Third Party Research and Performance Data

Multiple studies have been carried out by third-party sources testing the efficiency of Indow window inserts across a range of categories. Indow inserts have multiple functions and capabilities depending on the grade type – read the results and see the performance data of all grade types here.

Drafts & Savings

Window insert performance.

Two independent studies carried out by the U.S. Department of Energy and Portland State University's Green Building Research Laboratory found reductions of 20% to energy consumption when using Indow window inserts, significant savings that allow for lower heating and cooling bills.

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Window insert performance.

Indow window inserts reduce outside noise penetration by up to 70%. This was tested in a study conducted by the British Columbia Institute for Technology, as well as by Portland State University's Green Building Research Laboratory. Be it over single or double-pane windows, Indow inserts are proven to dramatically reduce noise.

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Lights & UV

The sun shines bright overhead on a beautiful day.

Each of our specialty grade types which provide ways to block sunlight from windows is made from a unique high-quality acrylic or medium-density hardwood fiberboard, lined with our patented silicone compression fit tubing. From light transmittance to UV blocking, get the performance data for our Light & UV grade types here.

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Indow is dedicated to continuous improvement and innovation. That’s why we continue to test all of our products with the latest technology available. This continuous testing is important to us because it ensures we are still the best product possible for blocking noise, creating comfort, and saving you money. You can read updates about our latest testing on our blog or wait for us to update test results here.

At Indow, we have a triple bottom line which includes creating more products that are more affordable for more people. That takes rounds and rounds of testing to ensure that our new product will perform as well as our first. You can watch the kinds of tests we perform here.

Consumer Reports & Industry Testing

A 2019 report on secondary window attachments concluded that window inserts benefit all types of spaces, specifically by increasing their efficiency and reducing cost. The Commercial Window Attachments report was compiled by Northwest Energy Efficiency Alliance (NEEA) and Evergreen Economics to understand the current market of secondary windows, their costs, how they fit with code, and their performance.

To perform their study, NEEA and Evergreen Economics interviewed architects, building owners, general contractors, energy services companies and other industry experts. They used three case studies to prove the benefits, including 2 which featured Indow window inserts. Indow was not contacted during this study.

Indow is AERC certified. AERC, the Attachments Energy Rating Council, is an unaffiliated organization that rates window attachment products on energy efficiency by measuring various factors such as Air Leakage (AL) and U-Factor.

On air leakage, Indow scored in the top two out of 33 storm windows tested, 11 of which were interior storm windows. U-Factor is an indicator of heat transfer through a surface. It tells you how well a window product insulates. Indow inserts have a U-Factor of .3, making them a top performer on insulation among all available storm windows.

If you’d like to test Indow inserts in your commercial space, use our Pilot Program. Architects interested in a sample kit or CSI specs visit our window preservation inserts page.

Window Insert Testing by Field Experts

Other than submitting our products for testing in official laboratories, we have several professionals and experts in their field who have tested Indow inserts in their own labs and warehouses:

Scott Sidler runs his own historic restoration company, has worked with windows for decades, and calls The Craftsman Blog his “laboratory, classroom, playground, and favorite place to be”. His video of Indow noise blocking performance is a great resource of an expert opinion

Riffs, Beards & Gear is a musician who does audio gear reviews. He got Indow window inserts for his home recording studio. He did an unboxing, installation, and review video.

One professor and Indow customer used his thermal imaging camera to capture the difference in temperature his Indow inserts made.

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