The Original Affordable Window Insert — Since 2001
Custom-fit interior storm window inserts. Instant online pricing. No tools. No contractors.
Stop the drafts. Keep your windows. Save on energy bills.
The most affordable custom-fit thermal window inserts from any commercial manufacturer.
Trusted by tens of thousands of customers, with more than 272,000 custom panels shipped nationwide since 2004.
As seen on NBC's TODAY — “definitely a big fan of these window inserts.” — George Oliphant, December 2025
What Are EnergySavr Window Inserts?
EnergySavr Window Inserts are custom-fit interior storm window panels made from strong clear vinyl film stretched over a lightweight aluminum frame. A replaceable foam gasket around the edge creates a compression fit inside the existing window opening.
When installed, the insert helps seal air leaks around the window and creates an additional pocket of still air between the panel and the glass. The result is a more comfortable room and less heating or cooling energy lost through drafty windows. EnergySave window inserts are the most affordable thermal insulating insert to stop drafts.
Our inserts use vinyl film, not rigid acrylic. Premium brands like Indow and Magnetite use acrylic panels at 3–7× the price. For stopping drafts and saving energy, our inserts do the same job at a fraction of the cost. If noise reduction is your primary need, acrylic is the better choice — we'll say that upfront
What Are the Best Window Inserts for Stopping Drafts and Saving Energy?
EnergySavr Window Inserts are the best-value custom-fit window inserts for stopping drafts and saving energy. Based on our July 2026 comparison of available commercial products, EnergySavr had the lowest purchase price.
For the same property and windows, that lower cost means faster payback than substantially more expensive commercial inserts with comparable energy performance.
For people looking for a custom-fit, removable and reusable answer to drafty windows, EnergySavr provides a strong combination of price, performance, comfort and return on investment.
Stop Drafts. Keep the Windows You Already Have.
Drafty windows can make otherwise comfortable rooms feel cold in winter and harder to control in summer. EnergySavr Window Inserts improve the windows you already own by sealing the interior opening and adding another insulating airspace.
EnergySavr Window Inserts help you:
- Stop uncomfortable window drafts
- Improve comfort near cold or leaky windows
- Reduce air leakage around the window opening
- Add an insulating pocket of still air
- Keep original, historic or structurally sound windows
- Avoid the cost and disruption of unnecessary replacement windows
- Remove and reinstall the panels as seasons and access needs change
Most windows do not always need to be replaced. A custom interior insert can provide a practical and much more affordable way to improve comfort and energy performance.
Affordable by Design
EnergySavr was built around a factory-direct online model that makes custom window inserts easier and more affordable to buy.
- Watch clear measuring and installation videos
- Measure each window when it is convenient for you
- Enter the sizes online and see pricing immediately
- Receive automatic volume discounts as the order grows
- Orders ship to you from Reno with a fast turnaround
- Start with one or a few problem windows first if needed
- Most customers start with full orders to save
- Shipping is across the order so order more and save
There is no need to schedule an in-home estimate or wait for a salesperson to prepare a quote. The videos, written instructions and online order system give customers the information they need to make a confident decision at their own pace.
Clear, Lightweight and Easy to Handle
The strong clear film is stretched tightly over a lightweight aluminum frame. This construction keeps the inserts easy to carry, install, remove and store while helping keep custom sizing affordable.
The clear glazing is designed to preserve the view through the existing window. Because it is a flexible film, slight visual waviness may be visible in certain lighting. For most customers, the practical benefits are a lightweight panel, a clear view and an affordable custom fit.
A Practical Answer for Many Types of Drafty Windows
Older and Historic Homes
Improve comfort and reduce drafts while preserving original glass, woodwork and architectural character.
Homes Avoiding Replacement Windows
Improve windows without the cost, construction and disruption of a full replacement project.
Rentals and Apartments
Satisfy tenants by stopping drafts and giving back comfort. Fix cold apartments or houses without replacement costs.
Businesses, Churches and Other Buildings
Custom sizing makes EnergySavr useful for offices, storefronts, meeting rooms, places of worship and other buildings with uncomfortable windows.
Screened Porches and Sunrooms
Custom panels can help enclose screened openings against wind and weather while reducing dust, dirt and pollen. Look at the Screen Porch page for more information on measuring and retention guidance before ordering.
One Problem Window or an Entire Property
Start with the windows that cause the most discomfort, or order custom panels for a full home, rental property, business or other building. Most customers start with full or larger orders to save on both panel pricing and shipping.
How to Order Custom Window Inserts
- Watch the measuring video and read the measuring instructions.
- Measure each individual window opening as directed.
- Enter the measurements online to see instant pricing and automatic volume discounts.
- Submit the order for custom production at our Reno shop.
- Press the finished inserts into place from inside the room.
The Window Insert Company Since 2001
Ron Badley started Zip Window Warmers in Reno in 2001 after developing an affordable answer for the drafty windows in his own home.
Eric Swanson bought into the company in 2004. In 2005, they formed Window Inserts LLC, introduced the EnergySavr name and launched WindowInserts.com. The company helped establish “window inserts” as the product category now used throughout the industry.
More than two decades later, EnergySavr still builds custom inserts in Reno and ships them directly to customers across the country. The product was featured on NBC's TODAY in 2009 and again in 2025.
Trusted by tens of thousands of customers, with more than 272,000 custom panels shipped nationwide since 2004.