Saturday, November 13, 2010


Work seems to be progressing but mostly in the design space at the moment. The electrician finished up the low voltage wiring and all but one of the new 110V circuits. We have settled on a solar contractor and a rough set of specifications for the solar PV. The contractor is now working on a specific design and a bid. We have requested that the contractor have on-site at all times someone who has worked for the firm for at least one year, so we don't get burned again by an incompetent employee that was hired a few months ago. The insulation bids that were solicited by The Project Manager Who Shall Not Be Named were, as with most of the work he did, inadequate and Paul is re-soliciting based on my feedback. Our 200 amp upgrade request is in with PG&E and we are trying to find out the schedule. Projected completion is beginning of Feburary, but I believe that may stretch out depending on the solar PV installation schedule. But best of all: The Lovely Wife seems to be happy with progress!

I had a moment of concern that the extra 100 amps for our grid connect might not be enough after I found out that the on-demand hot water heater has three heating units, each of which requires 220V/40 amps. That is an enormous amount of power, 8.8 kilowatts, but applied over a very short period of time, maximum 20 minutes for a shower, so the net energy used is less, about 3 kilowatt-hours. The electric car charger only requires one 220V/40 amp circuit, but charges over a period of 6 hours. I did a rough calculation assuming a 440V/100 amp upgrade to the existing grid feed (440V/100 amps), which seems to be fine for our current set of appliances, and it should hand the on-demand water heater, electric car charger, and HRV (the HRV is peanuts, maybe 40 watts maximum).

I also did a short tour of the gutted interior looking for holes. One "feature" of older houses such as ours is the shoddy sealing of exterior penetrations. Here is an example:
The thin white line you see on the left side of the picture is a 1/4" to 1/2" gap between the dormer flashing and the building frame in the upstairs bathroom. This gap acts as a conduit for warm air to leak out of the building in winter. The fiberglass batt insulation that was in the stud bays here is completely inadequate to stop such leakage.

Gaps also occur between the interior wall space and the living space, as in this picture:
This picture was taken in the upstairs bathroom where the drywall was removed between the raised  downstairs bathroom ceiling and the upstairs bathroom wall. The gray area is the back of the drywall on the light tray above the shower and toilet compartment doors in the downstairs bathroom. The white dust is plaster from drilling when the HRV vent was installed. The thin white line at the bottom is a 1/4" gap where the contractor failed to tape the drywall. This gap now acts as a conduit for smelly air from the bulk of the house to leak into the bathroom when the bathroom ventilation is on.

Another gap has even more serious effects:
I crawled into the unfinished attic next to the southeast bedroom upstairs where the HRV is now located. This picture was taken at the far end, where the uninsulated bathroom wall terminates the space. What you are looking at in the center of the photo is a large gap under the bedroom floor where the old forced air duct plunges under the floor toward the mechanical room where the old forced air furnace was located. The whitish yellow blob is insulation on the forced air duct. To the left of the gap, the space between the unfinished attic and the floor under the upstairs bedroom (which is over the ceiling of the master bedroom downstairs) is blocked off by a floor joist. But the gap for the forced air duct is completely open, and explains why, on summer nights, the downstairs master bedroom smelled like someone's old hiking boots.  We had a pocket door installed in the master bedroom a few years ago. The interior of the pocket door is open into the wall cavity and not sealed. So on summer afternoons, when the upstairs unfinished attic is shaded and cool but the downstairs bedroom is warm, cool smelly air from the unfinished attic enters into the wall through this gap and out the pocket door enclosure.

Here's a gap that is not quite a hole:

This is between the fiberglass window frame and the wood frame of the house. There is no insulation here although the space is sealed on the outside, but this gap acts as a thermal wire, allowing warmth to escape from the house in winter.

The disturbing aspect of these last two examples is that they are in areas where we had contractors work in the 7 years since we owned the house. They are not from the original framing or from work done by previous owners. You would think that, in the 21st century, contractors would have some clue about building science and make sure that the work was up to the latest knowledge at best quality. But most contractors are clueless about how to properly insulate a building. They are still working with knowledge they gained in the 70's when they started working.

Finally, and example of the attitude toward proper insulation in the 70's when our house was built:
This picture was taken from outside the house, looking into the cavity under the tiled shelf under the living room windows. What you see here is a chunk of fiberglass insulation on the right side and the end of a chunk on the left (obscured by the wood frame). In the middle, is a huge gap, 4-6" wide, where an electrical wire runs and the drywall  is visible. It is no wonder the tiles in the living room are icy cold in winter.

The picture is a perfect example of the attitude about proper thermal sealing in California in the the 1970's. It seems to be: "oh, California is such a mild climate and gas is cheap. Let's throw in a couple pieces of insulation here and there to say we did it. No need to do a through job". We saw exactly the same kind of shoddy insulation above our kitchen ceiling when we had a sun tunnel installed a couple years ago.

This example is why I disagree with people such as Matt Golden at Recurve, who claims that there is lots of "low hanging fruit" in energy efficiency. The number of houses that have no insulation at all and can be reinsulated at relatively low cost by drilling through the drywall and injecting blown in cellulose is far exceeded by the number with shoddly installed fiberglass batt insulation like ours. Most houses with no insulation were built before 1970 and there are far fewer of those than were built between, say, 1970 and 1995 or so with shoddily installed insulation. The cost and hassle of reinsulating a house like ours using the existing building technology, as we are finding out, far exceeds what most people are willing to go  through.

No comments:

Post a Comment