Thursday, February 24, 2011: Updated Sunday April 14, 2013

Air Sealing

Getting solar panels will reduce/remove your electric bill but they won't make your house any more energy efficient. They won't do a thing for the gas bill either.  Or the kids Orthodontia.  

I recently had an energy audit from a company called "Green Label Solutions".  

They came over on a Friday morning and for 2 hours took thermal images of my entire home.

They measured everything from the flame in my gas furnace to the ice cubes in my freezer.

They suggested I have the following things done to my house:

  • Seal all the air leaks around my windows and doors.
  • Put foam pads behind all exterior wall plates.
  • Put in more baffles for my soffit vents in the attic.

I was kind of on the fence with having these things performed until a few weeks ago when the outside temperature got down to 2 degrees F. Our house was not cold but I could feel drafts coming from our windows. Specifically the crack between the vinyl window casing and the wall itself.

Why don't home builders spend an extra $2 per windows and install them correctly? Insulate and air seal please. Also, why put in an energy star vinyl basement window only to have them set into a steel frame? That defeats the whole reason for having a vinyl casement in the first place. Now I have Energy Star windows being nulled out by thermally conductive casings.

There is nothing I can do about my 7 basement windows without first removing them and re-doing the entire install. What a pain.

While I'm on the topic, I have a gripe about Energy Star Windows. In order to qualify for energy star, they must be able to leak less than 0.3 cubic feet of air per minute. This spec is like an ice cream shop advertising that their milk shakes are guaranteed to contain less than 0.3 cups of poop per serving.

It is beyond me why they continue to produce such windows and call them energy star. Give me one that carries a zero cubic feet/min leakage rate please!

Update 3/12/2012:  It has been over 1 year since I had  Green Label Solutions come out and air-seal my home.  I went back and compared my last 3 months worth of natural gas bills to the same 3 months the year before.  

 Natural Gas 2011 Season2012 Season% changeSavings $ 
 December 14.2 12.2 14.08% $19.89
 January 19.2 15.6 18.75% $34.41
 February 14.0 11.7 16.43% $17.64
 3 Month Total 47.4 dtherm 39.5 dtherm 16.42% $71.94

Not only were there significant savings on my gas bill, my electric bill went down too, especially in the summer time when the Central AC is running.  
The following chart shows my electric usage (not my net usage as my solar panels offset nearly all consumption) the season before and after air-sealing my house.  

 Electricity2010 Season2011 Season% ChangeSavings $ 
 June 90362630.68%$27.70
 July 13821293 6.44% $8.90 
 August2197 1040 52.66 $115.70 
 September1397 825 40.94% $57.20 
 October1126 952 15.45% $17.40 
 5 Month Total 6102 KW-Hr4110 KW-Hr28.88% $199.20 

July of 2011 was unseasonably hot and humid.  I assume this is why the savings were not as significant that month.  In 2011, I installed a ceiling fan in the living room and added a misting system 
to the Central AC. These additional improvements in efficiency skew the data a bit.  I assume that air-sealing alone contributes to an 18-20% efficiency improvement while the other improvements make up the rest.  

The additional shading cast by the solar panels on my roof reduce the home's air conditioning needs by an estimated 5%.