saving energy

Raised-Heel Trusses

Since the late 1960s, most houses have been built with engineered trusses (click on the link for more information than you need) instead of traditional rafters. Trusses offer greater spans to open up our interiors with great rooms, require less time and labor to erect, and provides a more uniform pitch to the roof, which may not seem important to you, but your roofer loves it.

Early truss systems resembled a triangle with a bunch of triangles inside the outside one. The problem that we ran into, from an energy usage standpoint, were those skinny angles at the ends of the truss. Often, there was not sufficient room to get an adequate amount of insulation into the space. I see a fair number of homes with shadowing on the ceiling at the outside edges of the rooms from precisely this.


A 1970s Engineered Truss

Note how skinny it is at the low edge. Not much room for insulation.

When energy was really cheap (raise your hand if you can remember $.25 gasoline!), this was not a big priority. Today, with more expensive energy and an improved awareness on how to heat and cool our homes efficiently, what happens on that edge is important. One solution was to re-design the truss. Meet the raised-heel truss.

The raised-heel truss

Raised-heel trusses are engineered to provide enough space for the insulation. By design, they are taller than older truss designs at the point where they cross the wall. This section, called the heel, intersects at the perimeter wall and lifts the top chord of the truss. From my research, it looks like the energy-saving qualities of the raised-heel were not the primary reason they were developed, though. Initially, the were built to match roof lines and increase curb appeal. Go figure . . .

Even though the cost for these trusses are not substantially higher than with other truss systems, I still don’t see that many of them. When I do, it’s good news for my clients!

(A quick note on the video - I shot it in an attic while hanging from the framing - it might not sound smooth and polished.)

How Much Difference Does Insulation Make?

I did an inspection in Lewiston late last year on a very cute little bungalow near Normal Hill. The home was classic brick with trees lining the street in front. The clients were a young couple buying their first home.

One the findings that we came up with is that there was nearly no insulation. The home had an old beast of a furnace that kept the home warm - when it ran, and it definitely like to do that.

Jack asked me for some advice about how to handle this. We talked about the advantages and disadvantages of blown fiberglass and blown cellulose. One nice thing about our local Home Depot is that they will essentially lend you the equipment to insulate the home yourself if you purchase a set amount of the insulation from them. It's a pretty good deal, one that I took advantage of in my home.

Jack sent me these pictures, a before-and-after of the attic space. It's pretty impressive, though it's going to make it a lot tougher for the next inspector to traverse the attic.

Jack put in about a dozen inches of new insulation. One of the advantages of the blown cellulose that he chose is that it air seals much better than fiberglass. It's also much less expensive.

It always makes me happy when I get a chance to see my advice make a positive difference for the people that I work with. In this case, it's a young couple who just spent one afternoon and made their house much more affordable from an operating expenses perspective.

How more affordable?

Jack sent me the numbers - bear in mind that this has been a really mild winter, so the numbers are a little lower than in a cold year.

  • Month 1 - $209 for gas and electric.
  • Month 2 - $125 for gas and electric.

So, the bill dropped by 40 percent over the course of a month. Pretty darned impressive and I'm awfully happy for the family. Good job to them!