Budget Solar Retrofitting

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ILLUSTRATION: KENNETH LIN
Diagram: The sun's seasonal phases.

Budget solar retrofitting ideas will help cut costs and make for more efficient energy use in your home.

We take the sun for granted as it lights, warms and
measures our lifetimes in precise 24-hour segments. This
free, high-quality light and its attendant energies can
enhance our lives by the manner in which it interfaces with
the various structures we inhabit. This light-space
relationship has reached a critical, often unrecognized
importance during the last century as most of us have moved
indoors in the workplace.

In the past the sun was taken more seriously with the best
body of “solar law” belonging to the ancient Romans. In
their cities, they carefully controlled building size and
location to enable each space to receive its maximum ration
of light and heat. In America, most farmhouses in the early
colonies were oriented with the long wall facing the sun’s
benefits. By the mid 1800s we began to forget the sun’s
benefits. The mass production of cast iron wood stoves in
Troy and Albany, NY worked so well as a heater that a
home’s position to the sun seemed virtually unimportant.
The common use of the light bulb found us further from the
need to properly employ the sun.

Today, over two decades removed from the 1970s’ energy
crisis, we are again returning to the solar knowledge our
forefathers embraced. The sun is even available to most
suburban and rural homes which may not have one wall
oriented near south. To determine the “solar window” of the
structure in question for its potential to deliver energy
to the inner spaces, check your own shadow at noon standard
time (1 P.M. if it is daylight savings time) and find solar
south to be opposite your north body shadow. If one wall or
a portion of your structure is within +/-10 degrees of
this, you have good orientation. You will have a nearly
desirable situation, however, if the wall with the most
windows is within 30 degrees of solar south (beware of
west-facing glass, as the summer sun, low in the sky from
June-Sept at 5:30 – 8:30 P.M., can lead to overheating).

How do we use this basic knowledge of your own “solar
window” to best enhance the home’ s energy efficiency?
There are a number of inexpensive budget solar retrofitting steps that one can apply
to every structure to substantially improve it’s
performance.

First: Remove the largest north-facing
window possible as it always loses energy. Most homes can
afford the loss of one or more non-sunny windows with the
wall that replaces it insulated (R12-R20) much better than
the window (R1-R4).

Second: Install a larger south-facing
window or enlarge one or more existing units. Remember, the
sun needs to “see” those windows for the majority (5-6
hours) of the day. Choose windows having modern
high-efficiency glass rated at R3R4, and in most cases they
can be non venting Axed units because the typical home
already has enough venting windows. You now have the
opportunity to receive up to 250 Btu’s per sq. ft. per hour
at midday …free. For six hours facing near south during
winter in the northern United States, the average
availability will be 175 Btu’s per sq. ft. Each 10 sq. ft.
of glass which will transmit about two-thirds of this
energy will therefore yield 700 free Btu’ s to your space
on a sunny day in addition to the daylighting benefit. The
value of this energy can be compared to one thousand watts
of electric heat, or 1 kilowatt, which for one hour yields
3414 Btu’s and costs from 10-20 cents, depending on where
you are. This does not count the fact that a window would
probably also reduce lighting electrical usage. A 100-watt
bulb burning for 10 hours also uses a kilowatt.

Third: Increase insulation values. The
concept here is to upgrade the R value (resistance to
energy flow) of various parts of your home’s outside
surfaces. The most popular type of insulation is
fiberglass, but without proper installation techniques, its
performance at mid-winter is one-half or less of the
claimed value. Evidence of this is starkly visible in all
northern locales as you observe the huge icicles and roof
ice dams. This often occurs despite fiberglass insulation
with R24 or R30 claims. You must become aware of the proper
installation methods involving an understanding of
ventilation and moisture movement in tight spaces. The
“correct job” is often hard or impossible to achieve in
retrofitting. My general advice is to use one of the foam
sheet insulations (2 feet by 8 feet – 4 feet by 8 feet etc.) purchased on the
unit pricing principle of cost per installed R value.
Generally foil faced urethanes (polyisocyanurate) or
Styrofoam are best.

One would first retrofit the north roof, paying particular
attention to making sure the roof covering (whether it is
shingle, tile, slate, or any other surface) is secure and
contains no openings to the insulation housing beneath.
Next in priority would be the northern wall(s), and final
the south roof and walls. As you proceed, replace all
windows with modern units having R values of at least 3 to
4, which usually have their perimeter cracks foamed with a
non-expanding spray foam. Remember, the most essential part
of insulating is the attendant sealing of all gaps, wires
and other penetrations with a high quality caulk.

One must at the same time insulate the portions of the
walls or foundation below the siding typically left undone
in the past. Why would you want your house to be barefoot
in winter? One should dig up the foundation as far down as
possible and install the foam insulation (at least R8-19)
with an outside-quality waterproof membrane before
backfilling. This may offer a highly recommended
opportunity to install better drainage to daylight than the
typical home received at its origination. You can complete
this foundation insulation job by covering the outside
surface from 6 inches – 8 inches below grade up to the bottom of the
siding with 3/8 inch pressure-treated plywood or other
weatherproof skirting material.

Finally, one must upgrade the basement or crawl-space and
make a serious effort to shut off ground water and, more
importantly, the invisible movement of ground moisture as
water vapor into the home. Even the best insulated modern
homes, which are reasonably insulated as required by code
on 5 sides of their “box,” fail to close themselves off
from ground moisture. The vast majority of homeowners spend
a goodly portion (5-10%) of their heating and cooling
budget trying dry out the ground under their house Mid
never succeed. You could test yowl own home during winter
conditions by placing a 10-15 square foot piece of a vapor
barrier over your concrete basement floor or crawlspace
dirt and you will observe with in a day water droplets on
its earth sick. Many methods are available to mitigate this
undesirable moisture movement. It your basement is usually
dry and crack free, you can apply one of the quality liquid
surface treatments designed waterproof the concrete. A
crawl-space can be fixed by installing a large piece of
Flatic vapor barrier everywhere, and carefully sealing all
penetrations with the edge held in place by weights such as
bricks or pressure-treated wood scraps. Older, uneven
rock-laid or degraded basements will need further, more
extensive efforts.

Fourth: The previous reasoning with
windows its solar collectors also applies toy new or
existing doors with glass placed (oil sunny exposures. That
old wooden door was a 40-60 lb. object that you slammed a
few thousand times each year and still had expectations of
it’s sealing tightly. The old saying that such doors were
so poorly scaled that “you could throw a cat through them”
is not as ridiculous as you might think. Modern doors with
urethane core insulation, steel or fiberglass facings and
the latest insulated glazing are a huge improvement over
the older wooden door. The major improvement is in their
sealing, on roughly 20 linear feet of perimeter crack with
a deformable or magnetic gasket These doors are one of your
best retrofitting buys as they reduce air leakage to a
small percentage of the average door that they replace.

Since the average structure has a large portion of its
energy losses from air movement through many unsealed
cracks and openings, we need to make a concerted effort to
tackle them. One needs to consider both in-filtration and
ex-filtration of air, both driven by the obvious causes of
the wind with attendant door and window crack leakage.
Those air leaks are in fact driven in larger part by
unrealized factors such as door operation, vent fan
operation and barometric pressure changes. Additionally,
perhaps the most common leakage is one caused by air
expanding as we heat it. During an average winter, the
interior air will need to be heated an average of 50 degrees Fahrenheit.
As the air heats, it expands, and requires that much more
prevention from escaping. Sealing of the myriad gaps beyond
that of window and door openings and their frame cracks
involves a careful examination of your home’s complete
exterior. A good place to start is the clothes-dryer vent.
Typically these vents are a perfect example of how not to
insulate an opening, with its skimpy aluminum flapper.
Purchasing a substantial plastic replacement with a
vertical outlet capped by an upside-down can would be a
tremendous start. The can is simply lifted off its pipe
during operation and closed by gravity. Other fan vents
should also be checked and improved where possible. The
last vents to check would be those that service the attic
space above your insulation, as they may well be too small
for the job. Check the latest information on venting above
insulation, and upgrade yours accordingly.

Purchase some high-quality caulk (latex, silicone or one
component urethane as appropriate) and relentlessly pursue
a crack-sealing mission. It is one of the most effective
expenditures you’ll ever make. Don’t overdo it; more isn’t
necessarily better, just be sure the caulk makes it well
into the confines of the small crack or space to be sealed.
Heating the tube in warm water to 100-110 degrees Fahrenheit often helps
its flow rate. Use an old sock with a hole in its toe to
cover the tube to keep it warm. Gaps wider than 3/16 inches –
1/4 inches should be sealed with a one-component spray foam.

Fifth: Tackle the reduction of heating and
cooling costs that are beyond the obvious tune-art, of your
mechanical equipment and major exterior gaps. A start is to
follow the common regimen used earlier in the century of
closing drapes and curtains to exclude heat or cold. More
to the point is a reduction of solar gain in summer which
can be at its peak after 2 pm through southwesterly or
western windows. Fortunately, the awning industry has
returned in most parts of our land and the outside
application of shading combined with the use of a whole
house fan getting its air from the non-sunny side, can go a
long way toward naturally cooling your space. Daily
reductions of 8-10 degrees Fahrenheit are easily possible with just this
method. A large maple tree planted in the appropriate
western space can be nearly as effective. It is best to
manage energy gains or losses on the surface you are trying
to control. While outside devices work best for excluding
summer’s heat, inside insulation work best to keep heat in.

Consider insulating the inside of some of your non-sunny
windows. It may be possible to forgo a few windows (in a
closet or seldom-used room) for the winter. An inexpensive
all-season insulation can be a piece of 1/2-1 inch rigid foam,
tightly fitted inside the window, and left from Nov.-March.
This same foam can be backed with a thin piece of old
paneling or plywood and covered with cloth to be made more
attractive; or if you feel the sacrifice of the window
would be too drastic, then install the foam on Sunday night
and remove it Saturday morning, or use it on a nightly
basis. If you are keen to combine recycling with budget
retrofitting, you could use “bubble-pack” or “foam packing
peanuts,” to loosely fill plastic bags. Use the bags as
fillers between the storm window or door and the main unit.
Remember not to violate proper fire exit routes in the
process, and keep in mind that many of these materials are
flammable. In order to install inside window insulation,
you’ll need to do better than the typical drape, curtain or
shade of the past. The modern approach must involve a
device that is sealed at all edges, as one of the most
important part of the insulation package is the air trapped
between the device and the window.

Good luck to you on your management of all errant Btu’s.