The lighting strategy for living spaces and common areas should first maximize the use of available natural daylight and then augment with artificial lighting. In affordable housing, daylighting can be employed both in the units and in stairwells and corridors, thus reducing the owner's operating costs. Of greatest importance is to provide daylight in the living room, kitchen, and other high-use areas of homes and apartments. For stairwells and corridors, use skylights, roof monitors, and windows to meet basic light needs during daytime hours.

When designing the artificial lighting system, keep in mind that the operating expenses over the life of a lighting system can be up to ten times greater than the first cost. Fluorescent light fixtures save up to 75 percent of the electricity costs over traditional incandescent lights. Fluorescent lamps also last up to ten times longer than incandescent bulbs and produce 90 percent less heat.

FIGURE 3.9. A combined hydremic heating system uses warm water stored in the water heater for both domestic use and to provide heat to the units.

FIGURE 3.9. A combined hydremic heating system uses warm water stored in the water heater for both domestic use and to provide heat to the units.


Vistas at Kensington Park (Dallas, Texas)

Carl Franklin Homes

Vistas at Kensington Park is a community of seventeen new single-family homes in an existing neighborhood in Dallas, Texas, that was developed by Carl Franklin Homes in conjunction with the Dallas Affordable Housing Coalition and the City of Dallas Housing Authority. The energy performance of these homes, for entry-level workforce buyers, was greatly enhanced through the use of structural insulated panels (SIPs) and geothermal heating and cooling units, as well as other efficient technologies. SIPs, which are used for both walls and roof structures on the exterior shell of the homes, consist of a core layer of rigid foam insulation sandwiched between two structural skins of oriented strand board (OSB).

Heating and cooling is provided by geothermal heat pumps, which use the more constant temperatures of the below-surface earth to heat and cool circulated air before returning it to the home. In a place like Dallas, with extreme summer temperatures, geothermal heat pumps are a smart choice, as the earth's temperature remains more moderate. The developer's method of using SIPs and geothermal heating and cooling easily qualified the project for the ENERGY STARĀ® label, while saving residents approximately 50 percent in energy costs as compared with similar conventionally built homes.

The most appropriate type of fluorescent lighting for dwelling units is the compact fluorescent lamp (CFL). Although the initial cost of CFLs is higher than incandescent lamps, the energy savings and reduced maintenance time and expense from lamp replacement make CFLs a cost-effective energy conservation measure. CFLs should be installed in areas with the heaviest use, such as common-area hallways, stairwells, lobbies, and community rooms.

Screw-in CFLs fit into conventional fixtures, just as incandescent bulbs do, and include the ballast with the bulb. Special care should be taken to ensure adequate light levels in order to prevent removal by dissatisfied residents. Most CFLs provide a lumen comparison to assist in selecting the appropriate size. Full-spectrum bulbs of not less than 32 watts should be selected to provide sufficient, good-quality light. Pin-type fixtures consist of the ballast and a socket that can only receive a CFL or other type of fluorescent bulb. The most appropriate places for pin-type fixtures are in the kitchen, bathroom, frequently used ceiling fixtures, and hallway security lighting.

Exit signs should use high-efficiency light-emitting diode (LED) bulbs. These will both reduce energy use by up to 80 percent and lower maintenance costs. One sign alone can save about $15 to $20 annually on electricity costs and can last up to twenty-five years without a lamp replacement.

Lighting controls such as photo sensors, occupancy sensors, and timers save energy by turning lights off when they are not needed. Timers can be located at a light switch, at

FIGURE 3.10. The majority of residential energy use is fo heating, cooling, and appliances.

Electricity Use in Residential Buildings

Dishwasher 2%

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