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Over the last couple years, I’ve wondered why our master bedroom was on average about 10°F cooler than the rest of the house during the winter. At first, I thought it had to do with poor insulation or that the central air registers in that bedroom were not supplying enough warm air from the furnace. Turns out cold air infiltration was the culprit and it was seeping into our bedroom from two locations.

Air infiltration is a bad thing. No matter how much insulation you have, cold air infiltration leaking into the house will cool it down considerably and quickly. In our case, we had cold air infiltration seeping into our master bedroom from two places. The first and most noticeable was through the windows. Melody Homes (now called D.R. Horton) installed the crappiest, lowest grade windows they could get their hands on when they built the house. Embarrassingly, it took me two years to realize that snow pilling up on the inside track on the window probably wasn’t normal. I figured this was probably the first thing that needed to be upgraded, not replaced. I’ve ordered 5 new very expensive windows for the room and they should be installed late February. They are made by Champion and have had very good reviews. I was also very impressed with the demonstration.

The second place the air was seeping in was less obvious. It was actually coming in from behind the baseboards located on the exterior walls (we had two of them). When I removed the baseboards, I could feel a rush of cold air whenever the wind blew. There was about a 1/2 inch space between the bottom of the wall and the sub-floor. My solution was to use the air-tight expanding foam for window and door seals and spray it in the empty space. Careful, that expanding foam is very messy and you don’t need a whole lot. It expands … a lot.

UPDATE: The windows have been installed and there is an improvement. The room is about 4 degrees warmer than it was before. I still think there is an insulation problem and I’m going to have a home energy audit performed this spring. They cost about $400 but hopefully it will help us find ways of improving our home’s efficiency.

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• Insulating Ducts

Ugh, this was not fun. I hate messing around with fiberglass insulation, especially when I’m working with it in cramped locations. For example, a crawlspace.

Once again, Melody homes did yet another crap job, this time “forgetting” to insulate the duct work for our central air furnace which happens to run through a ventilated crawlspace. The duct work spiders off into many different directions to supply heat to our house, of which about 100′ runs through our crawlspace. So, during the winter the crawlspace is the same temperature as outside; about 20°F. Whenever the furnace is off, the duct work cools off to about 20°F and takes a good 30 seconds to heat up. As a result, we get an initial “cold blow” through the registers for about 30 seconds, pumping cold air when it should be warm. Even after the ducts heat up, quite a bit of heat is being conducted from the duct work into the surrounding air which happens to be in a non-living crawlspace. This is a huge waste of energy.

So my obvious solution was to insulate the duct work, something Melody Homes should of done when the house was first built. Before you insulate your ducts though, I would strongly suggest you seal joints and holes with mastic to insure maximum efficiency. Once the mastic was applied, I tried two different methods of insulating my duct work.

I bought R-8 duct wrap which is a 2″ thick roll of fiberglass insulation surrounded by a shiny aluminum like sheet that somewhat generically fits around 6″ duct work. It comes in 5 foot lengths and is usually slipped around the ducts before they are installed. If installing the insulation after the ducts are in place, some cutting will be required. My second method was to purchase R-19 fiberglass batts at 5 foot lengths, cut them to the right size, and wrapped them around the ducts. This was a bit more work but I caught the hang of it and the installation went pretty quick. Strangely, the fiberglass batts only cost a little bit more money than the 5 foot spans of R-8 duct wrap.

In the end, it’s tough to know which insulation method worked best. I have to believe the R-19 batts offer more insulation than the R-8 duct wrap, but the question becomes, is it noticeable and worth the small extra cost? That’s tough to answer because all the runs are different lengths and have different amounts of air that pass through them. Whatever the case, the cold blow has been greatly reduced although not eliminated. Instead of it taking 30 seconds for warm air to come out of the registers, it does so in about 10 seconds. The crawlspace is also much cooler when the furnace is running than it was before, so I know that less heat is being conducted into the non-living spaces. This means more heat is making it into the parts of the house where I want it. So the effort and time to insulate the ducts was well worth it.