A decade long effort finally came to fruition in April 2018. After three designs, a recession of historic proportions, a renovation, and multiple historic commission hearings, I finally completed construction of my new home last spring.
The culmination (for now, at least) of 30 years in construction and about 17 in green building, this very traditional looking house incorporated many cutting-edge construction techniques. Starting from the bottom, instead of a crawlspace or basement, I opted for an elevated slab foundation installed inside concrete walls filled with recycled gravel. Finished with thin brick veneer, it provides a traditional look without the potential moisture problems of a crawlspace. The design is very simple – no cantilevers, vaults, or other unusual shapes that are hard to seal and insulate. The walls are insulated with Owens Corning blown fiberglass insulation and sheathed with Huber Zip-R which provides a weather barrier, structure, and a continuous layer of insulation in a single material. Over this we installed Home Slicker vented rainscreen for additional moisture protection, and Boral TruExterior siding and trim made from waste coal fly ash and recycled polymers. I installed Zip sheathing on the top of the 2nd floor ceiling joists, creating a super tight building envelope which stays comfortable with minimal heating and cooling.
Credit: Thomas Batemen Hood Architecture http://thomasbatemanhood.com/
The tight and well insulated shell allowed me to use Mitsubishi ductless mini split HVAC systems. Since there is so little heat gain or loss at the walls, I didn’t need ducts running to every room. Ductless mini splits are about the most energy efficient systems available, typically in the range of 26-30 SEER, as opposed to code minimum 14 SEER equipment.
The tight envelope requires ventilation to keep the indoor healthy and fresh. I installed a Broan Energy Recovery Ventilator (ERV) which brings in outside air on a regular schedule, which is tempered by transferring energy from the heated or cooled indoor air, saving energy in the process. Panasonic bath vent fans remove excess moisture almost silently. All interior materials and finishes are low VOC and have no added urea formaldehyde, helping create a healthy indoor environment.
The plumbing system was designed to get hot water to each fixture within 20 seconds without the use of pumps. This was accomplished by using a centrally located water heater combined with short runs of ½” pipe to each fixture. All lighting in the house is LED, all appliances are ENERGY STAR labeled, and I installed Haiku ceiling fans in most rooms to keep us comfortable while reducing the use of air conditioning. There is a carport which keeps any toxic fumes from entering the house, and it is equipped with a charging station for our electric and hybrid cars.
Landscaping is all native and drought tolerant and the driveways are a combination of pervious concrete and pavers, allowing rainwater to percolate into the ground instead of running off into streets and streams.
The house was the first project certified to the 2015 National Green Building Standard, achieving Emerald level, and also met EarthCraft and LEED for Homes Platinum certification.
The house is performing as planned – it is comfortable, quiet, and efficient. The only issue that has come up since completion is that humidity can be too high in the spring and fall when it is cool but humid out. I am planning to install a central dehumidifier for those days when we don’t need cooling without dehumidification.