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Evaluate and install low-e window film.

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Installing high-performance low-e window film to the inside of your hospital’s windows can decrease building energy use; improve window insulation performance; lower year-round HVAC loads; and shorten HVAC equipment run times, reduce dependence on artificial lighting, and increase patient and staff satisfaction and comfort levels. Window film can also be used to provide UV protection, safety and security, privacy, decoration, and graffiti protection.

  • Project Talking Points

    • Uncontrolled daylight coming in through windows can cause glare, patient and staff discomfort, warm temperatures, hot/cold spots, and HVAC systems to run excessively to try to keep up.
    • A building’s directional orientation can create areas that receive significantly more sunlight than others. Depending on the sophistication of a facility’s HVAC system, this can create challenges for maintaining comfort.
    • A major component of any building envelope is its fenestration (windows, doors, skylights, and curtainwalls). A 10% to 40 % reduction in lighting and HVAC costs can be achieved by improving the energy efficiency of fenestration of commercial buildings, according to the National Institute of Building Sciences.
    • According to the U.S. Department of Energy, windows account for 10% to 25% of heating bills, and are the greatest source of heat loss or gain in any building.
    • According to the Center for Climate and Energy Solutions, space heating, cooling, and ventilation account for the largest amount of end-use energy consumption in buildings.
    • Using window film to control the sun’s heat allows patients and staff to leave blinds and curtains open and enjoy outdoor views and exposures with controlled daylight. This can improve health and well being for patients, reduce exposure to harmful UV rays, and increase productivity for staff members. (See links at the bottom of this section for more information.)
    • Low-e window film has been proven to offer significant savings on both heating and cooling costs with metered measurement and verification of cooling and heating savings.
    • Studies have shown that low-e window film can provide a significant increase in useful daylight (and in patient/staff satisfaction and comfort levels).
    • Utility rebates are available to reduce installation costs of low-e window film.
    • Window film is a retrofit solution for facilities professionals who want to control solar heat gain and glare, provide UV protection, and experience year-round insulating benefits of low-e coatings.
    • No special maintenance is required for low-e window film.
    • Window film was named the most cost-effective energy-saving choice for Californians when used in retrofit commercial building projects.
    • Advancements in window film have led to film options that aren’t overly dark and don’t produce an iridescent shine.
    • A study of the top five energy retrofits based on ROI identified window film as one option that offers a quick return on investment.

    Links to studies/surveys citing correlation between daylight exposure and health/productivity:

  • Triple Bottom Line Benefits

    • Cost benefits:
      • The year-round energy savings from low-e window film translate to savings in heating and cooling costs.
      • Most “standard” (non-low-e films) provide cooling-season-only savings.
      • The majority of commercial and institutional buildings, including hospitals, can expect a return on investment from window film in less than four years.
      • A study of the top energy retrofits based on ROI named window film one of the best retrofits for offering a quick return on investment.
      • Utility rebates and tax credits can make a full ROI possible even faster.
      • An independent analysis also shows that window film installation is the most cost-effective, energy-saving retrofit for California building projects when compared to updating HVAC systems, adding insulation, or improving air sealing and caulking.
    • Environmental benefits:
      • Because low-e window film reduces energy use, this green product can help reduce your building’s greenhouse gas emissions through decreased electricity and heating fuel consumption for HVAC purposes, and also prevents unnecessary window replacement due to poor window insulation efficiency.
      • Fewer window replacements means that windows are kept out of landfills longer. Window film can also help hospitals achieve LEED certification (see the “Cross References: LEED” section).
    • Social benefits:
      • Numerous studies have shown that exposure to daylight and outdoor views can improve health and well being for patients, and decrease length of hospital stays.
      • Daylight has also been shown to improve productivity and efficiency for staff members.
      • When blinds and curtains are closed, the benefits of daylight and outdoor views disappear. Low-e window film offers improved comfort without blinds or shades, which translates to improved levels of natural daylight.
  • How-To

    1. Assemble team members who might be involved in the decision-making and/or installation process. This could include facilities and maintenance staff, building engineers, energy managers, healthcare engineers, administrators, and chief nursing officers.
    2. Assess the condition of your hospital’s windows; determine that there are no leaks or cracks. As long as the windows are in good condition and don’t need to be replaced due to broken or damaged components, low-e window film can be applied to almost any type of window, including windows with “tint” built into the glass (bronze, green, gray, or blue glass) and dual-pane windows.
    3. Evaluate whether there are currently solar coatings or low-e coatings on the existing windows. This may affect which type of low-e window film will work best. If the wrong type of window film is paired with the glass, thermal stress may cause glass failure.
    4. Discuss temperature and discomfort issues with staff, especially if opposite sides of the building feature high levels of glass. Are there certain patient rooms or staff work areas that suffer from warm temperatures, too much glare, or fading of assets?
    5. Determine whether your hospital could benefit from saving HVAC energy use year-round, and whether HVAC systems would benefit from reduced runtimes and heating/cooling loads.
    6. Analyze interior building spaces to determine where hot or cold spots might be, how comfortable interior temperatures are near windows, and which windows are exposing patients and staff to harmful UV rays.
    7. Determine whether any hospital assets need protection from fading due to UV ray exposure (artwork, flooring, window coverings, wall coverings, etc.).
    8. Select the right low-e window film for your facility based on energy performance, solar heat gain coefficients, and visible light transmittance figures. Look for an NFRC rating label that outlines solar heat gain coeffi­cient (SHGC), U-factor, and visible transmittance (VT). Manufacturers can provide other window film performance data, such as UV blockage, glare reduction, and security features.
    9. Professional installation for low-e window film is required for warranty coverage; search for an authorized installer in your area that installs the type of low-e window film you’re looking for.
  • Tools

    At this time, there are no simple calculators available that can accurately predict energy savings from window film. Energy savings from window film application can only be estimated using a whole-building energy model (eQUEST, DOE-2, EnergyPlus) that takes window performance into account. Several factors should be considered when calculating possible savings, including building orientation, type and age of HVAC system, type of low-e window film in consideration, existing glass type, window-to-wall ratios, etc. 

  • Regulations, Codes and Standards, Policies

    Beginning in 2014, window film will be incorporated into California state building code. Window film will be recognized as a building product just like glass or roofing materials, but primarily for retrofit applications. The new building code for window film will require a National Fenestration Rating Council (NFRC) certification label, the manufacturer’s name, a 10-year warranty certificate, and compliance with the International Window Film Association’s Visual Quality Standards.

     ANSI Standards ASTM E903 and ASTM D1044-93 relate to solar/UV transmission properties and abrasion resistance. Major window film manufacturers use these standards to guarantee the quality of their raw materials and finished products.

     ANSI Standard Z97.1 relates to the installation of glazing systems and safety requirements. The goal is to reduce or eliminate unreasonable risks of death or serious injury when glazing material is broken by human impact.

  • Cross References: LEED

    Window film can be used to help achieve LEED certification, providing up to nine LEED points total.

    LEED for Healthcare (2009): New Construction and Major Renovations

    • Sustainable Sites Credit 8: Light Pollution Reduction (1 point)
    • Energy & Atmosphere Credit 1:  Optimize Energy Performance (1-3 points)
    • Indoor Environmental Quality Credit 6.2:  Controllability of Systems-Thermal Comfort (1 point)
    • Indoor Environmental Quality Credit 8.1:  Daylight and Views-Daylight (1-2 points)
    • Indoor Environmental Quality Credit 2.4:  Daylight and Views (1-2 points)

    LEED for Existing Buildings (2009): Operations + Maintenance

    • Sustainable Sites Credit 8: Light Pollution Reduction (1 point)
    • Energy & Atmosphere Credit 1: Optimize Energy Performance (1-3 points)
    • Indoor Environmental Quality Credit 2.4: Daylight and Views (1-2 points)
  • Education Resources

    U.S. Green Building Council

  • More Resources

  • PIM Descriptors


    Level: Beginner

    Category List:

    • Envelope

    PIM Attributes:

    Improvement Type:


    • Engineering/Facilities Management
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