Sunday, June 22, 2014

plumbing and ventilation

We have been making steady progress and I need to catch up a bit on the blog, so I'm going to do a few posts this week.  Back in May, the plumber came and installed our rough-in plumbing...cutting lots of holes in Neil's framing.  We have since passed our plumbing inspection.

While the plumber was working, Neil installed our fancy Swiss ventilation system. (with a little of my help running the ducting) Because we are building a tighter house with more insulation than code requires, our heating loads are predicted to be low. It is also important that we bring in continuous fresh air.  Instead of losing the heat in the air we exhaust, we installed a Heat Recovery Ventilator (HRV) and specifically a Zehnder ComfoAir 200. This is the most efficient residential unit available to us.  It was also recommended by the energy consultants, Imagine Energy, that we worked with a year ago.  They did an energy analysis on the building and then made specific recommendations for our heating, water heating and ventilation.  I will do a more in-depth blog post on this at a later time.

Instead of having individual exhaust fans in the bathrooms and laundry, we have exhaust registers that are connected to the HRV.  We then have supply registers in the bedrooms and living spaces.  Before we inhabit the house, we will have the Zehnder rep come to the house to balance the system. 

There were a few reasons we ended up installing the system ourselves.

1. We had a hard time finding a mechanical subcontractor that had heard of it. Most tried to sell us on multiple spot Panasonic HRVs, which would have meant more holes in our building envelope, plus they are not nearly as efficient.  But we did end up installing one of them in the apartment portion of the house since we want a completely separate system there and it's a smaller space.
2. The subs that did quote us on installing the Zehnder wanted a ridiculous amount for it.
3. We both watched an install video and realized we could do it.  Especially since we were going to use the special Zehnder ducting shown above.  Our system was designed by Zehnder America and they were very helpful in answering our many questions.

Originally we were going to install the unit in the garage, but decided to keep it in conditioned space and put it in our conditioned attic above our bedroom and bathroom.  If you look closely you can see a grey box with 2 holes which will be connected to dampers that have the supply and exhausts ducts connected to it.