Clients often ask us this question. Or, more frequently, “I’d like
to incorporate some environmentally-conscious elements into my home. How do I do that?” These questions are near and dear to us and we have spent many years coming to an understanding of what matters most in green building. Here are some of our thoughts on the topic.
The average home size in the U.S. in 1940 was 1100 square feet. The average family size in 1940 was 3.67. Those numbers have changed. As recently has 1997 they were 2150 and 2.64 respectively. In many parts of the country the average square footage of new construction is often-times much higher than this. We are interested in turning these trends around.
We are inspired by Sarah Susanka’s Not So Big House philosophy. Susanka posits that smaller homes are better suited to meet our needs. Saving money on the added materials involved in building a bigger home can be put to better use in higher quality materials and better more efficient design.
Fewer materials, lower embodied energy, less cost to maintain, heat and clean.
In the United States almost 50% of our carbon emissions comes from the construction and operation of our buildings. With climate change and peak oil upon us, it is of paramount importance that we design and build super-efficient, high-performance homes.
High-performance buildings in this climate are designed to rigorously retain heat energy. A minimum R-40 and R-60 thermal performance respectively on wall and roof assemblies and a very low rate of air infiltration are at the core of this reduction in heating loads. At the Garland Mill we shoot for less than .6 air changes an hour (ACH) at 50 Pascals of atmospheric pressure as measured on a blower door test. This aggressive air sealing goal coupled with high R-value assemblies and triple pane windows allow us to dramatically reduce the amount of heat required to keep a home warm through our harsh winters.
The added cost to this robust envelope is mitigated by a big reduction in the size of the heating system. Essentially, we take money from the heating budget and add it to the envelope (windows and wall and roof assemblies). The bulk of a home’s fuel consumption is used to heat the building. This is where the greatest gains in efficiency can be made.
A highly air-sealed building requires a mechanical ventilation system. We typically use heat recovery ventilators (HRV) to achieve this ventilation. HRVs use heat in stale moist air exhausted from kitchens and bathrooms to preheat incoming cool fresh air. The system then provides this fresh air directly to where people are in the home—living rooms and bedrooms.
Other opportunities for improving efficiency in homes come from domestic hot water (DHW) and electrical use for lighting refrigeration and entertainment. We typically specify low wattage CFL and LED light-bulbs, low-flow faucets, 1.0 gpf toilets and 1.5 gpm shower heads. We use meters to allow homeowners to monitor their energy use. Knowledge is power.
Local Materials. The timber in our frames is locally harvested and sawn on our water-powered sawmill. We recently bought 30,000 board feet of premium eastern white pine from a local logger. The timber was harvested 8 miles from our mill. The same logger sold us 10,000 board feet of eastern white pine just last year that was harvested 1½ miles from the mill. When the saw mill is not operating, the water from the Garland Brook powers an electric generator to produce power that we sell back to the grid. Using local materials in all phases of construction is a priority for us.
Wherever we can, we use salvage materials. On a large scale, we can reuse entire structures, turning old barns into new homes or studios. On a smaller scale, old panel doors and salvage wood for floors add beauty and warmth while conserving materials.
Our last three projects have taken advantage of salvage rigid foam insulation. This foam has allowed us to triple the insulation in the basements of our homes without tripling the bottom line for our clients.
We store our salvage materials in a large, timber framed barn next door to the mill. The barn was built by one of the first owners of the mill in 1902 with timber cut from the mill. The barn has not been in use for two decades and was falling into disrepair. We’ve undertaken to repair it in exchange for materials storage. It currently contains salvage windows, timber, tubs, and foam.
Recycled. We make an effort to use recycled materials where appropriate. We recently discovered a gypsum wall board that uses recycled drywall. Like salvage materials, this keeps waste out of our landfills.
Non-Toxic Materials. We are committed to using Low Volatile Organic Compound (VOC) paints, sealers and binders. The Advantech subfloor and sheathing we use has no urea formaldehyde binders in it. The Sherwin Williams paints we specify are a no-VOC paint. American Clay, used in our last project is a wall treatment that is not painted and has a much lower embodied energy than standard mud and tape or hard plaster options.
For those clients who have incorporated all of the above greening measures, we recommend taking the next step to renewable energy production. We have experience with photo voltaic solar panels on both grid-tie and battery storage systems. With the new federal alternative energy rebates, as well as NH, VT and MA alternative energy rebates, these systems are becoming remarkably affordable. Two of our last projects use ground source heat pumps (GSHP) for primary heating. We are also investigating air source heat pumps or mini-splits for their ease of installation, relatively low cost and maintenance.
Case Study. For an illustrated case study of one of our high-performance buildings, take a look at our Lancaster Low Energy Home.