Energy Retrofit Project to Create Energy Efficient (and affordable!) Housing

We recently filmed a tour of the CLAM house, an energy retrofit project at Point Reyes. Terry Beneke, who was one of the energy retrofitters who worked on the CLAM house, recently underwent energy training through the CBPCA's HERS program.  The CLAM project was a recent opportunity for him to put what he learned into practice.

CLAM, Community Land Trust Association of West Marin, is a pretty amazing organization dedicated to purchasing existing houses, subsidizing their energy retrofits, and returning them back to their communities as energy efficient affordable homes.  The organization has been in Marin for 8 to 9 years, and it was founded by local residents through a grass roots movement. CLAM is community supported through the door to door fundraising efforts of its members.  To qualify for CLAM housing, one has to make 60% or less than the average home's income .

There were multiple energy retrofits that were done to this home to make it more air tight and energy efficient.  A fireplace that was causing considerable heat loss was removed and replaced with an insulated air tight wall.  The home's walls were insulated using foam insulation and an OSB skin, a cheaper alternative to plywood made of glued together wood chips, was installed as an air tight barrier behind the insulation in order to seal the framing.

Another modification made to the home was raising the crawl space by 2 and a half feet, so that whoever needs to work in the space will have a clean and comfortable space. If it's messy and tight, contractors will want to get out right away and probably do a bad job.

Next up for CLAM... an even MORE energy efficient house. The FIRST passive solar house of its kind will be undergoing construction behind the CLAM project featured in our video. Check back soon for even more!

All three videos-

Part 1

Part 2

Part 3

Other quick notes on the project:

Took all the old wires and plumbing and threw out the antiquated. Rewired and plumbed everything into the 2 by 6 joist cavity, about 70 years old. After everything was tucked into joist cavities. If there is a leak, one would have to open the joist cavities; there will be an instruction manual as to how to do it. Have few punctures in the wall cavity as possible; for instance, there was one for tubing of hot water. The OSB was put on. The seams were taped with something called pukee, duct sealer. Taped the seams with sheetrock tape and pukee. On the edges, foam was applied, an orange foam. Air sealing is made on the bottom and it continues out to the walls. Insulation, blown in cellulose, was installed behind the joist. - Back porch of clam house: OSB framing is used on the walls. Reduced amount of wood, and increase amount of insulation in the wall. The studs are 2 ft. on center. Under every window, where ordinarily there is a cripple underneath the 2 by 4, metal clips are used instead; one doesn’t need all that wood to support the window frame. The plywood on the outside holds it up. - Compared to traditional framing: current frame was 23% reduction of 2 by 4s usage. 1 inch of wood has R value of one. - Blown in cellulose is used. It is blown in from the outside. The framing were netted and subsequently a hole is cut and a blower tube is inserted to fill up the wall with cellulose, which does have some boron in it but is inflammable. Fiberglass is hard to cut around the wire, cellulose packs around everything. The old insulation; Terry showed where heat loss would occur in the old framing, mainly 2x4's (16 inches on center). - single top plate, rafters line up with the studs. Eliminates the need for double top plate, rafter transfers to the stud. The double top plate acts as a header; completely legal. Save on labor and material for construction. - ERV: Energy Recovery Ventilator. Recaptures more moisture. Miniature heat recovery system. The house is so airtight now, that you get into problem of getting in outside air. ASHRAE standards: if below 0.35 ACP, you have to bring in outside air. If bathroom fan, the bathroom fan will take any air in the house and blow it outside. The ERV does the same thing, but a little differently. On the way out, the air goes through heat exchange. The heat exchanger takes out the heat and reintroduces it to the heat envelop. Pulls 66% of the heat out the air. Bath vent will take 100% of heat out. If doors and windows and closed, the ERV is ideal. - Peter, before and after, CBPCA plug in. The test equipment. CFM 1303 afterward 300. Reduce house pressure to 50 pascals. 1303 CFM leaked in to maintain 50 pascals. 1 CFM is one basketball volume-wise. With the walls and floors done, not yet the attic, CFM reduced to 330. ACH 0.61 (2/3 of air was being excahgned) and knocked down to 0.15. Specific Leakage Area: size of holes, put them together into one hole. For each square foot, there would be 6.6, that has been reduced to 1.7. Passive house is in progress. When it is done it will showcase even more Energy Efficiency.