Energy Efficient Interior Design
Energy-conscious interior design is the designing and
planning of rooms and specification of materials with the
goal of reducing energy consumption in a home. Energy-
conscious occupants focus on ways to make their homes
thermally comfortable while reducing energy consumption.
Energy-conscious design combines conservation methods,
such as insulation and thermostat set-back, with passive
solar heating. This design approach can be applied to
both newly built homes and older homes. It involves first
making the home as energy conserving as possible, then
supplying the remaining heating needs with solar heat by
increasing the number of windows on the south side to
collect heat (and possibly reducing the number of windows
on the north and west sides), using thermal mass to store
heat, and properly designing and placing walls and
furnishings to allow distribution of heat.
Storage of solar heat occurs in a dense mass material
such as concrete, brick or water. Most mass materials are
hard surfaces that reflect sound. Combining the hard
thermal mass with a large expanse of window glass gives
you many sound-reflecting surfaces. Therefore, if not
absorbed by proper materials, noise can become a problem.
Furniture design should enhance air circulation, and
furniture placement should allow maximum exposure of the
thermal mass to the sun.
Color
The lightness or darkness of a color affects whether
it can absorb or reflect heat and light. Generally, light
values---tints of a hue such as beige, pink or cream---
are used to reflect heat from a lightweight thermal mass,
such as furniture or ceilings, to a more efficient mass
that stores the heat, such as a brick wall. The use of
light values to reflect heat can be balanced by dark
value colors on the thermal mass.
The color used in a room can make you feel warmer or
cooler. Generally, reds, oranges and yellows are
considered warm colors. These would be used where the
actual room temperature is cooler, such as on the north
side of the house where there is no direct sunlight. The
cool greens, blues and violets should be used in rooms
with southern or even western exposure.
Thermal Mass
The thermal mass added to a house enables the solar
heating system to work properly. Mass, in the form of a
dense material, absorbs heat during the daytime to
prevent overheating. lt then stores the heat until the
air temperature of the room drops when the sun goes down.
Then the heat is naturally released from the mass
material, warming the interior throughout the cool night.
This same natural process occurs in the passive solar
home, except that the heat is trapped by the walls or
floors of the house and used to warm its occupants.
(insulation is closed across the windows at night to keep
the heat inside.)
A mass material's effectiveness is measured by its
ability to absorb sunlight, conduct surface heat into its
mass and hold the resulting heat. Mass materials vary
greatly in the amount of heat they retain. Frequently,
older structures are not designed to support the weight of
additional thermal mass. Lightweight, efficient mass is
suggested for many installations. Following is a table
showing the percentage of heat retained by various mass
materials.
The percentage absorption varies according to
material, color, and finish or texture. The best thermal
mass materials would seem to have a dark-colored, rough,
matte surface.
Of equal importance is the need to place furniture so
that it shades the mass floor or wall as little as
possible. The general rule of thumb is to shade less than
30 percent. This will still allow maximum effectiveness
for heat absorption and release. The furniture also
should be raised off the floor slightly so air can
circulate. This means no wall-to-wall carpeting; no large
sectional sofa; no skirted sofas that shade mass floors;
no bookcases on mass walls; and no secretaries or
armoires on mass walls.
Conclusion
Fine tuning your energy-conscious interior design
will take some effort, but it will allow you to reduce
energy consumption without losing design quality.
Here is a list of additional energy conservation
measures that are possible through appropriate interior
design:
1. Covering walls with fabric, gathered on a rod top and
bottom (be sure to flame-proof the fabric).
2. Using closets as buffers on north or west walls.
3. Adding a heat lamp to a bathroom to take the chill
off on cold mornings.
4. Using thermal wallpaper to insulate, foil wallpaper
to reflect heat back into the interior.
5. Using filled bookcases on outside, non-mass walls to
act as insulation.
6. Using large decorative area rugs, tapestries or
fabric wall hangings on outside, non-mass walls to add
insulation.
7. Using carpet and a good pad to reduce heat transfer
through floors, in addition to keeping bare feet warm.
8. Using high-back, overstuffed furniture in northern
rooms to reduce drafts and allow one to become engulfed
(snuggle) in the chair.
9. Using furniture with skirts where drafts need to be
avoided.
10. Using a reversible ceiling fan to pull the air up in
the winter to circulate the warm ceiling-level air
without any draft on the occupant (particularly those
fans placed directly over a seating area). Then reverse
it for summer so the air flows across an occupant,
cooling by evaporation.
Here is a list of products and where to find them to
help conserve energy:
1. Movable insulation: designed to cover and insulate
windows on the interior; can be found at fabric stores,
energy stores, drapery shops and some lumber yards.
2. Mini-blinds: used to reflect sunlight and focus
daylight; can be found in most department or drapery
stores.
3. lnsulated decorative ceiling tiles: added to the
ceilings as insulation; can be found in lumber yards and
energy stores.
4. Thermal wallpaper: used to add insulation to outside
walls; can be found in energy stores, lumber yards and
some wallpaper stores.
5. Vinyl wallpaper: used as a vapor barrier on outside
walls; found in wallpaper stores.
6. Patterned and dyed concrete floors: used as a thermal
mass, cheaper than tile floor and aesthetically pleasing;
inquire of local contractors.
7. Area rugs: used on north walls to insulate, in buffer
areas to insulate or add psychological warmth; can be
found in department and carpet stores.
8. Quarry tile, ceramic tile, brick veneer or paving
brick: used as a decorative treatment and additional mass
over the thermal mass floor or wall; can be found at
building supply firms and some lumber yards.
9. Fluorescent lighting fixtures: used to replace some
incandescent fixtures, especially in bathrooms, kitchens
and utility rooms; can be found in electrical and
lighting supply stores.
10. Other energy-conscious design products can be found
in energy stores or order the Solar Age Resource Book,
Everest House, 1133 Avenue of the Americas, New York, NY
10019.