|House number 18 is two stories tall with a loft space, but you would not know this as you approach the front door under the hexagon roof. It appears to be less than one story, low to the ground, like a mushroom. The roof was in fact designed with this imagery in mind. But when you enter, a generous space with many south facing windows opens to a grand view of the river and valley below (first photograph). By using earth-bearming on the north side, the owners were able to put in a lot of windows toward the sun and views. For it's size, it does not take much energy to operate. In hot weather the first floor that is surrounded by earth is delightfully cool. It's walls are earth-bermed and stick framed, with rock facing. The house is partially built into a hillside with earth-berming extending up several feet on the northern walls to the second story. The rocks for the facing were gathered from the Liberty Bell mountain pass area (check first for a permit, if required). Gathering local rocks used for wall facing, keeps the embodied energy low, only cost the labor to retrieve, and will never require maintenance.
There is only one structural wall (cement block and masonry) in the interior of the house that supports six laminated beams, holding the roof. The walls in contact with the earth are one foot thick reinforced concrete (rebar for strength) and have added spray foam. The foam prevents moisture from entering the wall, and adds insulation. Walls that are not in earth contact are stick framed with fiberglass insulation. Above the tongue and groove ceiling is a dead air space, then fiberglass batting fills the rafters. In winter, the snow stays on the roof and provides extra energy saving insulation.
A Ruegg fireplace/wood burning furnace is used for heating. The Ruegg takes in and heats cool indoor air through a series of steel tubes that pass around the combustion chamber and flue. The heated air is then channeled though vents to other areas of the house like a conventional forced air furnace (except that the heated air moves by convectionno blower is used). Air that is used in the combustion chamber itself, is brought in from outside by a separate tube so that no warm indoor air is wasted in burning the wood. The owners stated that the flue gases coming out of the chimney are only slightly warm, a good measure of the amount of heat extraction. The fireplace facade rotates out for easy cleaning. A side benefit is that the occupants can easily see the fire burn like an ordinary "recreational" fireplace; masonry fireplaces (aka: Russian fireplaces) are typically designed for small very high temperature fires; creating a large fire in one can cause problems. Also, masonry fireplaces heat primarily by radiation, the Ruegg heats by convection. Note: Ruegg fireplaces/furnaces are expensive.
Another interesting feature is the use of external bamboo shades for the windows on the south and west sides of the house, which block much of the light but still allow lovely, soft views through the spaces between the bamboo strips. For cooling, blocking light before it gets into the house is more efficient than dealing with it after it enters. The heat absorbed by the shades radiates over time into the room. There is a retaining system to keep the shades from being blown off by the wind shown in the picture to the left.
Build smaller for a cozy winter atmosphere and energy savings. Then you could build "cowboy porches" and screened porches for less money and the enhanced ability to enjoy outside living. A "cowboy porch" is a large roof overhang that one can take shelter under.