Energy Approaches
Building Orientation
Your building orientation can have an impact on heating, lighting, and cooling costs. By maximizing southern exposure, for example, you can take optimal advantage of the sun for daylight and passive solar heating. You'll lower cooling costs by minimizing western exposures, where it's most difficult to provide shade from the sun.
Insulation and Air Sealing
There are many new advances in commercial building envelope systems that significantly improve the overall thermal and moisture transfer properties of the exterior walls, windows, and roof. The key is to provide an adequate thermal break to the metal or wood framing and to properly air-seal, both above and below grade. Quality insulation and air sealing also enables you to maintain a comfortable indoor temperature and save heating/cooling costs while protecting your building from destructive moisture and keeping your indoor air free of related molds. Visit our Insulation & Air Sealing page to learn more.
Ventilation
Good indoor air quality is essential for a healthy and productive workplace. Studies show that most indoor spaces contain at least five times the pollutants found outdoors. In general, mechanical ventilation systems remove pollutants (including mold-producing moisture) at their sources. In a predominantly cold climate like Vermont, we recommend an exhaust-only or balanced system to prevent moisture-laden air from gathering in building cavities with cold, condensing surfaces.
For smaller areas (less than 1,500 sq. ft.), electrically-efficient bath fans designed for extended run periods on a 24-hour timer can provide some ventilation at minimal cost. This type of system works best with a tight shell and structural means to facilitate airflow (i.e.undercut doors, transfer grilles). It's most appropriate for new, small buildings with sealed combustion appliances. More involved ventilation systems incorporate ductwork for distribution. This ductwork must be sealed and insulated where necessary. These systems remove or supply air from an arrangement of points. Simple exhaust-only systems use an electrically efficient fan and ductwork to pull air out of multiple rooms or areas.
For larger buildings, heat recovery ventilation systems, also known as air-to-air heat exchangers, make sense. While the volume of air being exchanged and cost of the fuel can vary, the distribution is effective. Return air is pulled from areas with pollutant sources (bathrooms, kitchens) and fresh, pre-conditioned air is exchanged. This requires ductwork that is effectively sealed and insulated where necessary. Consult a knowledgeable contractor if you're planning to integrate a heat recovery system with a forced-air heating and/or cooling system.
Cooling
An overly hot working space is typically due to an abundance of lighting, an improperly air-sealed or insulated building shell, or bare west-facing windows. To reduce cooling needs, replace incandescent lighting with fluorescent lighting; properly air-seal the building shell (which can provide savings in heating needs as well), and incorporate awnings where appropriate on west facing windows. If you're designing a new building with many southwest- or west-facing windows, consider windows with a Solar Heat Gain Coefficient (SHGC) of no more than .32.
If you're installing a cooling system, make it as efficient as possible. Appropriate sizing (i.e.Btu/hour) is essential. Much of the comfort in air conditioning comes from dehumidification. An oversized system often doesn't run long enough to effectively dehumidify, so the air becomes cold and clammy.
If you're considering a central system, a knowledgeable contractor can calculate the peak cooling load and size the system and ductwork appropriately using Manual J (peak cooling load) and Manual D (sizing and ductwork) for the necessary calculations. When outdoor temperatures are cool enough, economizers can run outdoor air through the system. The cool mornings and nights of Vermont summers make economizers a good option for central air conditioning in this area.
Ductwork that runs in attics, basements, or anywhere beyond conditioned spaces should be sealed and insulated effectively. Studies show that without such measures, 20-30% of heated or cooled air is lost.
To learn more about HVAC options for both heating and cooling and available rebates, visit our HVAC page.
Windows and Daylighting
The most cost-effective time to install high-performance windows is when a building is new, or when window replacement is necessary. Quality windows create a more comfortable space while reducing heat loss and condensation. Windows labeled ENERGY STAR® perform significantly better; typically they have a low E-coating, argon gas filling, and a warm edge spacer between panes of glass.
ENERGY STAR qualified windows in a northern climate display a National Fenestration Rating Council (NFRC) label with a unit U-value of no more than .35. Lower numbers mean more savings. All major window manufacturers have double pane windows with NFRC label U-value of .32. Check the window label to verify that the unit is ENERGY STAR qualified for a northern climate. ENERGY STAR® criteria for southern climates identify windows that reduce solar heat gain.
For office buildings with large cooling loads, using windows with low Solar Heat Gain Coefficients (SHGC) can further reduce cooling loads, particularly with windows of a western or southwestern orientation. Look for windows with an NFRC certified SHGC of .35 or less.
Daylighting decreases your need for electric light, creates a pleasant environment, and can have a positive impact on worker morale and student performance. Windows and skylights are used in conjunction with energy-saving controls that automatically dim electric lights when daylight is sufficient. Daylighting benefits are optimized by controlling glare, and by using dimming light fixtures, photocells, and occupancy sensors together as an integrated system. Visit the Daylightingpage to learn more.
Lighting and Controls
Lighting choices benefit far more than your energy costs. Quality lighting can influence the way people feel and perform. It has been shown to increase sales, improve student grades, and raise employee productivity. Visit the Lighting Equipment, Controls & Design page to learn more.
Office Equipment
Computers, fax machines, copiers, and other office equipment are not all created equal. ENERGY STAR qualified office machines use less energy. Equipped with "sleep modes," efficient memory use, and other similar strategies, many of these machines can cut office equipment electrical use by 10-50% or more. Visit our Computers & Monitors page to learn more.