If you own or manage a building, you know that reducing energy bill can drive greater tenant retention and translate to healthier bottom line. According to the US Department of Energy and a recent study published by CONSOL Energy, 3M Window Films can reduce energy usage up to 19 kwh per sq ft of windows. With typical ROI's of less than three years, building owners and managers have discovered the cost savings associated with 3M Window Films. In fact, with utility rebates, authorised 3M Window Film dealers have completed projects yielding payback in as little as one year.
Energy consultants are also pressed to look for cost-effective energy saving technologies, like 3M Window Films.
Get in touch with our New Zealand Silver, Gold, and Platinum 3M™ Select Installers who are ready to help you find your window film solutions, work on the installations, and answer your questions. You can also speak to our 3M Technical Support for other concerns.
Security, solar and decorative window films can change your view of what window films can do. Solar and tinted window films save valuable energy and increase worker comfort. Security and safety window films provide shatter-resistant protection in severe weather and bomb blasts. Decorative window films add privacy and style within your building. Now you can provide sun control, UV protection, window tinting and privacy while increasing energy savings. 3M™ Window Films help improve tenant comfort, reduce hot spots and increase window safety in buildings.
Window film is designed to save energy in much the same manner as a window. In fact, window films are certified by the NFRC (National Fenestration Rating Council), the same organization that certifies the performance values of a window. Windows and window films have 3 key specifications that correlate to the amount of energy that a building uses, Visible Light Transmission (VLT), Solar Heat Gain Coefficient (SHGC) and U value. 3M™ Window Films are designed to upgrade existing windows at a fraction of the cost of replacing the windows, by helping to reduce the SHGC & U value.
The SHGC measures the amount of solar radiation that passes through the window. An SHGC of 1.0 would suggest 100% of the solar radiation comes into the building, and an SHGC of 0.25 would suggest that 25% of the solar radiation comes into the building. Nearly half of all the energy that comes from the sun is visible light, so while lower SHGC’s may reduce the amount of solar energy entering the building, there is a trade-off between the darkness of the window and the SHGC. It is important to note that Low E windows are often thought of as high performance, but by definition, a Low E window is intended to reduce the U value. If you have a Low E window, this does not necessarily mean you have a low SHGC window.
The U value is the measure of the rate of heat transfer through a window due to conduction or convection. Reducing the U value is often completed by going from a single pane to a double pane window or by adding a Low E coating. The U value helps save energy when there is a temperature difference between the inside and the outside of the building. In general, reducing the U value is more beneficial in cold climates.
VLT is the amount of visible light that transmits through a window, so the lower the number the darker the window. In many commercial buildings today, lights are turned on at the beginning of the work day, and off at the end of the work day, regardless of how much natural light penetrates the window. Therefore, VLT is not often considered when determining energy savings potential of a window or window film.
For larger more sophisticated projects it is recommended to leverage hourly analysis energy simulation software. This is the typical methodology recommended for any building envelope upgrade, as the modifications to the building envelope affect many building systems. In addition, simple Excel based calculations typically do not take into account how the window performance changes as the angle of the sun changes. To do these calculations, you have two options. 3M will work with you to provide an hourly analysis model free of charge, or 3M can help enter the performance of our films into your preferred energy simulation system.
About 3M’s calculations:
3M utilises the US DOE recommended EnergyPlus™ algorithm to calculate potential energy savings. The output report is generated using a Graphical User Interface (GUI) to EnergyPlus called EFilm, but all calculations are completed by the EnergyPlus Algorithm. We recommend EnergyPlus as it can be audited by 3rd parties, including utility companies and rebate auditing firms.
Utility companies have been incentivising 3M Window Films for years, either through prescriptive or performance based incentives. In some cases, utilities have paid as much as 40% of the project costs.
Contact 3M and schedule an audit for your building today.