Posted by: "Carol Botteron" botteron@alum.mit.edu
> If a house has forced air heat, what is involved in adding
> a central air conditioning system using the same vents and ducts?
>
> I'm looking at houses (in Massachusetts, if it matters) and many
> have forced air. Wondering how complicated & expensive central
> AC would be.
Hi Carol;
In MA, do not assume that you need AC, especially central
AC. If you do a few things to control Summer Solar gain (direct
sunlight into the house) during Summer, and you vent the house
at night, you should be able to avoid that need, and expense.
Putting your money into general energy improvements, such as
attic insulation, will reduce both cooling and heating needs.
The average July(hottest month)temperature for Boston is 73.5F
with an average nighttime low of 65.1F The rest of the state,
out in the country, is cooler than that. Open windows at night,
then close them all during the day, once the outdoors warms to
room temperature. Most importantly, think of a window with
direct sunlight shining through it, as equivalent to a big
hotplate, in your room. If you have such a window (typically
on the east or west, that gets a lot of Summer sun, and there
is not a practical way of shading it, you might consider a
reflective inner shade, perhaps mylar. If it is in a room
that you do not use during the day (even if you use the room
at night) you might cut isocyanurate insulation to cover the
glass on the inside. That can also be used to insulate such
windows in Winter.
As you look for a house, stay mindful of its potential
energy costs. Ideally, you should look for a house with most
of its windows facing south. A 15 square foot window, facing
south, will save you about $30/yr, compared to one of equal
size that is facing north (even more if the house is heated
with oil) Two otherwise identical houses (evenly distributed
windows) but one has its long walls facing north and south,
while the other has them facing east and west....the house
with the longer east and west walls, will require about 50%
more energy to keep it heated and cooled. Locate, virtually
all of the windows on the south wall, and with lots of insul-
-ation, and good Summer venting, and you can reduce the
heating and cooling to virtually zero. There are houses in
the Boston area that have 100% naturally heated and cooled
themselves for over thirty years (no heating or cooling bill,
no funace, no AC). They do it with Winter sun shining into
the house, and Summer night venting.
You should not need central air. You might do fine with
a low-cost window air conditioner. However, you also might
look into a "mini-split" system. These are small, air
conditioners, that install through the wall. Some of them,
such as the Fujitsu units, are extremely efficient, using
only about half the energy of the average units, for the
same amount of cooling(I use them for both heating and
cooling whole houses). They can be purchased online very
inexpensively. Then, hire someone to install it. However,
your first step should be, to think in terms of getting
into a house that will not need AC (and also heats itself
efficiently), rather than on buying unnecessary expensive
equipment for wasting energy and polluting the environment.
Energy efficient is not excpensive. It actually costs less.
What it mostly requires is an awareness.
-Laren Corie-
Natural Solar Building Design
and home energy consultation, since 1975
www.ThermalAttic.com
Read my Solar house design articles in:
-Energy Self-Sufficiency Newsletter-
www.rebelwolf.com/essn.html
Home base-LittleHouses YahooGroup
http://groups.yahoo.com/group/LittleHouses/
Founder-WoodGas - Power from wood
http://groups.yahoo.com/group/WoodGas
Founder-RefrigeratorAlternatives YahooGroup
http://groups.yahoo.com/group/RefrigeratorAlternatives
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