Should I restore or replace my windows?

By Matt Risinger


Choosing to repair or replace windows is a hot topic for homeowners, partly because there is so much misinformation. Ads for window replacement companies tend to use highly overrated numbers, for example, as to what you might save on energy by replacing windows. Some claim as high as 30% to 50% savings on energy bills—and my experience is that those numbers are inaccurate. The numbers are much lower, closer to between 5% and 15% savings. It's also essential that the decision not rest entirely on energy saving—the comfort you experience living in your home should ultimately be the goal.

Matt Risinger discusses the reasons behind replacing versus repairing windows.

Let's look at both restoration and replacement and why you would select one versus the other.

Window Restoration

Often, homeowners and builders look to window replacement as the first option to improve energy efficiency, and it might not actually be the best first option.

Of course, your windows could be leaking air. Even if you have a 75-year-old double-pane window, you may be surprised that you can do a pretty good job of tightening it. It’s possible to put new brass weatherstripping throughout the window and sometimes even new hardware that dramatically reduces leakage.

Through the years, I've made several videos on this particular topic. One option is to pull the old window, repair it, and use PROSOCO’s R-Guard fluid-applied products, including FastFlash, which sticks to just about every building material on site including wood frame, plywood, shiplap, metal flashing and even tar paper and other varieties of old-school flashings.

"It may not be the window that's at fault. Many structures leak air, water, and energy through the building envelope."
"It may not be the window that's at fault. Many structures leak air, water, and energy through the building envelope."

PROSOCO’s AirDam is used for a four-sided air and water seal between the four sides of the window frame. In this case, use a backer rod and either spray foam or some insulation to get your best insulation value. The backer rods are essential when filling that gap to ensure that AirDam is only sticking to the window itself into the jamb. AirDam is highly flexible, but you just want it to adhere on the right- and left-hand sides, where the window jamb meets the rough opening.

AirDam also has excellent adhesion to modern house wraps and is a good solution for adhering the house wrap to FastFlash when a fail-safe transition is required to provide continuity of the air barrier.

FastFlash is a fluid-applied membrane to waterproof around rough openings of doors and windows -- perfect for retrofit applications and new builds.

Another tool in the PROSOCO toolbox is its Joint & Seam Filler to fill cracks, pinholes, and gaps and provide continuous support of fluid-applied flashing membranes, waterproofing, or air barrier components.

A reasonable approach is to consider restoration before replacement—considering everything before choosing.


Choosing a replacement should depend solely on where the problem is and its severity. For example, if the window glass, sashes, or frames are damaged, worn, or ineffectual, that could signify that you need new windows.

Quality windows today are expected to last between 15 and 30 years. Vinyl windows typically provide a 20-25-year warranty, which is, for all purposes, their natural lifetime.

Windows are a functional update that can be an important factor when selling a home. Spending $10,000 on new windows can raise the asking price on a house by approximately $8,500, according to ISoldMyHouse, netting an 85% ROI.

So, How Do I Choose?

The choice can be out of your hands in certain circumstances. Repair isn't always possible, for example, with most modern windows. Double- and triple-pane sealed windows are complex and, in some cases, impossible to repair.


Matt Risinger demonstrates how to replace windows the right way with FastFlash.

Repairable items would be cracked or broken glass (replace sash), broken muntins/mullions for single-pane windows, tuck window sashes, exterior drip cap, exterior window casing, and minor water leaks.

Typically replacement is used for foggy windows caused by water condensing inside the window's double-paned or triple-paned insulated glass unit (IGU), structural problems, and significant water leaks.

The Window May Not be that Culprit

It may not be the window that's at fault. Many structures leak air, water, and energy through the building envelope. Given that leaks are often discovered around windows—they are seen as the culprit, and homeowners automatically go to replacement for the fix. However, performance testing and investigation can indicate minimally invasive repairs that dramatically improve the performance of existing windows.

It's a tough choice. Since cost is generally the basis for the choice, buying new windows for an entire house can end up costing several thousand dollars. It's an excellent decision to dig further – what is the real problem, and what would be the best outcome?


Air & Water Barriers

Meet the Passive House criteria for energy efficiency

By Jake Bruton, Aarow Building When builders consider energy efficiency, one standard is at the top of the list. The Passive House standard establishes such criteria as space heating and cooling demand, renewable primary energy demand, airtightness, and thermal comfort. These are achieved through five Passive House principles: thermal bridge-free[…]

Air & Water Barriers

The Accidental Passive House

A 260,000+ square-foot high school in Washington is performing at Passive House levels of energy efficiency -- despite the owner never having aspired for it to do so. Passive House was not a stated goal for the architect and owner of Sehome High School in Bellingham, Wash., but the choice[…]

Air & Water Barriers

How to spray Cat 5 air barrier on CMU

The top 5 things you need to know to get an airtight envelope with this common building material.   CMU (concrete masonry units), also called architectural block, is one of the most common building materials used in construction due to its versatility and durability. A sprayable, fluid-applied air barrier coating[…]

Concrete Flooring

A Living Building “first” in Santa Monica

Smart strategies for material reductions led the project team of the City Hall East building in Southern California to choose finished concrete floors.   Adding onto an existing, municipal building registered as a historic landmark didn’t intimidate the project team of the Santa Monica City Hall East (formerly called the[…]

Hard Surface Care

A half dozen ways to winterize that you probably haven’t thought of before

When we hear "winterize," we might think of battening down the proverbial interior hatches and making sure inclement weather doesn't have a chance to intrude on our cozy winter existence. We replace furnace filters, turn off outside hoses and in colder climates, drain them, we check our furnace, schedule our[…]

Karuna House R-Guard application

Air & Water Barriers

In pursuit of Passive

Part of PROSOCO's Guide to Blower Door Testing BLOWER-DOOR TEST PASSED ON ATTEMPT #1 Rainy weather was rendered a non-factor for Oregon’s Karuna House, causing zero delays as the crew used a fluid-applied air barrier on damp plywood. The air barrier installation on this Passive House residential project went faster[…]

Palm trees in hurricane

Air & Water Barriers

The case for FastFlash and Passive Houses

When we introduced the PROSOCO R-Guard FastFlash air and waterproof barrier system, we knew a big market would be in coastal areas subject to tropical storms and hurricanes. That's because FastFlash is tested and proven to stop air and water leaks through building envelopes in conditions up to and exceeding[…]



The Bullitt Center and the transformation of building materials

The six-story, 50,000 square foot Bullitt Center is seeking to change how buildings are designed, built and operated. Its goal: to shift the benchmarks significantly forward for long-term environmental performance and energy efficiency, renewable energy and other green building technologies. Seattle's Bullitt Center seeks to be a "living building" --[…]

Renaissance Condominiums-FastFlash-case-study

Air & Water Barriers

How to build durable buildings (a FastFlash case study)

FastFlash proves durable performance over 10 years. A lot can happen to a building over 10 years. Weather happens. Leaks happen. In worst-case scenarios, some newly constructed structures even need to be demolished after 10 years (or fewer) due to poorly designed and installed building products. At PROSOCO, we've long[…]

Air & Water Barriers

Outside the studio

When Dan Rockhill was a young boy, he'd go down to the local tire shop to get an inner tube to take to the shore. He and his peers understood the connection - that inner tube of the tire also happened to serve as a superior floating device. Today, kids[…]

Matt Risinger

Air & Water Barriers

How to replace windows the right way

Our friend Matt Risinger, blogger and YouTuber of all things building science, has created this really helpful video on how to replace windows the right way.   At this residential site near Dallas, Texas, he uses the following R-Guard products: FastFlash for the rough openings Joint & Seam Filler to fill cracks,[…]

Green building

Profiles in Building Longevity: Jonathan Wright

Jonathan Wright spoke clearly and succinctly to a crowd gathered in a sparkling new building on the campus of Hampshire College. He recounted the first time he had visited the school. “A 16-year-old boy arrived at what was not yet a campus of what was not yet a college,” Wright[…]

Construction on Kiawah Island

Air & Water Barriers

A better building envelope to stand up to the most extreme everything

Charleston, S.C., is an amalgamation of virtually all kinds of extreme weather and construction challenges. Charleston, S.C. is a popular place, both to live and vacation, due to its abundance of history, charm and fabulous weather. As the city continues to grow (it just overtook Columbia as the largest city[…]