Hurley-Kawahara
SANTA CRUZ GREEN BUILDERS / RESIDENTIAL
This is a very special house. A whole house retrofit, it was our first certified Passive House, and the first to be completed in Santa Cruz County.
Passive House is a German certification that sets extremely low energy consumption requirements. Once the house is finished, you have to live in it for a year before you can get certified, to make sure the computer modeling actually hits the targets with the occupants living in the home.
The main components of Passive House are super air sealing (which gets tested with a device called a blower door), super insulating (we are talking 8″ thick walls), energy efficient lighting and appliances, and a device called a heat recovery ventilator (HRV) that constantly brings in fresh air and exhausts stale air, but does this transfer in a way that very little heat is lost in the process.
What makes this project even more unique is that it is one of only a few Passive House retrofits in the country. Most Passive Houses are built new. It is much more difficult to hit the air sealing numbers required when the old framing stays intact. But we were able to hit all the numbers and complete the project with a lot of diligence and hard work. With a house like this, the numbers speak for themselves. We scored .59ACH on the blower door test at 50 pascals. And in the years the owners have lived in their new home, energy use has dropped by 80%! That is a huge amount of savings, especially when you consider this over the life of the house.
The house also features a rainwater catchment system that feeds the clothes washer and toilets, gray water diverter from the clothes washer to landscaping, solar hot water for domestic use and also for heating the home.
This old house, built in 1922, is an example for all the old houses in the country. Every old house could be updated without being torn down, and they too could use 80% less energy. Imagine what that would do for our energy bills and global emissions…
It was a great project and we invite anyone interested to check out the owners blog, since she has put a huge amount of time and energy to write up the whole experience, including her research and conclusions.
If you are interested in a Passive House, check out Graham Irwin, who did all the passive house modeling.
Features
All LED Lighting
Energy Star Appliances
Heat Recovery Ventilator
Passive House
Rainwater Catchment
Reclaimed Materials
Retrofit of 1922 Craftsman
Solar Hot Water
Super Air Sealed
Super Insulation
Triple Paned Windows