Reducing Home Energy Use
Prepared by GMM Committee on Global Warming
Solar energy is the world's most important energy resource.
But the balance of absorption and radiation is critical.
Energy Sources Worldwide, 2004.
Our energy comes mostly from carbon-based sources.
World energy use has risen tremendously.
Transportation and Residential take half of the total energy.
We can make a difference here.
Part of the problem is energy efficiency: more than half is currently wasted.
The energy available from the sun can suffice for our needs.
We can make use of it from wind-power and from solar collectors.
Solar cells generate electricity directly from sunlight.
This solar collector concentrates the sun's rays and
generates electricity directly from photovoltaic cells.
This solar parabolic dish 24 feet in diameter collects 30,000 watts.
The energy is converted to electricity at 30% efficiency by
a small heat engine.
The Solar Electric Generating Systems plant in the Mohave
desert is the largest solar collecting plant in the world. An array
of parabolic trough reflectors heats oil which transfers the heat
efficiently to the electric plant, where steam turbines generate
electricity. This plant has 400,000 mirrors in 1000 acres and
generates 354 MW of power.
More of these plants are under construction, and many are
planned for N. Africa and the US Southwest.
The Ausra system uses flat mirrors which are less expensive
and stronger than curved mirrors.
They can be turned over to protect against the weather.
Solar heat can be utilized by anyone. A simple enclosure with reflector
can cook a meal. A solar concentrator can cook quickly.
250-300 deg F
400-500 deg F
Some facts about solar power:
1) A solar thermal power plant built on about 1% of the
surface of the Sahara Desert (200 miles squared) would
be sufficient to generate electricity for the whole world.
2) Solar thermal power can used be with energy storage
systems or combined with other energy sources to
provide all day power.
3) Solar thermal power is reliable and available when
needed most - during peak demand hours
4) Solar thermal power can be cheaper than power from
fossil fuels when all external costs are considered (and
even when they're not).
Arrays of solar photo-voltaic panels are being installed everywhere.
They pay back in energy terms in 1-2 years, and in money in about 30 years.
CIS Tower, Manchester, “Solar tree” in Gleisdorf, Austria
Most of the energy we use at home is for heating and cooling.
USA Household Energy Use, 2004
A very important way to reduce carbon emissions
is to purchase wind energy from PECO.
It only costs 2.54 cents/kWH more than carbon-based
electricity (15 cents/kWH), so costs only about 17%
And here are some more ways:
Install a more efficient home heating system.
a) Modern high-efficiency furnaces are twice as efficient as
traditional designs. More of the heat from oil or gas is converted
into heat for your house, and less heat goes up the chimney. To
justify the added cost, add up the savings you will get over 20
years. When you sell your house, you can get a higher price if the
buyer knows that the heating bill is very low.
b) Install a modern thermostat that turns heat off during day and
night when heat is not needed. Set thermostat at day=65,
night=55 deg F.
c) Install a geothermal heat pump. This is about 3-fold more efficient
than electric heating. It is more expensive to install than a furnace
burning fossil fuel but it pays back in 3-5 years.
d) Install a solar heating system.
Insulate your home and living spaces.
a) Add insulation between exterior and interior walls and in the
attic floor. An excellent choice is cellulose, because it is resistant
to air currents, is fire-resistant, and can be blown in through
holes drilled in the plaster. Other good choices are “expanded
polystyrene” and “phenol-based” foam. This is especially important
on the second and third floors of your house, because they are
generally warmer (heat rises). Fiberglass is less effective because
it allows air flow. Good insulation can save up to 50%-75% of your
heating bill and will pay back in 5-7 years.
b) Replace old windows with thermo-pane style (2 layers of glass).
Add storm windows on the outside of your house.
c) Cover air spaces and cracks around windows and doors with
weather-stripping. Cover leaky windows with plastic, seal around edge.
d) The GMM Property Committee is considering all of these ideas. Another
possible course might be to add insulation on the outside of the walls.
This is called EIFS (“Exterior Insulation Finishing System”).
Insulate windows & frames.
a) Modern double-glazed (“thermo-pane” or “insulated glass”) windows
have 2 panes of glass which are sealed around the edge. This provides
insulation between the panes and reduces the amount of heat that can
pass through the window.
b) For double-glazed insulated window, the loss of heat is:
Loss = 10 R-val
L = 0.56 watts / m2 / deg C
For 10 degC (18 degF), the loss is 5.6 watts / m2
c) Several types of window frame are available. A good choice is wooden frames because
the wood has relatively good insulation properties. For better weather resistance, some
modern windows are coated with plastic (vinyl or PVC). Metal window frames are also
available but they may not have as much thermal resistance.
d) You can improve insulation with curtains and window blinds (when they're closed).
They can add an extra R 1-2 to the window's total insulation.
R-Values for insulation materials
Single-pane glass window R-1
Double-pane glass window R-2
Thermo-pane (double-glazed) window R-10
Air, convective R-1/inch
Drywall, 1/2” R-0.45
Concrete, stucco R-0.1/inch
Concrete block, 8” R-1.1
Brick, 4”, common R-0.8
Asphalt shingles R-0.45
Wood shingles R-1
Wood panels (sheathing) R-1.25/inch
Fiberglass batts R-2 - R-3.85/inch
Cellulose loose-fill R-3 - R-3.8/inch
High-density fiberglass batts R-3.6 - R-5/inch
Molded expanded polystyrene R-3.7 - R-4/inch
Urea-formaldehyde panels R-5 - R-6/inch
Polyurethane panel R-7/inch initial - R-6
Polyisocyanurate panels w/foil R-6.8/inch initial - R-5 aged
Vacuum insulated panel R-30/inch
Thinsulate clothing insulation R-5.75
How to calculate R-Values for typical house wall
Estimate of R values of stone/brick walls
1 R-value of 12” stone wall = R-0.15/inch = R-1.8
R-value of 1" air space =
R-value of wooden studs =
R-value of wood lath, plaster =
2 Total = R-4.3
R-value of wood siding =
R-value of 1” air space =
R-value of 2” foam insulation = R-5/inch =
R-value of wooden studs =
R-value of 1/2” drywall =
Total = R-13.8
EIFS - Exterior Insulation Finishing System
“Drainable EIFS” is:
1) Foam insulation board attached to the wall.
2) A durable, water-resistant base coat is applied on top of the
insulation, into which is embedded a layer of coated fiberglass
3) A finish coat gives the insulation a stucco-like appearance.
4) Flashing is installed around windows and between joints to
allow trapped water to escape.
EIFS works well on the outside of stone or brick buildings. It is
compatible for retro-fits because it does not disturb the inside
of the building. Because it keeps the stone/brick wall warm in
winter, there is little tendency for moisture condensation and
therefore a moisture-barrier on the inside of the wall is
Typical EIFS R-value = 20-30/4”
To improve efficiency, get a home energy audit.
a) Air leakage.
b) Thermal efficiency of walls and windows.
c) Efficiency of furnace.
For sustainable home heat, use solar, wood or geothermal:
1) Wood burned in a stove does not add carbon to the atmosphere
because atmospheric carbon is incorporated into new tree
2) A modern wood stove can burn very cleanly without adding
smoke to the atmosphere because it has an “after-burner” like Catalytic combustors
modern automobiles, which makes the stove more efficient. for wood stoves
3) Solar energy is an excellent fit to the requirements for house
heating. The basic requirements for solar heating are:
a) an insulated window.
b) a way to transfer the heat into the house where it is needed.
c) a way to store the heat. A modern method is called
“seasonal heat store”, where the heat is stored for weeks
or months in the foundation of the house.
4) There are other possibilities for heating, such as heat pumps
and geothermal, running on wind-powered electricity. These
are efficient when combined with solar.
Simple solar heating
Solar energy for heating homes:
1) Passive solar energy heating means adding large windows to the
south-facing side of a house, and then adding some heat storage
capacity to the house, typically in the form of masonry or tanks
of water. The heat storage capacity is large enough that the
temperature of the house does not fluctuate much between sunny
and cloudy days.
2) A very effective way to add solar heating is to use awnings and
plant deciduous trees on the south side of the house to provide
shade in summer. Then add or enlarge south-facing windows Passive solar heating system.
that capture the sun's rays in winter.
3) Active solar energy heating means adding solar collectors
that heat air or water, which is pumped into a storage
system. The system can be very simple and inexpensive
or can be more complicated and large enough to heat
4) The term “seasonal heat store” means a solar storage
device (insulated earth or water tank) that is big enough
to store summer heat, then release it during the winter.
An active solar collector system.
Install a green roof. This absorbs rain and cools the building naturally.
Install a geothermal heat pump.
1) A geothermal heat pump is about 3-fold more
efficient than electric heating and is competitive
with fossil fuels.
2) In the winter, it draws heat from the ground,
concentrates it, and transfers it to your house,
much like running a refrigerator backwards.
3) A geothermal heat pump is more expensive than
a furnace burning fossil fuel but it pays back in
4) A geothermal heat pump can be reversed for air
conditioning in the summer.
5) Geothermal wells are being installed at Friends Center
and for the new GFS Science Building on Coulter St.
GFS Science building
How a Seasonal Heat Store works:
1) A field of geothermal boreholes is drilled, a
piping system installed, and then covered
2) Standard solar panels collect heat during the
summer. The heat is pumped into the heat
storage boreholes. Over several months the
temperature gradually increases.
3) During the winter, the heat is pumped out
of the heat storage to heat the houses.
The houses are super-insulated with
sustainable materials so they don't require
4) This design went into operation in 2007 at
Drake Landing Solar Community in Okotoks,
Increase efficiency of domestic water heating:
1) Set water temperature lower, 130-135 degrees F. It should be higher
than 125 deg to prevent disease.
2) Add a blanket to your water heater. This reduces loss through the
insulation in the outer wall. Insulate your hot and cold water pipes
3) If you have water-based radiators or baseboard heaters, purchase a
home furnace system integrated with a water heater. The furnace
heats your radiators and also the hot water for your kitchen and bath.
This is more efficient because the hot water storage tank does not
need a flue.
4) Purchase an “on-demand” electric or gas-based hot water heater.
This heats water instantly so a large tank filled with hot water is
5) Purchase a solar collector and add it to your system of hot water
Solar energy for domestic hot water:
1) You can add a solar collector to your house very easily.
Many brands of collector are available, ready to install.
2) Solar collectors can be connected to your hot water tank
for domestic hot water throughout the year.
3) Solar collectors pay back in 7-10 years and are durable for
Reduce electric energy use:
1) Electric lights -- use compact fluorescents.
2) Air conditioner -- use fan.
3) Refrigerator/freezer -- purchase new efficient model.
4) Electric dryer -- use clothes line instead.
5) Unplug AC wall socket power supplies for devices such as
cell phones, radios, and TVs in when they aren't being used.
6) Check your power meter and see if you can count up all the
watts you are using in your house.
To increase the efficiency of lighting,
Install compact fluorescent (CF) bulbs:
a) They convert more of the electricity into light and therefore use
80% less energy of a corresponding incandescent bulb, and they
last longer (5-7 years). Depending on how much use the bulbs
get, the savings from this and the extra lifetime from CF bulbs pays
for their extra cost in a few years.
b) They last the longest when not turned on and off a lot.
c) They are available in several color termperatures:
“warm-white” (2500-2700 deg K), similar to incandescents,
“medium-white”(2900-3000 deg K), better for most purposes,
“cool-white” (4000 deg K), like traditional fluorescent tubes,
“daylight” (5000 deg K), more accurate seeing of colors.
d) Outdoor CF bulbs are available to withstand rain and cold. It is
often helpful to put them on an automatic photocell or motion detector
switch so they aren't left on all night. Special CF bulbs are available
for dimmers. When installing in closed fixtures, check heat generation.
Some commonly available compact fluorescent bulbs.
14 watt CF = 60 watt incandescent.
20 watt CF = 75 watt incandescent.
25 watt CF = 100 watt incandescent.
To increase the efficiency of air conditioning:
1) Use fans instead of air conditioning whenever possible. Overhead
fans make the heat and humidity bearable by evaporating
moisture to cool the skin. Drink plenty of fluids so you don't
become dehydrated by the heat.
2) Window fans are helpful at night to bring in cool air from outside
the house. A fan set to turn off at 2 AM is helpful – you can turn
on the fan when going to bed, then it will turn off automatically.
3) Only use the air conditioner when you need it. A typical small
window air conditioner typically uses 1500 watts, which over an
8 hour day costs about $2. Larger units use more.
4) Purchase the most efficient air conditioner possible. Check the
Seasonal Energy Efficiency Rating (SEER) number – it should be
at 13 or above, although smaller window units often have lower
ratings. You can save 30% on an upgrade from SEER 9 to SEER 13.
5) Make sure that the doors to the room where it is located are kept
shut, and that the room is insulated well.
6) Install a geothermal heat pump for heating in winter and air-
conditioning in summer.
To increase efficiency of refrigerator/freezer:
1) Purchase a “super efficent” (SERP) unit. The most recent
refrigerators use less than 1 kWH/day, and use less than $40 of
electricity per year. Look carefully at the energy label and
compare models and brands. Sun-Frost has been the most
efficient brand but it is expensive and other brands have
competitive efficient models. To justify spending more, add
up the savings you will get over 20 years.
2) Keep the condenser coil at the back of the refrigerator clean
and free of dust, with plenty of space for circulation of air.
3) Place the refrigerator in a cool room. This lowers the amount
of time it must run to remain cold.
4) Purchase a super-efficient top-loading freezer and place it in
a cool room. This type is more efficient and loses less cold each
time you open it.
5) Remember that electricity is a valuable resource, much more
valuable than it costs. Give yourself a 100% electricity tax,
and spend it on new ways to reduce energy use.
To increase efficiency of drying clothes:
1) Use the sun when you can. Set up wash drying lines outside in the
back yard, and in the basement where you can hang up clothes to dry.
This can save up to 20% of your electric bill. Partly drying in the sun or
wind will save money – the dryer can finish it off.
2) Remember that an electric dryer consumes the most electric power of
all the appliances in a typical home (4000-6000 watts). Use it sparingly
and wisely. Don't put wet clothes in the dryer – they should be spun
dry by the washer. The best dryers have a moisture sensor in the drum
to stop the drying cycle. This can save 10-15% over a timer.
3) Always clean the lint filter after each use – this can save 20%. Use an
external exhaust vent, but make sure vent is metallic because lint can
cause a fire.
4) You may have heard that gas dryers are more cost-effective than
electric dryers. The cost of drying a typical load is $0.40 in an electric
dryer and $0.20 in a gas dryer. But, please note that gas creates carbon
dioxide, whereas wind-powered electricity doesn't.
5) To keep the “fluffy” look from the electric dryer, put clothes in for
only 5 minutes, then hang them up to dry outside or in the basement.
To minimize energy use in transportation:
1) Walk or ride a bicycle whenever possible. This gives exercise
and is generally much more healthy. When shopping, go with
a bike rack or shopping cart so you don't have to carry the
2) Take a train or bus instead of driving or flying.
Trains are more energy-efficient than most other public
transportation methods. A bus is more efficient than
driving – you can find the schedule for city-to-city routes
on the Internet.
3) Car-pool to work or to events. You can effectively double
or triple your mileage by driving 2 or 3 people.
4) Support higher gasoline taxes which will tend to reduce
gasoline usage and support development of more efficient
means of transportation.
To reduce energy use in your car, improve your miles per gallon:
1) Keep up your car maintenance. Keep the tire pressure high,
because a more fully-inflated tire is easier to move. Keep the oil
level correct with the proper oil weight. Check the air filter.
2) Minimize speed, for speed increases friction, which requires more
engine power and uses extra gasoline. Slowing from 70 to 55 mph can
increase your mileage by 25%.
3) Minimize acceleration by pressing gently on the accelerator and
brake pedals. When going up and down hills, allow speed to vary
according to the slope: when going up, allow the car to go slower,
and when going down, allow the car to go a little faster. In start-
and-stop city driving, taking an extra 15 seconds to get up to
speed and 15 seconds to brake can increase your mileage by 20%.
4) Purchase a higher efficiency car, rated 35 mpg or more, with manual
transmission. Keep the engine in its the low-to-medium RPM range,
which is most efficient. Keep the car as light as possible. Remove the
roof rack when not needed. Don't run the air conditioner unless you really
need it. The recently-developed “hybrid” cars get higher mileage,
especially in city driving.
An electric or hybrid vehicle is more efficient because it can regenerate
electricity during braking. The engine charges a battery or ultracapacitor,
which runs the electric motors attached to the wheels.
When braking, the electric motor acts like a generator to
make electricity, which is stored in the ultracapacitor.
To save energy in several ways, dig a garden and plant some vegetables. You will
be healthier and will save money and gas from fewer shopping trips.
Support your local Community-Supported Agriculture farm. You will help
local farms be competitive with agri-business and this will save energy and
give you healthier food.
National and State policy issues to help prevent global warming:
1) Encourage energy efficiency at all levels of government and the private sector. This
should encourage business, providing greater profitability and more jobs.
2) Implement carbon use tax on major sources of fossil fuels to provide monetary
backing for sustainable energy sources and to shift demand from carbon to sustainable
3) Start new research initiatives in generation of solar electricity and hydrogen, fuel
cells running on hydrogen, and biomass conversion.
4) Encourage private industry in efforts to build solar electricity and hydrogen plants,
convert vehicles to hydrogen, build wind farms, and use renewable sources and solar
for energy. Increase grants and loans to promote investment in renewable energy.
5) Encourage utilities to implement smart electric meters to reduce electricity use
during times of high demand. Give rebates for purchasing more efficient home
appliances like refrigerators and air conditioners. Increase tax credits for residential
and commercial solar-energy installations.
6) Join with the international community to reduce emissions of greenhouse gases and
standardize economies around the use of solar and renewable energy sources.