Crunching the Numbers on Energy Efficiency

This fall and winter, I’ve been making some improvements around the house. I’ve gotten some new furniture, added several new houseplants, and added a handrail to the uneven front steps. The big project now is energy efficiency. 

Credit: Jonathan Cohen, Flickr. CC BY-NC 2.0

It’s a bit overwhelming to figure out which energy upgrades are the most important and most effective. It can be hard to find breakdowns of the energy, environmental, and cost impact of different choices. Companies are happy to put information about my electric bill and current home energy profile into spreadsheets and spit out energy savings numbers, but I want to see the nuts and bolts. What were their assumptions and how do different numbers or assumptions affect the output?

As I’ve tried to sort the facts from the sales pitches, I’ve found several blogs with helpful information. I’m writing about them now not just because I have energy efficiency recommendations coming out of my ears but also because it’s the beginning of the year, a good time to think about the improvements we want to make in our lives. If addressing your energy consumption is one of your goals for the coming year, these blogs have some facts, figures, and tips that might help. They’re a little less obviously mathematical than most of our recommendations, but deep down, they’re full of arithmetic, statistics, and fluid dynamics.

As I started my quest for reliable energy information, in a fog of recommendations about windows, weather stripping, and insulation, I stumbled on the blog of the Energy Institute at Haas, a joint program of the Haas School of Business at Berkeley and the UC Energy Institute. It covers a lot of different topics at the intersection of the environment and economics.

Take light bulbs. Growing up, my parents were early adopters of fluorescent/CFLs, so I’ve always defaulted to getting energy-efficient bulbs. In recent years, LEDs have supplanted CFLs as the superior energy-efficient lightbulb and may be responsible for the recent slight decline in household electricity usage in the US. When I buy a lamp, I generally buy an energy-efficient lightbulb to put in it. But the previous owners of our home didn’t have the same approach. When we moved in, there were dozens of incandescents in the fixtures. As they’ve gone out, I’ve replaced them with LED bulbs, but according to this post, I should think about throwing away those perfectly functional energy hogs and replacing them all now. Well, maybe. It turns out that in the parts of the house where I use the lights the most (and therefore switching to LEDs would do the most good), the old incandescents have already burned out and been replaced. But the post has equipped me to run the numbers for the remaining bulbs and decide whether to replace them now or later.

The most expensive decision we’re looking at right now is solar. Will the unshaded part of our roof, which faces east, generate enough electricity to make it worthwhile? What are the energy and financial risks and rewards? If we go for it, should we install it while there are still federal and state tax incentives or wait a few years, assuming technology will improve? Digging into their archives for posts about solar hasn’t exactly made the decision easier. In fact, it’s probably made it more difficult by giving me even more information to consider! As a side note, I’m glad I’m not the only one who is frustrated with the way solar companies tend to present financial savings estimates.

Although I found the blog looking for answers to my own particular questions about my own particular home, the blog has articles that questions about energy policies at a much larger scale. I was particularly interested in this post about making energy improvement programs more fair and this one about whether climate change will have an overall impact of increasing or decreasing energy consumption in the US. In other words, how does the reduced cold days vs. increased hot days cage match turn out?

After finding the Haas blog so helpful, I decided to look for more energy efficiency blogs to help me answer other lingering questions. I knew I had found a keeper when I ended up on a series about building science and the laws of thermodynamics at the Energy Vanguard blog. I also consulted the Energy Auditing Blog after our home energy audit to get information about some of the products and problems our auditor had pointed out. The blogs at Green Building Advisor are good, too, though some posts are behind a paywall. I was particularly interested in the posts at Energy Vanguard and Green Building Advisor about the global warming potential of insulation itself, as we are adding some insulation to the house and would prefer to have a net positive impact on the environment.

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