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Community and Q&A

We need some advice on a solar envelope house

Erin Litteken | Posted in Energy Efficiency and Durability on

My husband and I are considering a home on a huge lot we love, but we found out it is a solar envelope home built in 1983. I’ve read mixed reviews on this type of home and we have some concerns. We’d appreciate any help!

1. If we wanted to ever convert it to a normal home, is that possible?

2. Have people really experienced health issues stemming from mold and modes growing in the walls and under the house from the moisture in the air? How common is that? Fires seem to be a concern too.

3. This home is in southwestern Illinois. Will it really make a big difference in our bills?

4. Can we ever finish off the basement without ruining the air flow?

Thanks for any help anyone can offer. We want the place so badly but we’re afraid it’s a money pit.

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Erin,
    This type of house -- usually called a "double-envelope house" -- is a discredited design. It's hard to estimate how expensive it would be to fix such a house without a site visit.

    These homes usually have too much south-facing glazing (leading to overheating at certain times of the year, as well as lots of heat loss at night), insufficient insulation, fairly high levels of air leakage, fire safety issues (due to the lack of firestops between the walls), and possible mold and air quality issues due to crawl spaces with exposed earth.

    I wouldn't buy such a house. But it's possible that some of the home's problems have been fixed in the years since it was built.

    To read an old paper on this type of house, see "Thermal Envelope Houses". To read a more recent article, see Enertia Double-Envelope Home Still Has Problems.

  2. Jane Wheeler | | #2

    Erin:

    I bought a double envelope home four years ago. It was built in 1983 and is located in central Michigan. The basement in this house is finished, there is no crawl space. The house hasn't had a moisture problem since I have been here (we had record rains and flooding last year) and even with the frigid cold we had this winter I didn't use over a tank of propane to heat the entire house. I have found it well insulated and even with the south facing windows, it stays relatively cool. I ran the air conditioning maybe a total of 7 days last summer.

    I have found it to be a well built house and have no regrets about buying it.

  3. thur1042 | | #3

    Jane, my wife and I are considering buying a solar envelope home in Michigan. I would love to talk to you about your experience. my email is thur1042 att [email protected]

    1. GBA Editor
      Martin Holladay | | #4

      Thur,
      Just so you know -- Jane posted her comment 5 years ago. I doubt if she is still monitoring this page.

  4. thur1042 | | #5

    Martin. I saw that. You never know...

  5. thur1042 | | #6

    Martin,
    Not sure if I should start a new thread for this, but I have a few questions I would like to pose to you and the rest of the GBA community.
    I am looking at purchasing a "solar envelope" home in Michigan (very cold winters, hot and humid summers). The house doesn't have a crawl, so maybe your concern about moisture doesn't apply to this house? It is on a basement, which is poured concrete. There are airways around the perimeter of the finished basement. Also, the solarium (south facing wall) has insulated window coverings that are easy rolled up and down. Do you think that would eliminate your concerns about overheating in the summer and heat loss at night?
    The house is heated by an electrically powered radiant heater above EVERY window. I understand that supplemental heating may be needed for Michigan winters, but I would prefer natural gas (far more economical), but I am not sure if the circulating air would eliminate the benefit of the solar envelope.
    I like the house, and love the possibility that the solar envelope would reduce my energy needs. I just don't want to get into a house with moisture problems and I would prefer to not heat a house in Michigan winters with electricity (even if it is a reduced need due to the efficiency of the house).
    Any input you have would be appreciated.
    Thanks,
    Jeremy

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