The Top 10 Mistakes I Made in Building a Green Home

When I wrote about the net zero energy home that Amy Musser and Matt Vande built, I was really impressed that they were willing to share the mistakes they’d made and what they would do differently if they could go back and start over. Several readers remarked on that in the comments as well. Since I’ve puffed up my chest in this space several times and written about the green home I built a decade ago, I figure it’s about time for me to come clean, too.

Below are my top 10 mistakes, in roughly ascending order of importance.

10. Rented essential tools too long before realizing I really needed to own them.

Take that scaffolding you see me standing on above. I bought those three tables after having paid rent on a similar set for about six months. I could have saved money also by buying a storage container instead of renting one for 9 months. Same thing with a compressor and nail gun and reciprocating saw. Yes, I really was naive enough to think I could build a house without owning those essential tools!

9. Thought I could save money by doing more of the work myself.

In the very early stages, I had planned to do most of the work myself,^† hiring help when I needed it. Having never built anything bigger than a bookshelf, I was clearly delusional. I did get a lot of great experience by doing so much of the work, but next time, I’ll make sure I have people who really know what they’re doing. At least I was smart enough to sub out the drywall, though!

8. Didn’t use an air gap behind the fiber-cement siding.

I didn’t know much about air gaps back then, so we just nailed the HardiePlank lap siding directly to the walls. Also, I used #15 felt for the drainage plane and should have gone with #30. The fiber-cement siding will probably do fine for a long time; it may need painting more often, though.

7. Too much duct board and flex duct, not enough duct design.

We got a zoned system with plenums and short trunk lines made of duct board. The rest of it was flex duct. We didn’t have any hot or cold spots in the house, and I think the air flow, which I didn’t measure, was probably OK, but if the system had been sized properly (see #5), we might have had some distribution problems. The HVAC contractor did the duct design by coming over one Sunday with a notepad, walking the house, and deciding how he’d lay out the duct system. I don’t think he even used a ductulator to size the ducts, instead relying on his experience and rules of thumb.

6. Installed a water system without doing enough research.

We were trying to be as green as possible when we built the house, and it wasn’t an easy choice deciding whether to spend thousands of dollars to bring county water down to the house about 700′ off the dirt road that our 66 acres were on or thousands of dollars on a well. We went with the latter, then used a solar-powered pump. Rather than storing electricity to be able to pump on demand, we installed a 1500 gallon tank near the house and stored water instead. We ended up with iron bacteria in the water system and never really figured out a good retrofit solution. We went through a lot of filters.

5. Didn’t get an accurate Manual J load calculation.

I made sure that the HVAC contractor I hired did a Manual J load calculation to determine what size heating and cooling system we needed. He said we needed a 3 ton heat pump. Unfortunately, I didn’t know enough—or have enough time—to check his work and make sure it was right. A few years later, after my (now ex-) wife and I were already living in the house, I did a Manual J and found that the actual cooling load was only 1.5 to 2 tons. Lesson: Just because your contractor does a Manual J doesn’t mean that it’s correct.

4. Didn’t have our electrical plan completed before breaking ground.

If there’s one piece of advice I’d give you if you’re planning to build with structural insulated panels, it’s to have your electrical plan before getting anywhere near the point where you need it. The electrician is probably the trade most affected by SIPs, and I made the job even harder by not having this done. Fortunately, my electrician, Zot, is a friend and handled the job with great skill and patience.

3. Forgot to plan for basement insulation.

Oops. We changed from a crawl space to a basement to accommodate the composting toilet tank but didn’t think at all about insulating the basement walls. By the time I realized the mistake, we had HVAC, a composting toilet tank, electrical conduit and receptacles, and plumbing in the way. I did insulate and finish a room on the walkout side of the basement where most of the above-grade wall area was, but still, this was not smart at all.

2. Built too big a house.

The first sketch we made was about 400 square feet. Then it grew to 600, 800, 1100, 1500, and nearly 2000 square feet. At that point we added the full basement to bring it up to 3000 square feet. All those additional square feet seemed so important when we drew them in, but we realized later that we fell under the spell of the embiggening mind and just kept wanting biggerer and biggerer. (What do you mean?! Those are perfectly cromulent words!) Had we built smaller, we might have finished sooner, saved boatloads of money, been just as happy, and my ex-wife might not have had to sell the house in 2010—about the worst possible time to try to sell. An easy way to have had a house plenty large enough would have been to have the basement with only one floor above rather than two.

1. Didn’t spend nearly enough time in the design phase.

If I had it to do over again, this is the most important thing I’d do differently. If I’d spent 6 or 7 months designing instead of 4, we probably could have cut a year off of our construction time. The extra time might have solved all of the problems above and saved us a lot of money and heartache. We got ourselves into hurry-up mode because we were buying 66 acres with a construction loan and thought we needed everything to happen quickly. It didn’t. We should have paid heed to Albert Einstein, who once said, “If I had an hour to solve a problem, I’d spend 55 minutes thinking about the problem and 5 minutes thinking about solutions.”

 

After about 28 months of design and construction, we finally moved into the house in August 2003. It wasn’t a perfect house, but it was the most comfortable and efficient house I’ve ever lived in. Had I not made the mistakes above, it could have been even better. In my next one, I won’t make those mistakes; I’ll do my best to make all new mistakes instead.

 

Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia.  He has a doctorate in physics and is the author of a bestselling book on building science.  He also writes the Energy Vanguard Blog.  For more updates, you can follow Allison on LinkedIn and subscribe to Energy Vanguard’s weekly newsletter and YouTube channel.

 

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Footnote

† I have a history of thinking this way. In 1983, right after graduating from college, I bought a book called Backcountry Bikepacking and starting planning a solo bike trip. My imagination ran away with me, and soon my route had me riding from Shreveport, Louisiana to western Pennsylvania, then across the top of the Great Lakes, and finally down to St. Louis…just in time to start grad school at Washington University two and a half months later. By the time the trip started, I’d pared it down to a relatively modest 630 miles from Shreveport straight to St. Louis. The saner trip took 12 days of riding.