Challenge is to encourage homeowners in participating towns to carry out weatherization projects to lower their energy use. The target is getting 3 percent of homes to complete weatherization projects -- or 10 percent to pledge to do so -- by the end of 2013. In my town of Dummerston, this will mean getting 24 homeowners to carry out weatherization or 79 homeowners to pledge to do so. A total of 178 homes need to be weatherized in Brattleboro (592 pledges) to meet the challenge.

Before and after blower door testing is required as part of the Home Energy Challenge, with a target of at least a 10 percent improvement in air tightness through the weatherization.

Prizes will be awarded to towns that do the best, though everyone who goes through the process will be a winner in terms of increased comfort and lower energy bills.

In some towns there are additional incentives for participation. For example, in most of the towns in our area, local energy auditing and weatherization companies are offering to conduct the audits at a lower price than normal -- typically just $250 (instead of $400 to $500). And in Dummerston an anonymous donor is adding another $100 toward the cost of energy audits for up to 24 energy audits. If interested in this option, contact the Dummerston Energy Committee (energy@dummerston.org), which is administering the Home Energy Challenge in the town.

Plenty of time to get the work done before winter

Step one should be getting that energy audit to find out what your house needs. In local Vermont towns that should cost just $150 to $250 for most houses -- an amazing bargain. If you follow through with weatherization work following the audit, most local weatherization companies will even refund the cost of the audit. There are additional incentives available as well: up to $2,500 from Efficiency Vermont and as much as $500 as a federal tax credit.

Step two should be carrying out the energy improvements. This work can include new door gaskets, weatherstripping on windows, use of foam sealant and caulk to seal cracks and gaps identified in the audit, added insulation, and perhaps other features like installing storm windows and closing off larger holes through the house envelope.

For most homes, weatherization is extremely cost-effective, with the several thousand dollar investment paid back in just a few years through energy savings. Just as important as the financial return, however, is the dramatic improvement in comfort that can be achieved through weatherization.

Learning more

Now’s a great opportunity to finally move ahead with an energy audit and weatherization -- and doing so may help your town win the Vermont Home Energy Challenge. For more information on the Challenge, including a list of participating contractors, contact Paul Cameron at 251-8135 or pcameron@brattleboro.org, or visit either www.brattleboroenergychallenge.org or www.efficiencyvermont.com.

To get some hands-on understanding of what’s involved with weatherization and home energy improvements, Paul has organized a tour of four local homes that have been retrofitted to save energy. The tour will be this coming Saturday, May 11 from 10 am until 1:00 pm, with participants meeting at the Brattleboro Food Co-op and caravanning to the four houses. Contact Paul for more information.

Alex Wilson is the founder of BuildingGreen, Inc. and the Resilient Design Institute (www.resilientdesign.org), both based in Brattleboro. Send comments or suggestions for future columns to alex@buildinggreen.com.