Contents:
Why the title Real Energy Savers? Because the tips listed below
go beyond the standard tips which are usually recommended. Standard
tips include: insulating the attic, wrapping the water heater, and
adding storm windows. Implement these real energy savers and start
saving big $$$.
1. Outside air for heater burners with an appropriately sized trap
(Gas, oil, wood, or coal)
Combustion needs fuel and air. If you use air for combustion from
the basement and house, you create a negative air pressure system
inside the house which will draw or induce outside air to be pulled
into the house.
When cold outside air mixes with warm inside air it lowers the
ambient house temperature and causes your heater to go on or stay
on.
Outside air ducted to the air intake of the burner will reduce
the fuel consumption approximately 17% in an average house.
An appropriately sized trap is necessary to resist the colder outside
air from falling in the basement continually in the heating season.
Look to a mechanical tradesperson for your specific size.
2. Dampers for furnace and water heater flues
Open flues and chimneys create an opening in the house which allows
the thermally buoyant warm air
from a basement and/or house to rise out of the chimney. Losses
are significant due to the thermal momentum created by warm chimney
walls.
Warm air loss draws cold outside air into the house and is a chronic
waste of energy.
Proper dampers on the flue will reduce these losses considerably.
3. Reduce thermal air loss vertically through the house and in
the walls of the house
Warm air will rise in any opening in a house (i.e., plumbing or
electrical chases, balloon-framed houses, masonry walls that are
stripped on the inside to receive plaster or drywall and any openings
around windows, doors, baseboards, trims, etc.).
Warm air loss is the largest and single most wasteful energy loser
in some houses. It also creates an inducement which draws cold outside
air into the house.
The solution to this problem is to close any openings that you
find. The most effective way to do this is with a blower door, infrascanner
and monitor. The blower door is a large panel with a fan that adjusts
to a doorway. The infrared scanner with monitor allows you to see
where the heat loss is. Once you know where you are losing warm
air, it s relatively easy to reduce thermal air loss.
Commercial companies can do the scans, reduce the air loss, and
re-do the scanning (Look in the yellow pages under Energy Conservation
and Management Products and Services).
4. Insulation
Ceilings above the living space should have 6 to 12 of insulation.
Vapor barriers should be installed on the warm side of any insulation
situation. The only function of insulation is to reduce thermal
conductivity. It does not stop air infiltration.
Though wall insulation is beneficial, it is only recommended when
you can blow in 3 1/2 and when the workmanship can be verified by
an infrared scanner to check for leaks and uneven application.
5. Storm windows
Storm windows have two basic functions: (1) reduce air infiltration
and (2) protect the main windows from the weather.
Storm windows should be installed on wood thermal breaks if the
main windows are metal.
Storm windows have very little effectiveness as far as saving energy
if you do not address energy
saving tips #1, 2, and 3 listed above. The negative air pressure
system that tips #1, 2, and 3 create will simply cause cold air
to be drawn into the house from some other place.
6. Weather stripping
Give doors and windows a tight seal with weather stripping. This
will reduce air infiltration. To realize the maximum benefit from
weather stripping you must implement tips #1, 2, and 3.
Look for more real energy savers in a future column.
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The energy saving tips listed below go beyond the standard tips
which are usually recommended.
Standard tips may include: insulating the attic, wrapping the water
heater, and adding storm windows. Implement real energy savers and
start saving big $$$.
1. Siding
The main function of siding is to keep the weather out of the house.
The inability of siding to keep cold air from getting behind it
makes it practically useless as an energy saver.
Note: Insulated aluminum siding does not insulate at all because
air easily gets behind the siding.
To reduce air infiltration into the exterior walls you must wrap
the house before you install any siding. The wrap must be able to
stop air and cannot be allowed to trap moisture permeating from
the inside of the house. DuPont s Tyvek is an excellent material
for this use.
2. Set-back thermostat
It s advantageous to have the heat at lower settings when not at
home or sleeping. With this type of thermostat, you can select in
advance the times you would like the heat to go on and off.
3. Computer thermostat
This type of thermostat will allow you to program much more information
than a set-back thermostat,
such as different settings for weekdays and weekends.
The computer thermostat is especially advantageous with a heat-pump
because you can program it to
override back-up electric heat unless the outside thermostat requires
it.
NOTE: One of the most inefficient aspects of a heat-pump is the
improper use of the thermostat. The computer type thermostat can
enhance its efficiency.
4. Ventilation
Condensation is caused when warm air (which has more ability to
hold water than cold air) moves into
an area with colder air.
Large quantities of air are needed to carry off air that may become
saturated. The best way to develop good ventilation is with high-low
ventilation (i.e., ridge vents and soffit vents).
Note: Insulation that absorbs moisture from saturated air has little
or no effectiveness as an insulator and can actually increase the
conductivity of the insulation.
The formula for proper ventilation is one (1) square foot of clear
air distributed 50% high + 50% low
for every 300 square feet of attic space. Additional ventilation
is necessary if the insulation does not have a vapor barrier.
5. Heaters
Heaters waste 25% to 50% of your total heating fuel.
The design of the heater, type of burner, and fuel used will dictate
how much waste goes up the chimney.
The main questions to ask when you are in the market to buy a heater
are:
- What is the temperature of the flue gases? This will be dictated
by the heat exchanger or boiler design. The lower the exhaust
temperature, the more efficient the unit will be.
- What is the overall efficiency, including fuel, chimney, and
heat transmission losses?
6. Water heaters
The most economical way to save energy with water heaters is to
keep the temperature at approximately 120 to 130 degrees, depending
on your usage demands.
Wrapping water heaters is OK. However, the savings are minimal
in 95% of the cases.
When buying a new water heater, you should buy a heater only as
large as you need (i.e., an average family of four will get along
satisfactorily with a 30 gallon gas-fired water heater).
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One of the ways a house loses and gains heat is through conduction.
Conduction is the movement of heat through solid objects, such as
walls, the ground, floors and ceilings. Heat always moves toward
the cold, trying to equalize the temperature, and does move through
solid material. Heat inside a warm house will always try to escape
and, in the summer, the heat outside tries to get in.
Insulation in floors, ceilings and walls is helpful because it
traps tiny pockets of air that retard the transfer of heat. Insulation
won’t stop heat entirely, but will slow it down.
Insulation’s effectiveness is indicated by its "R-value",
which is its ability to resist heat flow from warmer to cooler areas.
The higher the R-value, the more effective the insulation. It is
important to remember that a material’s insulating ability
is based on R-value, not thickness.
Types of Insulation
- Batts and blankets-Fiberglass. The R-value per inch is 3.1 to
3.5. It is best suited for standard joists, studs or rafter spacing
in attics, walls and the underside of floors.
- Loose fill - Cellulose, fiberglass and vermiculite. The R-value
per inch is 2.2 to 3.7. It is best suited for non-standard spacing,
infill of block walls and spacing between joists that have obstructions.
- Rigid board-Polystyrene, polyisocyanurate, urethane and bead
board. The R-value per inch is 3.5 to 5.5. It is best suited for
basement walls, foundations, exterior walls, interior walls and
cathedral ceilings.
Where to Add Insulation to a Home
- Living area ceilings below an unheated attic.
- Living area floors above unheated basements, crawl spaces, garages
and open porches.
- Uninsulated exterior frame walls.
- Between sloping rafters. Be sure to leave an air space for ventilation
between the insulation and the roof sheathing. (Select insulation
accordingly.)
- In the back of band or header joists around the perimeter of
the basement.
- Basement walls when below-grade space is finished for living
purposes or when the basement doesn’t enclose a fossil-fueled
furnace or boiler (gas/oil).
- Basement walls where the above-grade exposure exceeds 50 percent
of the interior wall surface.
When adding insulation in the attic, keep at least 1 1/4"
space between the insulation and the sheathing to allow air for
the soffit/eave vents to flow to the ridge and/or gable vents.
The Cost to Add Insulation
You can expect to pay 65 cents to $1 per square foot for insulation,
including labor and materials.
In the attic, a contractor will install about 9" of insulation.
If you have a 1,000-square-foot attic at an insulation cost of $650
to $1000, you can expect savings of $125-$200 per year, depending
on the climate. Your payback would occur in five to six years.
Insulating walls is generally an economic loser. Also, the walls
are much more difficult to insulate. It requires drilling holes,
filling walls and using an infrared scanner. Walls also have much
more square footage to insulate than the attic. With 4,000 square
feet of walls in an average house, the cost may be $3,500-$4,500.
You won’t break even on your investment for 15-20 years. A
better option is to address the air infiltration and air loss.
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One of the most frequent, and least recognized, problems home owners
have is inadequate attic ventilation.
Poor Attic ventilation problems can lead to excessive heat in attic
spaces in summer, which will prematurely fatigue a roof require
additional cooling of the living spaces below. During the winter,
moisture from indoor activities migrates from the living spaces
to the attic - delaminating plywood, rotting roof sheathing and
framing members.
How To Tell:
Rusted nails and stained roof sheathing are initial signs of a
ventilation problems.
Two tests help determine if there is sufficient ventilation in
an attic.In the winter, look for moisture or frost on exposed nails
at the underside of the roof sheathing during very cold weather.
On a warm, windless summer day, there should be a maximum 10 to
15 degree temperature difference between the air in the attic space
and the outside shade.
Here are some cures for poor attic ventilation:
- Ventilation Systems: Ridge and soffit vents allow natural ventilation
of the attic. Cool air enters at the soffits under the exterior
roof overhangs. As this air warms, natural convection pushes it
to the ridges at the top of the roof where it vents to the outside.
- Power Fan: During summer operation a thermostat automatically
operates a roof or gable-mounted fan as needed to force air circulation.
For proper moisture control in winter the fan should be operated
by a humidistat, placed at the lowest point in the attic on the
north side, or a clock timer for two (2) minutes each hour during
cold weather.
- Blocked Vents: Clearing up blocked soffit vents often cure a
ventilation problem.
Adequate attic ventilation all year around is important to the
long term health of your house, reduced heat and cooling loads,
and for optimum interior comfort.
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Putting a housewrap on a home is much like putting on a windbreaker
on a windy day. So, why does a new home need a housewrap? Homes
have thousands of places where building components come together,
and everywhere that they join, there's a crack or a gap. That causes
air to filtrate in, which causes you to be more uncomfortable and
raises your energy bills. It's important to control air infiltration,
because every time that air infiltrates into a house, that pushes
out the air that has already been paid for to heat and cool.
Perhaps you have heard a house whistle, heard air blowing through
it, or have felt wind coming through an electrical outlet. A housewrap
will prevent all of these symptoms. It seals up a lot of those cracks
and gaps that would be difficult to do with caulking. Eventually,
caulking wears out; where an air barrier wrap, it's there for the
life of the home.
When a house is wrapped, a builder takes the housewrap and wraps
it around the entire home. They then return and X-cut around the
windows and doors and flash around the windows. This process allows
everything to be covered.
If a new home does not have a housewrap, it will lose energy. For
example, if there is an R-13 wall and a 9-mile-an-hour wind blowing
across the home, the apparent R-Value of that insulation is reduced
down to about 5, More than 50% cut in R-Value. Lack of a housewrap
is one reason why one gets cold even in a brand new house, or gets
warm in the summertime.
Moisture has to be paid attention to since there is new moisture
every day inside a house, with showers running, pots and pans boiling
water, people just talking. An average family puts out about 70
pounds of moisture a day, and it's important that moisture has a
way to get out of the home.
Depending on the part of the country, and a variety of other circumstances,
a homeowner can save several hundred dollars a year on energy bills.
And insulation of a housewrap probably will not cost more than $500.
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