High Performance, Hyper Energy Efficient Home

High Performance,  Hyper Energy Efficient Home

High Performance in the Hills of Vermont We had a lot of fun building this super insulated, high performance, hyper energy efficient home in 2012. Many unique design features both inside and out were incorporated into the construction many of which were designed by the owners Lisa and James themselves, so we developed a very close, collaborative relationship with them. The home presented some interesting challenges. The first was hitting ledge only 18 inches down when we started excavating, so we had to completely redesign the foundation. Ultimately, we elected to build a super insulated floating or Alaskan slab which has no frost walls. Instead of pinning the frost walls to the ledge, which would have created a huge thermal bridge, the Alaskan slab allowed us to create a foundation fully insulated from the ground with no thermal bridging, an important standard in high performance, hyper energy efficient homes. We used 8 inches of high density EPS foam board (two layers of 4″) to insulate under the slab and 6 inches along the slab edge to fully encapsulate the slab and eliminate thermal bridging. The foam panels were used as the concrete forms and were set up so that the edge of the slab was 12 inches in thickness while the rest of the main slab was 5″. All plumbing and wiring conduit was roughed in before pouring the concrete. We framed the house using a double 2×4 stud wall technique used on many super insulated homes. This creates a 12 inch thick wall cavity with a 5 inch space between the walls creating a substantial thermal break between the inner and outer walls. We used Igloo dense pack cellulose, our favorite insulation material, to insulate the walls. We designed the roof trusses with 18 inch raised heels to ensure the thick insulation was continuous from bottom plate to top plate and created a 20 inch deep cavity in the trusses so we could super insulate to R-70 all the way to the roof peak. This also created some attic space inside the thermal envelope for storage and the air exchange, heat recovery ventilation system. The owners wanted the house to have a post and beam look to it to match their barn. Because we used conventional engineered roof trusses, we elected to add custom milled rafter tails which we bolted to the trusses. Tongue and groove pine was run over the top of these to create a soffit. Since the rafter tails penetrate through the exterior sheathing of the house which is the air barrier, we air sealed these penetrations with 2 part spray foam from the inside. This can also be done with special European air sealing...

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Super Energy Efficient, Custom Net Zero Home

Super Energy Efficient, Custom Net Zero Home

This new 3 bedroom, 2 1/2 bath home we built in 2013 for a young energy conscious family brought together all of the best elements that can go into a net zero, high performance, super energy efficient home in Vermont; double wall framing, simple, cozy and efficient design, heat pump heat, cooling and hot water, plentiful natural light through beautiful tilt and turn triple pane windows, thermal mass in the floor of the main living space, natural, renewable materials and efficient air exchange heat recovery ventilation and a full array of Solar PV’s on the roof. We took the best of what we had learned on previous high performance projects and applied them to this project and another, similar home we built concurrently that year (see Another High Performance Home in Vermont). Super Energy Efficient Foundation       We started this home by insulating under and around the footings with 4 inches of EPS foam so the home would have minimal thermal bridges from the ground all the way to the roof. We built our own foundation out of insulated concrete forms (ICF’s) and poured our own concrete walls. This gave us a super energy efficient full basement with R-30 walls with a 6 inch rebar re-enforced concrete core insulated on both sides. The rim joist of the floor system is also insulated on both sides with 2 inches of EPS set in the same plane as the ICF’s and then added 4 inches of air sealed polyisocyanurate foam board on the inside. The inside is finished with drywall which is screwed directly into plastic ties inside the ICF’s and finished on the outside with a fiberglass mesh re-enforced stucco/parging product called Sider-Crete. We used a typical double 2×4 wall framing system for the exterior walls with a total depth of 12 inches (R-42 insulated with dense pack cellulose). We placed the second floor framing on the inside 2×4 wall so that we could completely dense pack around the rim joist and eliminate the typical air leakage and low R- value issue that plague conventionally framed homes. We used regular roof trusses designed for a flat ceiling with 18 inch raised heels to allow for ample insulation over the top plates of the walls. Ceiling R- value is 85 with 24 inches of loose fill cellulose. When we set the trusses, we continued our 1/2 inch exterior zip wall sheathing up to the trusses, then under the trusses and across the entire ceiling. This enabled us to air seal the entire second floor ceiling before any interior partitions were built eliminating all the air leakage that is typically associated with interior walls and attics.  Because of the level of air...

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The “Almost” Passive House

The “Almost” Passive House

This new 3 bedroom, 2 1/2 bath home project, located in Charlotte, Vermont, was built using a modular construction approach and was designed using Passive House energy performance criteria. The goal was to meet the Passive House performance standard.  After many weeks of design work completed by Pill-Maharam architects, blasting the site,  setting the foundation and working closely with Preferred Building Systems in Claremont, New Hampshire, the 4 modules went into production and arrived on the site to be set on a beautiful, sunny spring day. Once the modules were set and the roof assembly completed, it was all ours to complete – exterior trim and siding, porches and decks, foundation parging, kitchen installation, interior window trim, flooring, etc. Passive House Foundation Details The foundation footings were set on top of 4 inches of high density EPS foam and completed wrapped on all sides with 4 inches of EPS. The foundation had 4 inches of EPS foam installed on the exterior walls, 2 inches on the interior along with a 2×4 framed wall filled with spray foam to achieve an R-45 rating. 12 inches of high density EPS foam were placed under the slab. The wall assembly utilized double 2×4 framing with a 10 inch cavity for dense pack cellulose with 4 inches of polyisocyanurate on the exterior making the wall assembly about R-62. The flat trussed ceiling has 30 inches of loose fill cellulose for an R-value of 108. Not your typical house! Mechanicals- Heat Pumps, Air Exchange-Heat Recovery Ventilator, Solar Hot Water, Solar Electricity The house uses a Zehnder 350 air exchange-heat recovery system. We installed a soil exchange loop around the footings ( 2 laps of 1 inch Pex tubing filled with anti freeze) to plug into the optional Zehnder heat exchanger that pre-warms and cools incoming air and helps to dehumidify the air. The hot water system is a two panel solar hydronic system with a 80 gallon storage tank and a 50 gallon standard electric hot water heater for back up. The house is heated and cooled with a single point Mitsubishi Hyper Heat Mr. Slim FE-18 heat pump. A 3 inch concrete slab was poured and polished in the main great room as thermal mass. In the laundry area on the first floor, a condensing dryer was used to avoid having to vent to the outside creating a major penetration of the thermal envelope. As of this posting, we have been monitoring the performance of the house closely and it has been performing quite well with overall temperature variations through the house only being a few degrees. More specific performance data will be posted in a future update. We call it the “almost”...

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Energy Star, Neighborhood Farmhouse

Energy Star, Neighborhood Farmhouse

We started building this 5+ Energy Star house in the fall of 2009 and completed it in the late winter of  2010. Built for a family of four near downtown Shelburne, Vermont,  it is about 2400 square feet with 3 bedrooms, 2.5 baths, a large 2 story mudroom with sky lights that links the main house to both floors of the 2 car garage. The mudroom contains a laundry facility, large closet and room for built-in benches. There is also a full basement and study. This house has room to grow, including a huge 675 square foot space above the garage that can be finished and another 550 square feet of basement space that has radiant floor heat in the slab already (finished in the spring of 2014). Radiant heat was installed on the first floor, with baseboard on the second floor. A beautiful wood burning built-in stove was installed in the living room with a unique one piece limestone facing. The wood stove heats the entire downstairs comfortably. The floors and cabinets are all red birch and counter-tops granite. Cellulose was used to insulate the house and, as we always do, an air exchange/heat recovery system was installed. Custom tile work was done in the master bathroom steam shower, all the bathroom floors and mudroom. The master bedroom suite is quite spacious with a full cathedral ceiling, walk in closets and spacious bathroom. The outside decks and porches all feature Brazilian Paulope with tongue and groove pine ceilings. Cost was about $162.00 per square foot (2009) not including blasting and excavation to build the house. This does not include design work,  land and permits....

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Energy Star House Sited for Natural Light

Energy Star House Sited for Natural Light

Energy Star, Energy Efficient This couple bought a beautiful 5 acre lot in North Ferrisburg with the vision of creating a simple homestead with extensive gardens and an orchard. First they needed a house and garage. The house site is well suited for southern exposure which affords plentiful natural light inside the house and passive solar heating. It features a master bedroom and 2 studio spaces upstairs along with a generous sized bath with built in tub and separate shower. Downstairs is an entry porch that leads into a mudroom and then into the great room which holds the kitchen, dining area and living room. At the center of it all is a beautiful soap stone woodstove. Towards the back of the first floor is a spacious guest room with a cathedral ceiling. This room and the adjacent bathroom can be closed off with a pocket door creating a private, quiet space for its occupant. The home has a full basement with a bulkhead leading out towards the garage. The garage features a large second floor which can be finished at some point to create a spacious studio for gardening classes. Other features include bamboo and marmoleum floors, red cedar decks and porches, pine soffits and porch ceilings, low VOC paints, and maple cabinets. The home is insulated with cellulose in the walls and ceiling and has a full home air exchange heat recovery system (Venmar). Foundation walls and under slab are insulated with either EPS foam or polyisocyanurate. The home rates as a  5 star Energy Star Home. The cost of this house came out to be about $150 per square foot (not including design and site work).                    ...

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