Question: How can I improve the energy efficiency of my facility's building envelope?
Answer: Building envelope issues, which include problems with the physical separators (e.g., windows, doors, walls, etc.) between the conditioned (e.g., heated and/or cooled) and unconditioned environment of a building, can take several forms. An energy audit will typically identify energy inefficiencies in one or several of the following areas:
- Improper alignment & operation of windows and/or doors
- Broken or missing weather-stripping around windows, doors, conduits, piping, exterior joints, or other areas of infiltration
- Doors and/or windows left open that shouldn't be
- Excessive expanses of glass on exterior walls
- No insulation between conditioned and unconditioned spaces
- Inadequate or water damaged ceiling/roof insulation
- Blinds and curtains are not used to help insulate the building
The suggested operations and maintenance ("O&M") improvements and facility improvement measures ("FIM") will vary based on your facility's unique mix of inefficiencies, but what follows are some general guidelines.
Suggested Building Envelope O&Ms:
- Realign or re-hang windows or doors that do not close properly. In extreme cases, consider permanent sealing of windows.
- Make sure automatic door closing mechanisms work properly.
- Replace or repair faulty gaskets in garage or on other overhead doors.
- Replace worn and/or broken weather-stripping and caulking.
- Replace broken or cracked windows.
- Post instructions near doors and/or windows being left open.
- Assure that automatic door closers function properly.
- When replacing windows, replace with thermopanes, utilizing the same casings.
- Keep curtains and drapes closed in unoccupied spaces.
- Before replacing water damaged insulation, repair roof where required.
- Verify that vapor barrier faces the conditioned spaces and is intact.
- Instruct personnel to close interior shading devices to reduce night heat loss in winter and to reduce solar heat gain during summer. Place reminders where appropriate.
- Repair or replace damaged or missing shading devices.
Suggested Building Envelope FIMs:
- Resize exterior doors, making them smaller to reduce excessive air infiltration.
- Add expandable separate enclosures, where practical.
- Install self-closing doors on openings to unconditioned spaces.
- Install a switch on overhead doors that prevents activation of heating and cooling units when doors are open.
- Install vestibule doors at major entrances.
- Where practical, cover all windows and through the wall cooling units when not in use.
- In areas with constant strong winds, install wind screens to protect exterior doors from direct blasts.
- Totally or partially insulate non-operable windows. Consider replacing non-operable windows with walls.
- Install double-pane windows.
- Consider adding reflective or heat absorbing film to minimize solar gain in summer and heat loss in winter.
- Install adjustable outdoor shading devices.
- Attach storm glazing to moveable sash of operable windows.
- Insulate between heated/cooled spaces and outside areas, such as parking garages, porticos, storage, basements and attics.
- Add new insulation to meet the recommended standard.