Air is a wonderful thing. I bought my dream house a couple years ago, a supposedly passive solar earth berm house, built into the south slope of a hill in southwestern Wisconsin.
First, passive solar isn’t. It needs to be so well engineered, and even then you likely need active systems to transfer heat from the storage medium (eg fans and ducts blowing over a rock bed). My house has huge windows, but the sun shines on normal drywall and the wood floor of the upper level. And of course it’s still cool in late spring when the sun stops contributing much gain and it’s still hot in late July when it starts creeping through the windows again.
Second, it’s damp. Humidity spikes like hell in the summer. I have to run a dehumidifier to keep things below 60%, and I have no idea what I’d have to do to get things below 50%. All three levels are bermed, with a cinder block wall. With the west-east orientation, we can get some halfway decent ventilation on the upper level, but we aren’t high enough up the hill to be assured of a steady breeze (we’re down in the hollow), maybe 20 or 30 feet in elevation above our creek that mercifully drains heavy rains away.
With a normal house above ground, things can dry out from the outside and, especially, you can open enough windows and catch a breeze to air the house out. It is just a far more robust way to go. At a minimum I am going to need to redo the attic insulation, seal all the ceiling joints, and put in an ERV to provide greater ventilation and dehumidification, not to mention new AC/heat pump minisplits. I also think I may need to partially excavate the berm and throw in a proper French drain, and I’m worried that I should just do a full excavation of the back, two levels down, in order to apply proper sealing on the exterior, and perhaps throw some drains under the slab.
With building science today, you can build a frame house tight enough, a “pretty good house,” stick some solar panels on it, and use far less energy while maintaining comfort, and it doesn’t take nearly the engineering and careful building that a bermed or underground house does.
I love my little hobbit hole with the big windows. I’m fortunate to be a software engineer with good enough prospects and investments to be able to afford a minor folly on a second/eventual retirement home. I wouldn’t recommend it for someone trying to build equity with their primary home.
First, passive solar isn’t. It needs to be so well engineered, and even then you likely need active systems to transfer heat from the storage medium (eg fans and ducts blowing over a rock bed). My house has huge windows, but the sun shines on normal drywall and the wood floor of the upper level. And of course it’s still cool in late spring when the sun stops contributing much gain and it’s still hot in late July when it starts creeping through the windows again.
Second, it’s damp. Humidity spikes like hell in the summer. I have to run a dehumidifier to keep things below 60%, and I have no idea what I’d have to do to get things below 50%. All three levels are bermed, with a cinder block wall. With the west-east orientation, we can get some halfway decent ventilation on the upper level, but we aren’t high enough up the hill to be assured of a steady breeze (we’re down in the hollow), maybe 20 or 30 feet in elevation above our creek that mercifully drains heavy rains away.
With a normal house above ground, things can dry out from the outside and, especially, you can open enough windows and catch a breeze to air the house out. It is just a far more robust way to go. At a minimum I am going to need to redo the attic insulation, seal all the ceiling joints, and put in an ERV to provide greater ventilation and dehumidification, not to mention new AC/heat pump minisplits. I also think I may need to partially excavate the berm and throw in a proper French drain, and I’m worried that I should just do a full excavation of the back, two levels down, in order to apply proper sealing on the exterior, and perhaps throw some drains under the slab.
With building science today, you can build a frame house tight enough, a “pretty good house,” stick some solar panels on it, and use far less energy while maintaining comfort, and it doesn’t take nearly the engineering and careful building that a bermed or underground house does.
I love my little hobbit hole with the big windows. I’m fortunate to be a software engineer with good enough prospects and investments to be able to afford a minor folly on a second/eventual retirement home. I wouldn’t recommend it for someone trying to build equity with their primary home.