2015 Challenge Participant:
Weedon Built - Shimizu Residence
Applicants: Lynita Shimizu, Charlie Weedon
Project Address: 210 Hillside Road, Ashford, CT 06278
Bdrms./Sq. Footage: 3 BD - 2478 sq ft
General Project Overview:
The house was built by Weedon Built LLC, a company whose heart embraces thoughtful and practical Passive House building. The design was a collaboration between Charlie Weedon and homeowner, Lynita Shimizu. Our main goal was to build a durable, energy-efficient, healthy home which would include an art studio and support an active retirement life. We were fortunate to purchase a 44-acre property featuring a field (southern-facing slope), a pond, and woods abutting 7,800 acres of Yale forest. Our desire was to minimize construction impact to this beautiful property while maximizing energy efficiency.
The 2,478 sq-ft house is all-electric and ready for electric car charging.
Total electric consumption from Jan to Nov 2015 was 6,185Kwh and production was 10,930Kwh. The net electric consumption for the year from 12/9/2014 to 12/9/2015 was minus 4683 Kwh. This would be equivalent to a HERS index of -22.
Low consumption is the result of using highly efficient Energy Star appliances, LED lighting, tight insulation, and a small, single unit Heat Pump.
The air quality is maintained via a heat exchange system which replaces air from the bathrooms and supplies fresh air without losing heat.
One focus of the design work was how to maximize the merit of southern exposure hillside. To nestle the home into the slope and make it part of the terrain, the first floor’s north side is partially bermed and features a split-level entry. The southern side of the house has triple-paned windows over-looking the pond and forest beyond. The roof overhang is such that the sun does not enter the rooms in mid-summer and reaches deep into the space in mid-winter. Windows can be open on sunny, below-freezing days.
The house is extremely comfortable with indoor temperatures in the low 70’s in all seasons. Although there is only one mini split heat pump (in the stairway) all rooms remain within 2 degrees of each other. The ceiling fan installed to equalize room temperatures has been used very little.
The house was built with thick aluminum roofing and fiber cement siding, protecting it from weather elements, simplifying maintenance, and improving the durability of the house.
LED lighting throughout the entire home.
Orientation and Envelope (Windows, Insulation, Framing):
Walls: Double stud 2x4; 14” thick dense pack cellulose
Foundation Walls: 2" ureathane foam board & 6" dpc
Flat Ceiling: R-90 Blown Cellulose
Vaulted Ceiling: R-91 Dense Pack Cellulose
Slab: 6" of EPS with 4" around the perimeter; Stainless steel screen, and acoustic sealant were used to prevent insect invasion.
Windows: Intus PVC triple pane
Heating, Cooling, and Hot Water:
- Mitsubishi air-to-air heat pump to provide heating and cooling. One-ton was all that was needed to provide heating and cooling at an efficiency of 10.5 HSPF and 23 SEER.
- One 50-gallon marathon heater is used for hot water. The water heater uses the output of approximately 6 PV panels. The net cost of the heater and 6 panels was roughly $3,500, which (at this price) gets a long life system with no annual cost.
- Hot water is supplied to low-flow fixtures which use 3/8" pex to save energy and provide quick response times.
- Fresh Air Ventilation: Fresh air is provided via a UltimateAir 200DX energy recovery ventilator
- Whole House Ventilation: A 30" fan was installed in the attic to cool the house on summer evenings. An ins
- All LED lighting throughout the home.
- 7.7 kW of photovoltaics mounted at a 30 degree angle directly mounted to both the house and the rough.
- Total of 39 panels installed with 32 on the home, and 7 on the detached garage.