Our earth-sheltered house has been performing very well. Why, just the other day it did a set of cartwheels followed by some backflips. And last week, you should have heard the song it sang!
Okay, okay, so our house can’t exactly do that kind of performing. Give it a break! It’s just a bunch of concrete molded into a dome-topped cube. It’s doing its best, the kind of performance we expected out of it: it is saving energy, thereby saving us money.
I go into details in the video just below. Below the video, I have written the details in case you’d rather skim text than spend 9 or however many minutes watching a video. Also, there’s a 2020 update at the end, which might help you out further.
You’re welcome. And now, for your viewing pleasure:
The first winter: unburied
From November through most of February our first winter here, only the sides of the house were buried. What with a rat (not one of our pets! a wild one) chewing up the wires in Troy’s backhoe and his mechanic not being able to figure out the problem for the longest time, and with wet weather, Troy had to postpone his work on our house for nearly three months.
How much did we need to run the heater? Well, first you should know is that our house is 576 square feet, and the heater is only supposed to heat up to 300 square feet. That said, on cloudy days, we had to run the heater several times a day, even though we had a mild winter last year. We also often had to run the dehumidifier at the same time. We found we could get away with keeping all appliances off at night, however. Because of that, our overall energy bill was slightly lower in the earth-sheltered house that it had been in the 192 square-foot Tuff Shed the winter before, which had been equally mild.
A hot summer
This past summer was a perfect test for the performance of our earth-sheltered house, as it was a typical scorcher. We bought an air conditioner that is supposed to be for a 250 square-foot room, and put a fan in front of it to blow the cool air around. Even on the hottest days, we were able to keep the temperature inside just below eighty degrees. And we never ran the air conditioner continuously all day long. We did have some days where we ran it probably 35-45 minutes out of every hour, however.
Our electricity bill for last summer was wonderfully low, but that was only half due to the fact that we live in an earth-sheltered house. The other half was because in the Tuff Shed, we had to use a portable A/C unit. They are horribly inefficient (not to mention horribly loud), and really only cool off the space right in front of them.
This winter so far
So, our house is now fully buried, and we’ve actually had winter weather. Have we noticed a difference over last winter? Absolutely! I’m amazed at how much difference a few feet of dirt over the top has made. Temperatures well below freezing at night, no appliances running at night, and we wake up to 66 degrees inside. On cloudy days, we have to run either the space heater or the dehumidifier almost continually (alternating them), but on sunny days, even if the high is only around 40, the inside temperature will eventually climb to around 72 and hang out there with no help from any appliance.
I give it a 10
Keep in mind that an earth-sheltered house three times this size would have much more thermal mass and, in our climate, might not require anything beyond a dehumidifier (in other words, no heater or A/C). Also keep in mind that if we lived in North Dakota or Pennsylvania, we would likely have to run the heater at night, and even on sunny days.
Of course, it’s pretty clumsy when it tries to Zumba. And it’s terrible on the balance beam. But, all that notwithstanding, I give our house a perfect score. It’s performing exactly the way it ought to. Keep up the good work, house! 🙂
Update in August of 2020; BUYER BEWARE!
Each year, the temperature has stayed a bit cooler in the summer, and a bit warmer in the winter. Meaning, we don’t run the A/C unit and space heater quite as much as we used to.
Also, we run the dehumidifier less.
Note this, however: When you live in an earth-sheltered house, you have to keep the humidity down in order for mold not to grow on the concrete walls inside. Because we live in an area where the annual average humidity is over 70%, we still have to run the dehumidifier or air conditioner a lot. This would be true even if our house were not so small.
Buyer beware: therefore, you won’t save nearly as much on your energy bills if you live in an earth-sheltered house in a humid climate, compared to living in your typical wood-based home. And, you have to deal with a lot more machine noise than you might otherwise, especially in the winter. This has made me dial back my satisfaction with the house to more of a six or seven.
That being said…
Because of the small size of the house, we’ll never be able to go without climate-control appliances. However, it seems to be true, that when you combine dirt and concrete to create thermal mass for a home, after a few years there’s less volatility of the inside climate.