Building a LEED Home

Interested in hearing the architect for the LEED home speak in depth about his design?  Ian Parlin, of Richard Renner Architects, is giving a a talk next week on September 14th at 7pm.  Contact FW Horch, a sustainable supply store in Brunswick, for more details. 

LEED Project Focuses on Zero Energy

Things are really shaping up on site now, all framing is nearly complete so it is possible to get a feel for the building mass as well as the interior spaces.

Early in the design process we discussed options for renewable energy sources but were concerned about the initial cost. Recently Wright-Ryan contacted Energyworks of Liberty, Maine to develop a system for solar generated electricity and hot water that is affordable, efficient and works well with our design. Solar systems in this climate are more complicated that in southern climates because of the extremes between winter and summer. In the summer the increased exposure to sun leads to the generation of more electricity and hot water than the house can use, so systems are in place to deal with the excess.

Because the solar water heating system is designed for the cold winter conditions in Maine, there is the problem of too much hot water being generated in the summer. To deal with this excess the garage floor slab is designed to function as a heat dump. Whenever there is too much hot water in the system it will get diverted into a secondary loop of pipes cast into the concrete garage slab. There is no insulation under the slab, and the ground temperature is cooler than the air temperature in the summer, so heat will be transferred into the ground rather than making the garage too hot.

The solar electricity system has a grid-tied inverter so any time the home is generating more electricity than it uses it will send power back into the Central Maine Power grid for others to use. The home's electric meter will measure both incoming and outgoing electricity and the owner is only billed for the balance. The homeowner will see reduced electric bills in the winter and possible no bills at all in the summer. This system has the benefit of allowing your neighbors to benefit from the clean energy created on site!

Architects Comments

Here are some images from a recent site visit. Mike’s crew is working fast to make up for some lost time due to the bad weather we’ve had recently so things are changing on a daily basis. The triple-glazed fiberglass windows had just arrived on site the day before my visit so by the next time I go back I’m sure they will have a few in place.

From the interior you can see some of the advanced framing techniques which save materials and actually contribute to a better insulated building. Headers over window and door openings in the exterior walls are kept to the outside face of the wall to allow insulation on the inside, and in non-load bearing exterior walls no headers were used at all thus allowing maximum insulation. Roof rafters, wall studs and floor joists are all aligned vertically to transfer loads directly to the foundation which also makes the system more efficient.

The exterior shot is of the north side of the house where there are few window openings, this is part of the passive solar design to reduce heat loss. Windows on the south elevation are protected by overhangs and exterior sunshades, these were sized to allow maximum sunlight into the house in the winter and to shade the windows in the summer. The large steep roof plays a role in the active solar design by supporting the photovoltaic cells and solar water heating system on the south-facing roof pitch.

I’ll be back on site next week and will return here with more photos and another update.