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Every historic building or commercial project has unique window shapes and configurations. SLIPs are built to exacting standards for professionals working with precise measurements, drawings, or as-built conditions.
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(!) SLIPâ„¢ systems are custom-made and ship in large crates. Due to the cost of shipping, order minimums are required.
HOW TO MEASURE FOR INSULATING WINDOW PANELS
Measure for “Daylight Size”
Our SLIP systems are fabricated to match each window opening and are installed by your project team — not homeowners. With measurements taken by your contractor or consultant, we ensure a professional fit and finish every time.
See Details
The precise measurement we need is what we call “daylight size,” meaning it’s measuring from where the glass meets the wood on one edge to the other vertically and horizontally. The total size of finished Window SLIPs will be large enough to account for the SLIP aluminum size as well as the sealant to maintain all of the natural light from before.
The first measurement you provide should be width, followed by height for each window pane. For double-hung windows, the process needs to be repeated for both top and bottom sashes because they are not always the same size.
How Do We Price Our Window SLIPs?
Our Window SLIPs are priced by the square foot, material cost, and shape. We offer three glass types for our SLIPs: Clear Tempered, Pilkington Energy Advantage™ low-emissivity (low-e) glass, and Guardian SatinDeco® acid-etched translucent glass.
Clear Tempered Glass
- Excellent clarity of the glass ensures true colors are seen and optimum vision quality is achieved when looking through the layers of glass.
- These panes of glass have a high level of light transmittance.
- It allows maximum natural light to cascade in, to create pleasant interior rooms.
Low-E Glass
- Coated low-emissivity glass panes offer additional thermal insulation.
- Its high solar heat gain allows a high level of solar energy to enter.
- Customers enjoy warmer and brighter interiors and reduced heating and lighting costs compared with regular glass.
Acid-Etched Translucent Glass
- Guardian SatinDeco® acid-etched translucent glass is ideal for both interior and exterior applications.
- The smooth finish obscures the view through the glass while allowing natural light to come through.
- The uniform surface is robust and durable, helping prevent marks from grease or dirt.
- This glass is an excellent choice for bathroom window privacy, and depending on the size of the window, it will let in excellent light.

Your Quote is Approved What Comes Next?
Once your quote is approved, we’ll move to fabrication. SLIPs ship in custom crates. Your shipment includes everything your contractor needs: pre-sized components, hardware, sealants, and installation guides. For more complex installs, our techs can consult or assist onsite, depending on project location.
Frequently Asked Questions
After the Quote is Approved, How Long Does it Take to Ship My Order?
Once we enter production, it takes 8-10 weeks to deliver your Window SLIP system. We pride ourselves on exceptional customer service. If you have a specific deadline you need to meet, contact us to discuss your options.
We work with both residential window applications and commercial projects. Depending on the size and scale of your project, we may need extra time to fabricate each SLIP. Contact us if you have an extra-large project, curved windows, or need custom painting for your order.
Where Are Your Window SLIPS Manufactured and Assembled?
Our products are manufactured in the United States and assembled in our Oregon Workshop.
How Do I Measure Windows for the SLIPs?
We need measurements for each window in what we call “daylight size,” measuring from where the glass panel meets the wood from side to side and top to bottom. For more detailed information on how to measure for window SLIPs, read the detailed instructions here or watch this video.
What Materials Are Used in the Panels?
Are Window SLIPs EnergyStar Certified?
We’re so confident in our Slim Line Insulating Panels that we put them to the test. We worked with Intertek laboratory to conduct testing, and they concluded that single pane windows with a SLIP have a U-Factor that is on par with EnergyStar Certification guidelines. Read the full report here.
Our customers not only experience greater energy efficiency, but also report noise reduction, improved functionality and structural integrity for their windows, and better-controlled indoor temperatures throughout their home.
How Much Money Can I Save with Insulated Windows?
Our customers see as much as a 72% reduction in their energy bill after installing SLIPs. In addition to the significant energy savings, our customers save money on costly seasonal solutions like storm windows or weatherstripping and enjoy double-pane quality insulation without the cost of full window replacement. This makes them the ideal solution for drafty, older windows that need modern functionality. Keeping sunlight but reducing the sun’s heat that makes it into your home is an ideal improvement for the summer months as well.
Why Choose Us
With decades of experience in window installation, repair, and refurbishment, we’re the experts. We created Window SLIPs to provide the insulation of double-pane window units at a lower cost. Owning a historic home doesn’t mean you have to live with energy loss. In both residential and commercial buildings, we have seen big improvements with SLIPs reducing heat transfer. If you want your home cooler in the summer, warmer in the winter, and more efficient year-round, SLIPs are for you!
Send Your Measurements, We’ll Provide an Insulating Window Panel Quote
We work to make buying and installing custom SLIPs as easy as possible. Once you provide us with measurements for your project, we’ll get to work crunching the numbers in a free quote. If it looks good, we’ll head right into production and have SLIPs on your doorstep in 8 to 10 weeks. Considering replacement windows would take twice as long for at least double the price, we’re confident SLIP is the right choice for budget-conscious and time-sensitive projects.