Posted by Shane McLaughlin
on 09/03/2013 at 3:53 PM
I've been doing a few posts
about my usage data, and decided to take a look at the bigger picture for this week's usage blog. I bought a house last summer that was 25 years newer than my previous home, but also about 30% larger. This begged the question for me: how much more efficient are homes being built today compared to older homes?
To find the answer, I grouped homes by decade built. To account for the fact that homes are getting bigger, I'm looking at usage per square foot. Here's a quick snapshot of that "bigger homes" trend. This may not represent Houston real estate as a whole because it's only TrueCost customers who volunteered their home information and use our meter data import feature.
On this next chart, you can see the usage per square foot is much lower for newer homes. This is data from August 30, 2013:
While air conditioner efficiency is a big portion of it (see the gap between the decades get wider during the summer), homes from the 2000s use less electricity per square foot all year long, especially the ones built this decade. Here's how that relationship has looked during all of 2013:
Since TrueCost is all about taking abstract data about kWh (.01 kWh/sqft/day in efficiency gains doesn't sound like much) and converting into dollars to help you make informed decisions, here you go: per square foot, new homes are using about 35% less electricity than homes built before 2000. For a typical 2,500 square foot home, at current prices (I used 9 cents/kWh for the calculation), that's 775 kWh avoided, which saves $70 off of an August electric bill.
If you're wondering about the big drop in usage during the week of July 14, that's not an error. See the explanation here