Earth berm/underground vs. passive solar

curly_kate

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DH & I are having a debate over what type of house to build on our new property. Luckily, we still have at least a year before we save the money to start building, but I figure it's good (and fun!) to start thinking about it now.

DH really wants to build an earth berm or underground house. Even with all his assurances of skylights, I feel like it still might be dark & have a lack of fresh air. Plus, I really really really really want a screened porch, and I'm not sure how you'd plop one of those on the front of an earth berm. Also, where we would have to site the house, it would be facing north, which seems like it would make it even darker, esp. in the winter.

I would like a small (1200 sf or less) passive solar house, which I think could be extremely energy efficient, given that we will be building with that idea at the front of our minds.

So for those in the know, could a small passive solar house be comparative in energy efficiency as an earth berm? I could see that the earth berm would be less, but I'm thinking the difference might not be as huge as DH thinks.
 

Farmfresh

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I used to think when we built it would be earth bermed or possibly of log construction. Then I thought about straw bale for a while. I have had a LONG time consider such things and I have decided that an extra insulated solidly stick built house with passive solar is the way to go.

I live currently in a 1920's Craftsman style 1 1/2 story bungalow with about 1300 sq feet. I have come to the conclusion that they got a LOT of things right back then. First the size is not too big nor too small. Even though it is built on a TINY lot. When we build I will be making the rooms slightly larger (wider) and changing a few details, but the house really works and breathes as it stands. It was important back then to build a house that was easy to cool and heat since there was NO air conditioners and the furnace required coal shoveling!!

The house has about two large windows in each room which allow for great air flow. We added a roof window in the 1/2 story up and now the house for the most part is convection cooled! We open windows at night and add a few window fans on the main level to pull cool breezes in. The hottest air rises out the roof window. This could be further improved upon by the addition of a cupola, like a lot of the other houses in our neighbor hood have. If we had high efficiency windows it would be even better. The big windows also mean that my house is about 90% daylight lit. Which translates into no lights on during the day. I have central air... it has not been on for three years.

My house is situated with the long sides north and south. The roof has large over hangs all the way around. It needs NO guttering. The overhang protects the windows allowing them to remain open on the north and south unless there is a driving rain. All south facing windows are larger than the north facing ones. Planning went into the overhangs as well. They shade the windows during the summer months and yet allow the sun directly into the house all winter long. My lot is again to blame since much of that direct sun is blocked by shadowing from my neighbor's house. I also get far too much summer sun from the West and East which could be remedied by planting some well placed deciduous trees if I had the yard to do that.

Just living here we have added insulation to the walls and ceiling and improved the window situation. If we had 6 inch thick insulated walls, a high R-value roof, an insulated basement (right now it is 18 inch thick stone with a thin concrete floor) a cupola with an attic fan in it and a big enough lot to make the shading happen, it would be a dream house to heat and cool.

One more modification... Currently we have a cast iron fireplace insert stove that we primarily heat with in winter ... that would be more centrally located in the house.

Just my opinions.
 

patandchickens

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The earth-berm houses I've seen photo spreads of mostly seem to use passive solar TOO... the two are really a very compatible combination, not 'either or'. (Serious passive solar is usually combined with other thermal-conservation design features anyhow, be it earth berming or hyperinsulation or bale or cob construction or what-have-you).

This does require you to have the earth-bermed house facing south; I would have major reservations about facing it N in a real-winter climate like Indiana. (North-facing does make sense in very hot areas of course)

I see no reason you couldn't have a (smallish) screen porch on an earth-bermed house if you wanted to.

I've only ever been in 1 of these type houses, and it's a kind of atypical one in that it's pretty wholly underground and is all curvy and everything-rounded with sprayed cement walls. It's odd, but by being painted white and having sufficient skylights I did not personally find it to be dark or closed-in feeling. If you have (quite reasonable!) reservations about this, though, it seems to me that whatcha should do is go VISIT some homes comparable to what your husband is proposing, and see how they actually feel to you. It seems like most people with 'alternative' type homes are usually pretty willing to show them off :)

Personally, though there's no reason this should matter to you :p, if I were building a house and could do it any way I wanted, I think that in most circumstances I would go with a strawbale house (if I could get it past the local building code guy) with passive solar features. Earth-bermed and underground houses worry me a bit because it seems like a LARGE fraction of them have, or develop, humidity and/or leak problems. I know that some of them don't, but dunno as I'd want to sink all that money and energy into it in *hopes* that mine *happened* to be one of the lucky ones.

JMHO, good luck, have fun,

Pat
 

Wifezilla

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The earth-berm houses I've seen photo spreads of mostly seem to use passive solar TOO... the two are really a very compatible combination, not 'either or'.
THAT! Earth berm and passive solar go together like peanut butter and jelly.
 

noobiechickenlady

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I doubt you would have success with passive solar & earth berming if the site has to face north.
In order to have any significant heat gain during the winter, you would need to be facing south/southeast.

Would you have to situate any building facing north or just an earth bermed home?

You would really need lots of windows & overhangs facing south, with fewer windows facing north, if any, to get a good amount of winter sun & block the summer heat.

If you can rearrange a super insulated stickframe (or earthbag/strawbale) house so that it faces south, I would go with that. And even if the entrance has to face north, the windows can face south.
 

DrakeMaiden

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Could you compromise and build half underground and half above ground?

I agree that you need most of the windows and the longest side of the house facing south if you want to do passive solar. Why does it have to be north facing?

Also, the more time you have to make this decision, the more refined your decision will be. The longer you live on the property before you build, the more you will know about your site. Good luck. :)
 

curly_kate

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The land is almost entirely flat, so the only place with a slope faces north. We could site a more traditional home facing south, or really any direction we wanted. :) I just think that with the lot as flat as it is, it would be less expensive to just pour a slab foundation than to push a lot of dirt around.

Pat - DH works with a guy who has an earth berm house, so we are going to visit at some point. I have heard about the dampness, and also have heard that radon can be an issue.

Another cost consideration - we know several people who have built homes (DH's cousin makes a living doing it), but none of them have any experience with earth berm. So we would absolutely have to hire an outside to with experience to build it, which would mean no "family discounts." :D

Thanks for the tips!
 
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