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Jan 11, 2013

This Old House: What happens when an RMI staffer tries to make her century-old home more energy efficient?

 

I have a confession. I’ve been an energy and sustainability architect for many years, I work at one of the most innovative non-profit energy think tanks in the world, and my 100-year-old house consumes one and a half times the energy of an average house of similar size … or rather, it did. Last month, I participated in the Denver Energy Challenge and weatherized my little 1,800-square-foot house, hoping to reduce my energy costs from $2,100 per year to $1,500.

This time last year, I declared 2012 to be the Year of Repair. I set out to fix all the broken things in my life that still held value for me. I had a beautiful Mexican cheese dish re-polished after a tragic encounter with a dishwasher years ago. I mended two favorite cashmere sweaters that served as a moth picnic at some point last summer. Fixing my lovely but leaky house would be a gratifying finale to the Year of Repair.

I started with a home energy audit, blower door test, and infrared photography from my local utility, Xcel Energy. Okay, I actually did this two years ago. So why did it take me so long to act on it? I have the same issue that most people have—money. My planet-saving job comes with a non-profit salary, and that was a real hurdle for me when I wanted to walk my talk. In a 2012 ACEEE study, the most common reason homeowners give for delaying energy efficiency projects is expense. My energy audit was heavily subsidized and offered at very low cost. That helped get me started, but it took the Denver Energy Challenge for me to finally take action.

The Denver Energy Challenge emerged out of ARRA funding and added significantly to existing utility incentives, while also providing low-interest energy efficiency loans. Xcel, meanwhile, has an effective rebate program through Home Performance with Energy Star that I knew about but didn’t fully understand. I work in commercial buildings; this was totally different for me. I signed up and got started. I received three estimates for work from a pre-screened network of service providers and chose Precision Home Performance.

Because of costs, I had to keep this simple and hit the big problems first. My house was extremely leaky. A blower door test indicated that 90 percent of the air in the house was exchanged every hour, and I don’t even have central air. (A good tight home should come in at about 35 percent.) This was coming in through basement penetrations, deteriorated weatherstripping, new yet poorly installed windows, and construction joints that had never seen a bead of caulk or foam. (I could have told the inspector I had leaky doors without the test, since my urban chickens congregated by my back door, where a constant flow of warm air kept my hens comfortable on cold winter days.) I gave Precision the go-ahead to seal up everything they could reach. It cost me $1,850.

The ancient boiler for the warm, wonderful hydronic heating system is likely 100 years old, though I don’t know for sure. It has never let me down but is terribly inefficient and clearly on its last legs. It failed the CAZ test for carbon monoxide, and although venting is adequate and I have a CO detector, this still freaks me out. Replacing it and bringing the system up to code will cost $10,000–$16,000. Despite a “generous” $160 rebate from Xcel for a new energy-efficient boiler, that’s something I just cannot do right now.

Another issue is insulation. My house has uninsulated brick walls on the first floor over uninsulated crawl space, and wood frame construction upstairs. The upstairs was first finished in 1971 as a groovy waterbed loft, with minimum insulation, if any. I remodeled parts of it eight years ago and added R-30 to the attic, which when audited came closer to R-24. The solid brick actually works as a nice thermal mass on the south, and I do feel the benefit of that. I can insulate the inside of the crawl space easily, but as a long-time historic preservation architect, I did not want to add insulation to the outside wall of my lovely brick home. A product called RetroFoam, ideal for improving under-insulated cavities, offered promise and I looked into it for the wood-framed walls and sloped ceilings upstairs. It would have brought those surface areas up to R-20 at least. Alas, it also would have added another $1,300 to my project, and so it’s on my wish list for a future project. I settled for adding cellulose insulation to the accessible attic spaces (only about one third of the attic area) to reach R-50, and it would cost me $700.

My old house still has original windows on the first floor and in the front dormer upstairs. They are beautiful, with lead weight counter-balances that allow one-handed operation and oak frames that you would pay dearly to replace in kind. I have wood storm windows on the outside that were added in the mid-20th century. Upstairs I have eight-year-old, double-glazed, low-e, insulated Kolbe & Kolbe windows. During our energy audit, infrared photography showed the new windows far more leaky than the old ones. I can hear outside conversations through one of the upstairs windows and see a thin strip of daylight along the frame, so I called Kolbe & Kolbe to fulfill the promise of their warrantee. I can rant for an hour on the American window industry, but do check out my colleague James Brew’s blog on the sad state of window technology in the U.S.

While I waited on Kolbe & Kolbe’s warrantee, I called my local window-tinting guys, Scottish Window Tinting, to explore options for window film on historic units. Window film has come a long way, and it’s a great retrofit product. I particularly like Vista Film’s Enerlogic, but based on cost, settled for Vista’s standard spectrally selective VS61 film instead, although both are still cutting edge when it comes to window film. They are both clear (very important to me) and reduce heat gain dramatically better than a plain low-e film. I installed it on the east and west windows only, as Colorado summers are becoming more intense, and my house cooks during those hot morning and evenings. The south-facing windows are an important part of my winter solar heat gain strategy and do not suffer direct sun in the summer. The film cost $605 installed.

If you’re doing the math, I’ve now committed to a $3,155 investment in home energy efficiency; however, Home Performance with Energy Star rebates will provide $550, making the total investment $2,605. Remember that enery efficiency financing I mentioned earlier? Elevations Credit Union gave me a 3.125 percent interest rate for my loan, with monthly payments just a bit more than my anticipated energy savings, and a four-year simple payback.

The work was completed three weeks ago, and I am already enjoying a more comfortable home. It is noticably warmer, the drafts are less obvious, and I can’t wait for summer to test our window heat gain. There’s still more progress to make; in the meantime, I’ve taken my house from “absolutely awful” to “better than many its age.” I’ll know in a year if I hit the performance goals I’m aiming for, but right now, everyone except the chickens is very pleased with the improvements.

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Showing 1-5 of 5 comments

January 17, 2013

Great insights Elaine! Glad to hear the upgrades are producing noticeable thermal comfort benefits already, and it'll be great to see the real-world performance data in the years to come.


January 17, 2013

Great insights Elaine! Glad to hear the upgrades are producing noticeable thermal comfort benefits already, and it'll be great to see the real-world performance data in the years to come.


January 17, 2013

Congratulations on your project. Old houses are tough and decisions are complex.
I would suggest that you revisit using RetroFoam. It appears to be a Formaldahyde based product although that fact isn't mentioned in the product lit. These foams are very effective in difficult situations, but the quality and out-gassing vary tremendously depending on the applicator.
I would suggest dense packed cellulose or fiberglass for existing walls.


January 19, 2013

I would recommend a Navien Condensing Water Heater for your hydronic replacement.
The have a 199K BTU capacity and cost around $1400 for the unit. It could easily replace both your water heater and your boiler. At 98% efficient it can make a big difference in your gas bill.
http://www.navienamerica.com/
I am sure it will cost more than the unit to install and connect to everything but it should be much cheaper then 10K.


January 25, 2013

I think your story shows the need for in-depth home energy audits - beyond the simple audit you received from your utility. The fact that you waited two years to make any improvement shows that it was ineffective. Energy auditors need to provide homeowners with detailed, accurate savings estimates of various improvements so they can *confidently* make the improvements that make sense.

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