10.   Electrical and Lighting

Lighting can be divided into two categories: natural and artificial. Daylighting, using windows and other glazing, reduces the need for artificial lighting during the day. At night, or in areas where daylighting can’t reach, LED lighting has revolutionized the field. Available in different fixture types and different lighting colors, from 2700 or 3000K, which can be very similar to incandescent lighting, to 5000 or 6000K, similar to sunlight or halogen lights. Good lighting design includes a mix of general or ambient lighting, focused or task lighting, and decorative or ambience lighting. Low-profile LED fixtures that replace “can” or recessed lights are particularly versatile and loved by designers, homeowners and electricians alike.

Equipment and Appliances. “Plug loads,” including appliances such as refrigerators and devices such as TVs and phone chargers, use a lot of energy, so at minimum choose Energy Star rated appliances when available and compare the amp-hours different equipment needs to do the same task. You may save money initially with low-cost bath fans, for example, but higher efficiency units use electrically commutated motors, which run much more efficiently than cheaper, mechanically commutated motors.

Phantom loads occur when appliances, equipment and devices continually draw a small amount of current to keep their capacitors charged so they turn on quickly, or to stay connected to the internet. When possible, place devices like these on a power strip that you turn off when not in use. 

Penetrations, specifically where electrically-powered equipment and devices require holes in the building envelope—such as exterior lighting, exterior outlets, and electrical service entrances—need a bit more care than they get in typical homes. There are various gaskets, sealants and flashing materials available for this purpose, but don’t leave it to your electrician to make their penetrations air- and water-tight; that’s the job of the general contractor.

Photovoltaic generation. The falling cost of photovoltaic (PV) systems now makes producing your own power a viable option in many places. Living off-grid is generally much less practical than being tied to the energy grid. Most states offer net metering, which pays people for providing power to the grid, usually via PV panels. When annual on-site energy production equals the energy used on site, the house is considered “net zero,” “net zero energy” or “zero net energy” (NZ, NZE or ZNE). For roof-mounted PV arrays, the roof surface should ideally face south at roughly the same angle above horizontal as your latitude (i.e., here at the 44th parallel, roof slopes of about 40-45° are ideal) but newer panels operate efficiently at angles far from ideal. Another option is a ground-mounted array, which may make maintenance easier and allows fine-tuning the position. In either case, the direct current (DC) generated by the panels goes to an inverter where it is converted to alternating current (AC) power, which is then fed to the grid. Or, for off-grid homes, the DC power is stored in batteries, which then goes through an inverter to create AC  power for home use.