Perhaps the most important tip to remember for electrical energy efficiency is that if you are not using it, turn it off. If you can’t turn it off, turn it down or unplug it. Beyond unplugging, the following considerations can be implemented to maximize energy savings in buildings.
LEDs are becoming as inexpensive as CFLs and can be used to replace incandescent and CFLs in a building on a regularly scheduled replacement of lamping. For fluorescent lighting, replacing T8 with T5 bulbs and ballast for existing fixtures can be done with less cost then replacing the entire fixture. Some fixtures can have half the bulbs removed and the T8 fixture will still work and can cut power use by half.
Lighting controls are a key to cutting lighting power use.
- Lighting use should match the space use. Program lighting to coincide with when space is occupied.
- Install occupancy sensors for spaces that are used infrequently, such as stock rooms, closets, mechanical closets and cleaning supply rooms.
- Daylight sensors have different considerations for indoor and outdoor applications. Exterior lighting and signage need to be mounted at the proper height above the fixtures they are controlling. Do not mount them below or behind the fixture against the building. Interior lighting sensors are a great option but can require rewiring and significant costs.
Mechanical and Plumbing Equipment
Building management systems are usually not programmed to reflect the building’s true occupancy times. Properly managing the building’s mechanical and plumbing systems programming will yield the largest savings.
- Rooftop units (RTUs) are usually not cleaned and maintained except when they fail. These units have filter and maintenance schedules that should be followed, but because they are out of sight they are out of mind. For example, door gaskets on the RTUs need to be maintained to keep from drawing outside air into the building condition air stream. When RTUs are in economizer mode, they need to all be in economizer mode to keep the systems in balance. Most units are not on a central thermostat control with zoned controls, which reduces their energy efficiency.
- Ventilation system controls are another energy-saving step that usually is not tied into the building management system. Because of this, the systems are ventilating the building 24 hours a day at full occupancy rate. When the building is not at full occupancy, the ventilation rate can be reduced to save energy.
- Pumps should be variable frequency drives and tied into the building management system, saving additional energy based on the building occupancy schedule.
- Mechanical system balancing needs to be checked to ensure even airflow for any conditioned space in a building. The system should be balanced by room or set of office spaces; this balance directly affects occupant comfort.
- Domestic hot-water tanks can be turned off when they are not needed. Turning the temperature down at night and on weekends and holidays saves money. Even though there is a cost associated with bringing the water back up to temperature, it still is less than keeping the water tanks at full temperature all the time.
Major renovations allow for the review of the entire building to cut energy use. Building envelope upgrades can include exterior wall and roof insulation, reflective white roofs, window and door U-values, and increased airtightness of the building envelope. These upgrades allow for the largest energy savings and downsizing of the mechanical equipment while reducing envelope energy losses.
Building programming plays a critical role in specification of the mechanical, lighting and plumbing systems. Selecting a robust building management system that can tie all of the systems together is a critical consideration of maximizing the energy savings, as is matching the occupancy and use of the building with its functions.