Wednesday, April 21, 2010

Open House

Our house is almost finished, and we will be moving in just a few weeks from now!

Before we move in, we are hosting an Open House for the community on Saturday, May 1, from 1 to 5 p.m. If you want to learn more about the technical aspects of Passive Houses, or you're just interested in seeing how our project has turned out, this will be your chance to tour the house and talk with us or with our builders, Blake and Larry Bilyeu.

The address is 1125 16th St. NE, Salem, OR 97301.

Wednesday, April 14, 2010

Handles, toilets, and other optional things

Cabinet and drawer handles went on last week.  We went with a simple, functional handle.

The half-bath downstairs is nearing completion.  The pedestal and toilet are in.  Soon we'll put in a medicine cabinet above the sink.

The toilet is of the double-flush variety, so it's got a little flush selector on top of the tank.

Our faucets even pour water into the sinks!

Around the corner in the mechanical room we have lots of activity.  Our cable TV/internet comes in and is split off.

And on the opposite wall the Power-Pipe is in!

The Power-Pipe is a drain water heat recovery device.  It recovers heat that would be sent to the sewers in our drain water.  It's entirely mechanical, with no moving parts and no maintenance needed.  It consists of two pipes - a large drain pipe in the center and a smaller pipe wound around the outside.  The contents of the pipes never touch.  The hot water from the showers upstairs drains down the center pipe.  Water traveling down a vertical pipe flows as a film down the sides of the pipe.  It doesn't just fall down the middle.  Fresh water from the city is traveling up the spiral pipe.  Because the pipes are made of copper, the heat from the drain water is easily transferred into the cool, fresh water.  This pre-warmed water goes into the hot-water heater and into the cold taps on the sinks and showers.

But we're still not done with the mechanical room.  We also have the ventilation system in here.

The black box up there is an Energy Recovery Ventilator.  This is a major component of that makes our house efficient.  It actually works a bit like the Power-Pipe.  In the winter it takes the heat from the stale, inside air and warms the cool, fresh air coming into the house.  In the summer it does the opposite, reducing the need to cool the fresh incoming air.  It is very efficient and can nearly equalize the temperatures of the incoming and outgoing air.  Since our house is so air-tight, we get to make sure that all the fresh air coming in gets pre-conditioned by the air going out.  Our little heat pump will have very little work to do to keep things comfortable.

Stepping outside we have the frames for the back steps.  We anticipate pouring concrete in the next few days.

At the front of the garage we installed the gooseneck lights that Blake made, and they look great.  Thanks again, Blake!

Thursday, April 1, 2010

That's tight

A few months ago I talked about the certification and testing process to become a Passive House.  In short, one of the biggest hurdles to clear is the air-tightness of the house.  A blower-door test must show less than 0.6 air-changes per hour at 50 Pascals pressure difference (ACH 50).  One air-change per hour means that an amount of air equivalent to the volume of your house is exchanged with outside air over the course of an hour.  All that new air must be re-conditioned, which uses a lot of energy.  0.6 ACH 50 is a very difficult level to reach -- a new house will commonly be ten times as leaky.

Last weekend, while giving a talk at the Passive House Northwest 2010 Regional Meeting, Blake announced the results of our latest blower-door test.  It's important to note that Passive House measures house volume differently than most other certifications (such as Earth Advantage).  PH does not count the inside of walls and similar areas that do not hold conditioned air, making the calculated volume smaller.  Therefore, a blower-door test will show a greater number of air changes per hour because there is less air to exchange.  We calculated numbers for both the PH method and the traditional method.

Ok -- the results.  Using the PH method, our house measures 0.26 ACH 50!  It is more than twice as tight as the standard requires.

Using traditional methods, we measure 0.23 ACH 50.  If you know other people who have tested their house for something like Earth Advantage (which requires 6.0 ACH 50), this is the number you would use to compare.

How did we get the house so tight?  Attention to detail.  Blake and Larry carefully taped all the seams in the plywood shell.  We ordered casement-style windows and doors with 5-point locks that close tightly on their seals.  Every penetration of the shell is taped or gasketed or somehow sealed.  We even ordered a special dog door that seals tightly with magnets all around its edge.

Some of you might be thinking, "Isn't that too tight?  You'll build up CO2 and radon and VOCs and stuff!"  Not to worry.  The reason we make the house airtight is so that we can carefully control how air moves in and out of the house.  We have a ventilation system that constantly provides fresh air from outside.  More than that, it takes air out of the "bad air" places (bathrooms, laundry, kitchen), and runs it through a heat exchanger that moves the heat into the fresh air that's being pulled into the house.  The fresh air is pumped into the living areas.  By recovering the heat from the air we are exhausting, we don't waste energy re-conditioning air over and over again.  And by being airtight we make sure that virtually all of the air coming in or out goes through the heat exchanger.

When combined with super insulation and plenty of solar heat gain through the windows, these features act to vastly lower the energy required to keep the house at a comfortable temperature.