Habitat "Goes Green" on Nantucket

 

 

• “Integrated Project Planning.” We have oriented the home to take advantage of the solar energy available (due south). We took great care in “siting” the home and left as much natural vegetation as possible. We also designed an efficient “small house” that has two of the three bedrooms below grade with a full walk out patio area. Having living space below grade will help keep the space warm in the winter and cool in the summer.

 

• “Durability” – durability under the LEED program means evaluating risks that affect long-term maintenance and performance of the home. In our case, weather and heat loss were the greatest concerns. Using ICFs (integrated concrete forms) for the wall system and super-insulating the roof system helps with both issues. ICFs are very durable in hurricane conditions and have higher R-values than typical 2x6 batt insulated walls. They also help minimize air infiltration, the number one cause of heat loss in any home.

 

• “Energy and Atmosphere” – LEED is highly focused on energy and the Monohansett home was designed to outperform a typical “code-built” home by 35-40% as far as energy consumption. Habitat will use the Energy Star for Homes framework for insuring that the “thermal envelope” meets LEED standards and our third party consultant will inspect the work to insure we get it right!

 

In addition to using ICFs and super-insulating the roof system, the Monohansett home will have a solar thermal heating and hot water system with three sets of Sunda vacuum tubes on the roof, which helps reduce the energy load. 

 

Since we’ve reduced the overall energy requirement of the home, we can use a smaller, more energy efficient boiler to back-up the solar heating system. Using radiant heat in the floors allows us to operate the overall heating system at a lower temperature, thus saving more energy.

 

Using Energy Star rated appliances and electrical fixtures will further reduce this home’s “carbon footprint”.

 

• “Water Efficiency” – It is hard to believe that LEED gives credit for NOT putting in irrigation, but we’ll take points where we can get them. In addition, we will use water efficient plumbing fixtures such as “dual flush” toilets, and low flow showerheads and faucets. Perhaps on the next house we can even harvest some rainwater.

 

• “Materials and Resources” – Reducing construction waste is a big focus area, especially during the framing stage. LEED requires we make a detailed list of framing materials we need and not to exceed this by more than 10% (the implied waste factor). Our plan is to order our lumber in small quantities so weather exposure doesn’t ruin it. 

 

LEED emphasizes the re-use and recycling of building materials and “local sourcing” (500 mile radius). It discourages the use of exotic woods, such as mahogany decking, unless it is FSC certified. For this reason, we are going “old school” and using Douglas Fir for all our decking. We have already received doors to recycle and many great donations, such as a brand new dual flush toilet and three Kohler bathroom sinks still in the box!

 

• “Indoor Environmental Quality” – After energy considerations, IAQ is the most emphasized piece of the LEED framework. We’ll be doing a “blower door test” to insure our building is “tight” in order to conserve energy. Once we are tight, we have to insure the indoor air is fresh and we’ll do this with an ERV (energy recovery ventilator) and Energy Star rated bath fans and range hood. An ERV takes stale (but heated) indoor air and trades it for clean (but cold) outdoor air, transferring the heat between the two so we use less energy providing this fresh air. 

 

For those with allergies or suffering from asthma, flushing out the building with fresh air before move day and the use of low VOC paints and sealants protects the air quality in the home. Hardwood floors will be used throughout as carpeting traps dirt and other irritants. To prevent dirt from entering the home, we’ll install “walk off mats” at each entry (basically a grate in front of each door). We also have an area where they can change and store shoes so less gets tracked in to begin with.

 

• “Awareness and Education” – Building a green home is great in concept but LEED also emphasizes educating the homeowner on how to operate the home after it is built. Having the homeowner participate in the construction process is a great way to begin the training. We’ll also provide them with a personalized “manual” with all information about products and appliances and we’ll train them on how to maintain the home.

 

LEED also requires program participants like Habitat to help educate the community. Contact us with any questions you have about green building or this project so we can do our part to spread the good ideas that have been shared with us!

 

Follow these links to learn more about  the U.S. Green Building Council and the LEED process.