|
 Because
we are not familiar with building costs in areas other than our immediate vicinity,
we do not provide cost estimates with our house plans, but we do provide some
guidance for our custom design services. We have also recently constructed a passive
solar home of our own and being familiar with the construction process in other
areas, we can pass on the following general information regarding costs that can
be applied to most of our designs.
Some passive solar plans are more complicated than ours so the costs may not
be the same, but we pride ourselves in designing within conventional construction
methods as much as possible in order to keep the costs down. Please note that
this information does not address active solar energy systems, such as solar
water heating or photovoltaic panels, as these must be addressed by professionals
in active solar design.
Be sure to look at the "complexity" column on the far right of our
house plan
list page. We rate them either "simple', "average", or "complex,"
and a very rough estimate is that each adds about 10% more than a simpler plan
of the same s.f., but only your builder can say for sure.
A sun-tempered house plan has fewer south-facing windows than regular passive
solar homes, and therefore requires no additional thermal mass in the home to
maintain comfortable indoor temperatures. Those would be homes that have the
net s.f. of south glass between 5% and 7% of the heated floor area. Our same
house
plan list mentioned above shows the % of south glass for each plan.
These homes have approximately the same number of windows as in any standard
home, but most of them are on the south. Some of our house plans are intentionally
designed this way at the owner's request. Also, it can be difficult to get a
lot of south glass in large one-story homes where the house is deep from north
to south due to the owner's requirement with views or room sizes. If you select
a house plan that has integral mass, but find that you do not want it for several
reasons, then we can modify the house to have less glass and less mass through
our Custom Changes services.
There are no extra costs associated with the sun-tempered aspects of the home.
However, there can be a few extra costs associated with the general energy efficiency
of the structure depending upon what is standard in your area. The energy penalty
averages about 10-20% over a passive solar home with more south glass.
An Example for a $300,000 s.f home: : You might spend an additional $9,000
(3% of construction costs) on cellulose insulation, caulking, better windows,
and a high-efficiency heating and cooling. A 2100 s.f. house on a 30 year mortgage
at 6%, the mortgage payment would increase by $54 per month to borrow this additional
$9,000. At $.10 per kilowatt-hour, the total energy bill might average $75 per
month for a energy conscious family of 3. The estimated monthly energy savings
might be at least $75/ month. When you subtract the $54 extra mortgage payment,
you have a positive net cash flow the first month you move in! ($75-54=$21)
and that only increases annually! (These figures can vary widely across the
country so that is why a home energy rater should work along with your builder.
Together they can assist you with detailed costs in your area.)
As a rule, an energy-efficient home will save at least 30% on your energy bill.
Sun-tempering the home can boost this savings by approximately another 30% for
a total of 60% depending upon where you live. This savings applies to cooling
as well since sun-tempered design also keeps out the sun in summer.
Our passive solar house plans are
suitable for moderate to cold climates and Canada. Passive solar homes have more
south-facing windows than sun-tempered homes, and therefore require additional
thermal mass to maintain comfortable indoor temperatures.
You would need approximately 50 s.f. extra of windows for every 1000 s.f. in
the home. (That's about 4 extra windows, and good windows will cost about $400
each, so say an extra $2/s.f. of construction costs.) You would also need approximately
300 s.f. of thermal mass on the floors or walls for each 50 s.f. of additional
windows. Adding this mass (and finished flooring of tile or brick) over a wood-framed
floor is approximately $6/s.f. to $12/s.f., which averages another $2-4 per
square foot of total heated area.
This is where slab-on-grade foundations can help with
construction costs, since the mass and floor are one, and therefore there are no
additional costs. There are construction methods that allow for slab-on-grade
construction even in very cold climates.
The extra construction costs for the passive solar features (extra windows
and thermal mass) would be approximately $4-7/s.f. or 3-5%. When you add the
general energy efficiency upgrade mentioned above under the sun-tempered home,
the total costs for energy efficiency and passive solar construction would be
6-8%. Your energy savings with the passive solar version can be expected to
increase at least another 10% over the sun-tempered version. A 10% savings in
colder climates will save more energy than a 10% savings in milder climates.
On average throughout the U.S., a sun-tempered or passive solar home can result
in energy savings from 65-75% when combined with general energy-efficient construction.
This savings is compared to the average home being built today. The additional
construction costs associated with energy-efficient construction and our sun-tempered
or passive solar design are 3% to 8%. Perhaps add 10% as a rule. Compare this
to energy and construction costs in your area to see the benefits.
The contents of this site are copyright © 2002-2008 Sun Plans Inc.
All Rights Reserved. This material may not be reproduced or redistributed
without prior written permission. Please contact us for permission to
use or modify our designs and information. Thanks!
| 
