The Green Dream Group Blog

Part II:  The Attic

Attics are often very confused spaces.  Many attics were built to be outside the building envelope, but over time, inhabitants decided to extend their living space into the attic, to store stuff up there, or simply failed to install a thoroughly weather-stripped and insulated attic hatch.  Remember that since heated air rises, attics are one of the most important areas of your home to address in terms of energy savings.  (Check our Home Improvement Calculator for details!)

During the blower door test, we do zonal pressure testing on every room or area in the house to see how well connected it is to outside.  The hope is that everything inside the house is basically cut off from the outside, which should be reflected by similar pressures during the test.  Numbers range from 0 pascals (inside) to 50 pascals (outisde) - and attics usually register between 25 and 35 pascals.  What these numbers show is that most attic spaces are actually better connected to outside than they are to inside.  Unfortunately, an attic in that range still communicates well enough with your conditioned spaces to allow plenty of heat to escape, which does nothing good for your energy bills.

So, how can you start to clear up this confusion about whether your attic is an indoor or an outdoor space?  For starters, take a trip up there and look around.  Look, in particular, for insulation.  If there’s insulation at the floor level, the attic was intended to be outside.  If insulation is on the rafters, the attic is probably more a part of the conditioned space in your home.

Once you’ve figured out whether the attic was intended to be inside or outside by its builders, look at how you use it (or how you don’t use it).  The key point here is that the way you use your attic should match the way it was built.  For example, if you never go up into the attic at all, but the insulation up there is at ceiling level, you’re heating all that space to no purpose.  On the other hand, if you use your attic as storage and the insulation is at floor level, you should know that whatever you’re storing up there is effectively outside.

Especially important: make sure your attic access is well-sealed and insulated!!  If your attic is insulated to R-38 (per the Chicago code) across 99% of its area, and the attic hatch (1%) is uninsulated, the R-value for the entire assembly drops from R-38 to R-28! Payback on air-sealing and insulating the attic access in that situation would be under a month, especially in our fast-approaching Chicago winter!  If that sounds good to you, head out to Home Depot to get some supplies, hole up with our DIY weatherization videos, or get a contractor from our Affiliate List to help you out.

This entry was posted on Thursday, November 12th, 2009 at 6:02 pm by Laura and is filed under General Topics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.