SOLAR TODAY - June 2012

ate a continual air/moisture barrier around the entire house. The total r-value for the walls on the original part of the house is R- 36. In the addition it is R- 48.

The basement walls, which are 8-inch-wide cinder blocks, needed to be insulated in a way that didn’t consume too much interior space. We opted for a wall of 2x3 studs held 2 inches off the block walls. Then we sprayed behind and between these studs with 4 inches of bio-based, closed-cell foam. This resulted in an R- 27 basement wall, with a loss of only 4-½ inches of space.

On the original basement floor, in order to avoid losing too much ceiling height, we put down only 1-½ inches of rigid foam board (R- 7. 5) and covered the floor with plywood. The addition floor has 3 inches of foam board (R- 15) under the slab.

tom of the originals, using plywood “ties” to hold them together end to end. These 11-inch bays, and the 2x4 walls, were filled with dense-packed cellulose. To add to the roof insulation, after stripping off the old asphalt shingles, we screwed down one layer of 3-inch-thick polyiso rigid foam boards. Staggering the joints, we added another 1-inch layer of polyiso and taped all joints.

The challenge was insulating the original exterior walls, which were now stripped down to the 5/8-inch plywood sheathing. My choices were to apply two layers of rigid foam, like we applied to the roof, or to spray foam the entire exterior. My building consultant, dave raponi, suggested the latter for a better air seal and possibly less cost. one of the carpenters, Tom Cuccaro, came up with a way to frame over the sheathing and around the window/door openings so that spray foam could be applied.

Tom designed a type of secondary framing system, consisting of 2x3s attached to the exterior of the original sheathing. These nailing strips, spaced 16 inches apart, are held 3 inches off the sheathing with sections of 1-inch PVC pipe, thus creating a continual plane of space for the foam to be applied into. long screws were drilled thru the 2x3s, the pipe and plywood and into the original 2x4 studs. This also created a new framework around the house onto which our siding and trim could be nailed. Once all the framing was finished, 3 to 4 inches of closed-cell, bio-based spray foam was applied, filling all spaces behind and between the framework and creating an airtight layer of insulating foam. About 1 inch of air space was left between the foam and the outer edge of the nailing strips, creating a drainage plane. Even the addition, constructed of Durisol ICFs, was sprayed with 1-½ inches of foam to cre-

Achieving near-zero energy

originally I thought we’d be able to move into the house in four months. We started the demolition in August 2009, and moved into the partially completed house May 15, 2010 — nine months later. The solar panels were online in august, one year from our start.

It was a mad dash, but with a lot of team effort, great attention to detail and quality workmanship by all, we came close to our goal: a zero-net-energy, super-insulated, deep energy retrofit, using the “5-10-20-40-60 rule” as a guideline for insulation levels. New York State Energy research and development authority and our home energy rater/consultant gave the house an Energy Star rating of 5 stars plus, the highest tier. The blower door test revealed an excellent level of airtightness: 1.39 air changes per hour at 50 pascals. In order to keep our electricity usage down, we chose all Energy Star-rated appliances. The

In the existing part of the house, the rafters were 2x6s and the walls were 2x4s. To get a lot of insulation in this existing framework, we chose dense-packed cellulose insulation in between the rafters and in wall cavities, 4 inches of polyiso rigid foam on the roof and closed-cell spray foam covering the exterior walls. Each rafter was beefed up to 2x12 by adding a 2x6.

lighting is 55 percent CFL, 14 percent LED and 31 percent traditional incandescent. We could save even more by getting rid of all incandescent lighting and using our clothes dryer less often.

The project cost went above our projection. However, we added many features and design elements, going beyond the planned deep energy retrofit to a total renovation. The estimated cost of the deep energy retrofit portion of the renovation, including all new electrical systems, plumbing, windows, doors, mechanicals, photovoltaics, insulation, roofing, siding, the durisol addition and so on, is about $150,000. The result is a comfortable 2,200-square-foot, beautifully designed, all electric zero-net-energy home with three bedrooms, two bathrooms and two kitchens. In one year of producing electricity, from august 2010 to August 2011, we purchased about 4,100 kilowatt-hours from our electric utility at a cost of about $530 (plus $370 for taxes and delivery charges). That covered everything, from heating and cooling to hot water, cooking and laundry.

achieving near net-zero-energy was arduous, but satisfying and well worth the effort. anyone committed to transforming an older house can do it, too. It takes a lot of research, hard work and the right team of people. With the abundance of poorly insulated, in-need-of-repair homes in this country, opportunities abound to renew, recycle and retrofit. ST

Robert Ritacco has been the owner of r.J. ritacco Painting Co. since 1980, and of ritacco’s retrofits since 2010. He is married and has two daughters. robert and Wendy live in ulster County, N.y.