When searching for properties to build our house, one of the primary requirements was a clear south facing view. We didn't know what the house would look like, but we knew it would need the sun. Planning for our home began in 2008 shortly after we purchased 50 wooded acres near Cambridge, NY. We explored several options to heat the home in the winter, lots of mass for passive solar, masonry stove, hydronic radiant floor, and geo-thermal. But the more we researched the more we discovered the virtues and cost savings of super-insulated, super-tight houses. These houses need little heat in the winter and make excellent use of the sun.
We soon settled on a compact 1,200 sf two story design with a walkout basement. We hired DEAP Energy Group in Massachusetts to help us fine tune the details and perform the energy calculations using the Passive House spreadsheet, known as PHPP.
The design called for 12 inch thick walls filled with dense packed cellulose for an insulating value of R-44. The basement walls are insulted to R-42 with a combination of foam and dense pack cellulose. The basement slab sits on top of 6 inches of foam, R-30. The ceiling is filled with 24 inches of loose blown cellulose, R-75. We purchased Accurate Dorwin windows to get higher SHGC values to let more sun in throughout the winter. Our maximum heating load was estimated to be 12.2 kBTU/hr, small enough for a single air source heat pump on the first floor.
We pitched the roof at 45 degrees, close to the angle of our latitude, for optimal year round solar gain for the solar panels. DEAP estimated that a 6 kW array would fit nicely on our roof and get us to net zero. We installed a 6.9 kW array hoping to purchase a plug-in hybrid car in the future.
We installed an energy recovery ventilator (ERV) because the house is sealed very tight. The blower door test result was 131 cubic feet per minute or 0.46 air changes per hour (ACH). Most homes are in the 4 to 12 ACH range. The ERV allows us to get fresh air without losing heat in the winter.
Construction began in March 2010. We used local craftspersons and did much of the work ourselves. Trees felled at the site were milled and used to build our stairs and future furniture. A 1000 gallon cistern sits beneath our porch. We used low or no VOC paint and stain throughout the house. We used natural wood siding and flooring and a metal roof that maintained properly will last several lifetimes. All appliances are EnergyStar and all lighting is CF or LED.
We moved in January 1st, 2012. The house has performed well thus far. We installed an eMonitor to record our energy generation and usage on each circuit. We installed devices to record inside and outside temperature and humidity data. Meters were installed to record our cold and hot water usage. We have been posting this data monthly on our blog which also details the entire design and build of our home. Check out our blog (uphillhouse.wordpress.com) and please visit us October 13th for the Green Building Open House Tour.
Larry & Jill
Larry and Jill Burks can be reached by commenting on this blog or through member email.