A Solarium Entry for a
Passive Solar Home
A passive solar home needs
sun and an air-lock entrance. A greenhouse design can combine
when builder Rich Davis was designing a new home for himself and his
wife Beth Zaring, he didnít think of it as a passive solar design. He
was planning to heat the new house with a wood furnace and just wanted
less work at cutting and splitting logs. He researched energy efficient
design and air tight home details. But, he also got some inspiration
from Bruce Andersonís Solar Home Book.
Entry - Davis Home, Jackson County, OH
square home that he built is a marvel of efficiency and a model of what
we can do to save energy in our own home designs. Rich and Beth burn
just one or two cords of wood each year. That translates to about a
quarter of the energy used by most homes of that same size and in a
similar climate. Wouldnít you like to save 75% on your heating bill?
Sure, youíd be saving the planet too, but wouldnít you like to save 75%
on your heating bill? And, most of the details that keep the house warm
in winter also cut cooling cost in summer.
Rich did it. He created an efficient layout: a slightly off-square plan
with the longer side facing south, and a stack of three floors. The
lowest level is half into a hill, and the upper level is nestled under
the roof. He insulated the concrete lower level walls with 4″ rigid foam
on the outside surfaces. Exposed areas of foam were protected with a
cement stucco finish. Another 1″ of foam insulation was placed below the
floor slab. He built 12″ thick walls (two 2x4 walls with a 4″ air space
between them) and used 2x12 roof rafters. He stuffed the walls and roof
with insulation. Rich paid careful attention to caulking and making sure
that the homeís envelope was air tight. He ducted fresh outside air to
his wood furnace so that it wouldnít draw cold air across living spaces
from windows and doors.
interesting part of Beth and Richís home, and the only component that
really supplies solar heat, is the room that they call the Greenhouse.
It serves a variety of purposes. First, itís an air-lock entrance. There
are doors into it on the east and west ends that are the main entrances
into the house. A big sliding glass door separates the greenhouse from a
combination living/dining room. In cold weather, people enter through
the greenhouse, but cold gusts of air donít. Second, itís a mud room.
The masonry floor stands up to the mud from Bethís garden and goat farm
in the summer and snow on boots and skis in the winter. Third, it really
is a greenhouse. Beth and Rich start their seedlings there each spring.
most importantly, itís a solarium. Itís actually a comfortable sitting
room, with no extra heat but the sunís, on most winter days. The south
facing windows warm the space up enough on most days to send heat into
the main house.
As you can
see in the photo above, Rich built a deep roof overhang to shelter the
Greenhouseís windows. That blocks the rays of the sun when itís high in
the summer sky. That detail, and Venetian blinds, keep the space shady
and cooler in summer and early autumn.
So, a series
of fairly simple and low-tech details and a functional, multi-purpose
sunroom combined for great results. This isnít a theoretical design. It
works. Beth and Rich have been enjoying the benefits for over twenty
years. A similar greenhouse/entry/mud room could be added to the south
side of many homes, at a fairly reasonable cost. Itís something to think
Don Berg, Todays Plans