Indow Windows: The Missing Piece To The Passive House Puzzle

Solving A 100 Year Old Problem

When Joe Giampietro - a Seattle resident and prominent Passive House architect decided to finish converting his 100+ year old house into a Passive House build, the windows were the final missing piece of the puzzle.

"Our house has been very leaky and uncomfortable. The blower door test was off the charts, largely because it was unsealed." Joe told us.

Investing in 10, high-grade, triple pane windows would have catapulted his project cost into the tens of thousands of dollars. Luckily, Joe discovered that IndowPRO - the newest product from leading window insert manufacturer, Indow Windows - was the perfect solution to meet his thermal insulation needs at a fraction of the cost.

Joe was also concerned with the risk of condensation and air tightness. "I need to ensure the interior panel was tight enough to keep any water vapor open to the exterior."

IndowPRO: The Evolution of Secondary Glazing

With a U-Value of 0.075, air infiltration of under 0.05 CFM using high-quality VIGs, and a simple, same-day installation process, IndowPRO checked all the boxes.

IndowPRO is a revolutionary new design that allows building owners to add virtually any type of secondary glazing to their existing windows with minimal cost, time, or disruption.

Designed to work with a wide variety of glazings from high-grade acrylic to vacuum-insulated glass, IndowPRO creates a thermal (and acoustic) barrier on par or better than even the highest-grade triple pane windows. The system installs in minutes with minimal hardware and the cosmetic cladding can be customized to your color specifications to ensure the frame blends in seamlessly with your windows.

The best part? IndowPRO is 1/10 the cost of comparable full window replacements.

The Perfect Fit

When Joe discovered he could accomplish his Passive House goals, keep his original 100 year-old windows intact, and avoid a costly investment in window replacements, the choice was obvious. Indow manufactured the IndowPRO framing to Joe's exact window measurements and worked with LuxWall to arrange installation with their Enthermal™ vacuum-insulated glass. The complete installation process took just 24 minutes per window with just a single contractor - who was installing IndowPRO for the first time.

The result? “Like a wall”.

The difference was immediate. A thermal reading taken shortly after installation compared the IndowPRO-fitted windows to the fully insulated wall next to them showed only a 0.5° F difference. Despite the windows barely looking any different than before, they were now thermally sealed to the exacting standards of Passive House principles.

“They are almost invisible. The width of the cladding matches the original sash, so it’s not obvious there’s something there.”

Joe couldn’t be any more thrilled and thinks IndowPRO is a fantastic option for Passive House retrofits.

“If I was helping someone remodel a house, and their windows were in good shape, I’d recommend using IndowPRO.”

A Massive Opportunity

It didn’t take Joe long to realize how IndowPRO could help solve grid decarbonization and make high-performance retrofits feasible for the millions of buildings with drafty windows.

There is a huge opportunity, because buildings consume 30 to 40% of energy and improving the energy efficiency of existing windows is always the key question. The fact that it goes in quickly is the huge delta. It’s a no-brainer, from the cost of the product to the installation process.

— Joe Giampietro
Phius certified Passive House consultant

Project designers are often challenged to improve energy efficiency and meet client demands for comfort and quiet, while preserving building aesthetics. IndowPRO is engineered to solve the most difficult part of retrofits: logistics and installation.

Frames ship knocked-down for easy site logistics and are designed to ensure a reliable, airtight fit even in out-of-square openings. The Indow system dramatically reduces measurement errors, installation delays, and costly callbacks.