Energy Efficient Interior Design
Energy sensitive interior design is defined as the designing and planning of rooms and the specification of materials with the intention of reducing energy consumption in a home. Energy conscious occupants need ways to make their homes thermally comfortable while reducing energy consumption. Energy-conscious design may combine conservation methods, such as insulation and thermostat setback, with passive solar heating.
This approach can be applied to new and older homes. It consists of making the home as energy conserving as possible, while supplying 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 dense materials like concrete, brick and water. Most mass materials are hard and reflect sound.
The result of combining the hard thermal mass with a large expanse of window glass is 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.
The lightness or darkness of a colour affects whether it can absorb or reflect heat and light. Generally, light values which are 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 colours on the thermal mass. The colour used in a room can make you feel warmer or cooler. Generally, reds, oranges and yellows are considered warm colours. 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.
The thermal mass added to a house enables solar heat to work properly. Mass, in the form of a dense material, absorbs heat during the daytime to prevent overheating. It 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. The percentage absorption varies according to material, colour, and finish or texture. The best thermal mass materials would seem to have a dark-coloured, 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.
Fine tuning your energy sensitive 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:
- Covering walls with fabric, gathered on a rod top and bottom (be sure to flame-proof the fabric).
- Using closets as buffers on north or west walls.
- Adding a heat lamp to a bathroom to take the chill off on cold mornings.
- Using thermal wallpaper to insulate, foil wallpaper to reflect heat back into the interior.
- Using filled bookcases on outside, non-mass walls to act as insulation.
- Using large decorative area rugs, tapestries or fabric wall hangings on outside, non-mass walls to add insulation.
- Using carpet and a good pad to reduce heat transfer through floors, in addition to keeping bare feet warm.
- Using high-back, overstuffed furniture in northern rooms to reduce drafts and allow one to become engulfed (snuggle) in the chair.
- Using furniture with skirts where drafts need to be avoided.
- 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.
Where to Find Products that Help Conserve Energy:
- Movable insulation is designed to cover and insulate windows on the interior; can be found at fabric stores, energy stores, drapery shops and some lumber yards.
- Blinds with a white or neutral backing colour are used to reflect sunlight and focus daylight; can be found in most paint, department and drapery stores.
- Insulated decorative ceiling tiles which are added to the ceilings as insulation can be found in lumber yards and energy stores.
- Thermal wallpaper used to add insulation to outside walls; can be found in energy stores, lumber yards and some wallpaper stores.
- Vinyl (Laminated Sheet Vinyl) wallpaper is used as a vapour barrier on outside walls and found in wallpaper stores.
- Patterned and dyed concrete floors are used as a thermal mass, and are cheaper than tile floors and aesthetically pleasing – inquire of local home centres or contractors.
- Area rugs to be used on north walls to insulate, in buffer areas to insulate and add psychological warmth; can be found in department and carpet stores.
- Quarry tile, ceramic tile, brick veneer or paving brick are used as a decorative treatment and additional mass over the thermal mass floor or wall. They can be found at home centres and tile stores.
- Fluorescent lighting fixtures, as well as screw in fluorescent, used to replace some incandescents, especially in bathrooms, kitchens and utility rooms, are found in electrical and lighting supply stores.
Other energy-conscious design products can be found in energy stores.