The building envelope includes everything that separates the interior of a building from the outdoor environment, including windows, walls, foundation, basement slab, ceilings, roof and insulation.

Day to day activities

Field Inspection Check List:

• Window inspection – check if there are any broken windows
• Frame inspection (windows and doors) – check if there are any air leakages and whether all joints and penetrations are weather-proofed or otherwise sealed
• Insulation inspection

Recommendations, advice and tips

• Major renovation of the building should be regarded as an opportunity to implement Energy Efficiency (EE) measures
• Planning external insulation (-75% existing U value) retrofit of façade within the framework of general renovation measures may cut its cost (and amortisation time) by about 40%
• Type of insulation – select insulation depending of the place of installation (wall, floor or roof) and R-value
• Ask for a manufacturer’s insulation material certificate. -* Resistance to heat transfer through the insulation is measured in R-value. The greater the R-value, the greater the effectiveness of the insulation.
• The thickness of the insulation should be greater than the legal requirements, so check the existing national laws, standards, and norms
• Only use qualified companies for installing insulation
• Ask for a guarantee for each contractor service
• If you are able to insulate only one surface, make it the ceiling. Adequate ceiling or attic insulation can cut heat loss by as much as 30 percent.
• Always seal air leaks before adding insulation. Silicon caulking is inexpensive and can stop leaks.
• Seal proper openings for plumbing, electricity, refrigerant, gas lines and similar openings in exterior walls, floors and roof etc. forming the building envelope

Special feature: Replacing windows

• When replacing windows, deciding on the type of windows to buy will be among the most important decisions you will make in terms of energy use Because of the impact windows have on both heat loss and heat gain, proper selection of products can be confusing
• The three key features of window energy performance are:
  • U-value (or "U-factor")
  • Solar heat gain coefficient (SHGC) and
  • Air infiltration
• The lower the U-value rating, the better the overall insulating value of the window, and the higher the SHGC the greater the solar energy that passes through the window system. Windows with high SHGC (above 0.7) are designed for colder climates, while windows with low coefficients are designed for hotter climates
• Consider different glazing for windows on different sides of your building to benefit from passive solar energy. Install the lowest U-value windows you can afford on north-facing windows. Select windows with appropriate low-e coatings for your local climate on the east, west, and south sides of your house. If you do order different glazing for your different windows, be sure to keep track of which windows have which type of glazing because they will probably look identical
• Using lower conductivity gas such as argon in a sealed insulated glass window, heat loss can be reduced significantly. Most major window manufacturers offer argon-gas fill as an option in their most popular windows. -* Other gases that have been or are being used in windows include carbon dioxide (CO2), krypton (Kr), and argon-krypton mixtures
• Low-e windows with high solar heat gain coefficients are appropriate for northern climates where passive solar heating is advantageous, while “southern low-e” windows with low heat gain coefficients are appropriate in milder climates where summer cooling is more significant than winter heating.
• Look for windows with wood, vinyl, or fibreglass frames. Be aware that today the frame is the least-efficient part of the window, so check the U-value of the frame too