The following are the 7 steps we believe to be the crucial elements of building a high-performance home, aggregated to give you a peek into what the differences are between a traditionally built home and a high-performance home. This process is one that eliminates not only excessive utility consumption but also the problems that can arise from a home that is not running at peak efficiently such as drafts, inconsistent heating, and excess money spent on heating and cooling. We have found these steps the best way to get your home’s running costs down, while providing un paralleled comfort and security for you all year round. We utilize tried and true techniques, approaches, and materials that we have found to be the best performing and most cost-efficient ways to achieve long lasting results.
We have seen trends come and go but we know the following concepts are at the core of what makes our work sustainable as well as environmentally sound and are proud to be able to share our years of experience with you.
The following steps are what we believe to be the crucial elements of building a high-performance home, aggregated to give you a peek into what the differences are between a traditionally built home and a high-performance home. This process is one that eliminates not only excessive utility consumption but also the problems that can arise from a home that is not running efficiently such as drafts, inconsistent heating, and money spent re-insulating or replacing heating systems. These steps are what some consider the ‘low hanging fruit’. We consider them the best way to get your home’s running costs down, insulated properly, and performing efficiently for you all year round. They utilize tried and true techniques, approaches, and materials that we have found to be the best performing and most cost-efficient ways to achieve long lasting results.
We have seen trends come and go but we feel that the following concepts are at the core of what makes our work sustainable as well as environmentally sound and are proud to be able to share our years of experience with you.
Extreme care is taken during the design process to orient the building in a way that it takes maximum advantage of the sun. South facing windows are the largest. Window shades are used to block unwanted summer solar gain, yet allow solar gain in the winter. Wall, roof, or lawn areas are dedicated to PV solar collectors. Energy models are used to determine heat loss and BTU’s needed, for correctly sized heating systems.
Our buildings are sealed to the point that if inverted and tossed in the ocean the house would float. Any air leaks, as small as a pin hole, are identified and sealed before insulation begins. This is achieved with Blower Door testing, thermal imaging cameras, smoke stick, and the back of our hands to feel for leaks. This is probably the hardest part of the process, but the rest of the systems will not work properly if this step is skipped or done haphazardly. The new “MUBEC standard code” requirements have a target of 3 ACH (air changes per hour?)
Wood and steel are very good conductors of Electricity, they are also good conductors of Thermal energy. Meaning, if you have a wall stud that is in contact with the cold outside and the other face of it is touching the warm area inside, you are losing heat to the outside and gaining cold on the inside. This effect can be seen on the exterior walls or roof of a standard building during a cold morning after frost has accumulated on the building. Often you can see the outline of the wall studs or rafters clearly as these areas have melted the frost first because of the heat loss through the rafter/stud. There are various ways to reduce thermal transfer of energy through the structural components of a house. One widely accepted method is Stress Skin Panels, or foam insulation sandwiched between 2 layers of plywood, then hung on the house’s frame. This method poses serious problems in the water sealing aspect; typically the foam is petroleum based, and has structural ramifications also. The method we prefer is the double stud wall method, composed of two exterior walls separated by a 4″ space between them. Both walls and the space are then filled with Dry Dense pack insulation made from recycled paper. The thermal bringing effect is eliminated.
The double wall system once filled with cellulose gives us r-45 walls and r-70+ roofs. This one is simple: the more insulation the less energy needed to keep the building warm. Triple glazed windows are often also used to mitigate some of the heat loss through them. The windows are still however the weak point in the envelope, with the best ones on the market at only r-5, so careful design is needed to minimize their effective energy losses.
These houses need very little supplemental heat, in fact if you take it a little further and go to passive house levels they need none. In passive houses the heat from the appliances, sun, and occupants are enough to keep the buildings at 67 deg. without an additional heat source. The associated costs and accompanying size and design limitations to get from net zero to passive house however can be a deal breaker, so we believe “Net Zero” is the standard that every new house can be easily built to. Since net zero supplemental heating needs are so small, simple electric baseboard and air source electric heat pumps are used.
The heat pumps also have A/C built in, and are 3 times more efficient than simple electric heat in KW used /BTU produced as they simply collect and condense heat from the outside environment, rather than create heat. Ground source heat pumps can also be used (Geothermal), but in our climate they have been proven to be less effective for heating than the air source when installation costs are factored. Hot water is produced with electricity only by a combination of on demand tank less electric water heaters and heat pump hot water heaters. We feel there is no need for oil, wood, coal, or propane, all of which have health and environmental impacts when burned, and high costs. We encourage you to look to the sun for your energy needs!
Since our houses are so tight they do not “breath” on their own. We use air to air exchange systems to control air quality. These systems draw fresh cold air from the outside and suck stale hot air from the inside. The two are passed by each other in a heat exchanger and the heat is extracted from the stale air and passed to the fresh air before it enters the building. These systems can recover 95%+ of the heat energy. Additional features are HEPA filters, dehumidifiers, and humidifiers, which will make your indoor air cleaner than outdoor air. In most standard homes the air quality inside the home is 7 times worse than outdoor air, not in net zero homes, indoor air is actually cleaner than outside air.
Two components are needed for this phase, Photo voltaic solar panels and a Net Metering grid tied power system. We primarily use PV electric panels, as they have gotten very efficient and much cheaper in the last few years. The 3 story 1400 square foot Rockland “Breakwater House” has only 9 panels to generate all the energy needed to heat and power the house for the year. The 3 story 7500 square foot Knox St. “Sail Lofts” 9 unit apartment building in Thomaston has 50 panels for normal heat and power requirements. These solar systems have dashboards so you can see your daily use and generation rates, on your smart phone or computer.