In your search for window solutions for your home, you may have come across the word “retrofit.” When it comes to windows, “retrofit” has a couple definitions. Retrofitting windows can refer to replacement of the window sash, the part of the window that holds the glass and usually slides up and down or side to side. Retrofitting a window can also refer to fitting an existing window with an attachment, such as an exterior storm window or interior storm window insert. In either case, the window frame will stay in place and not be altered.

While the idea behind both types of retrofitting is to preserve as much of the original window as possible, the two options do have fundamental differences that should be discussed before you decide which is best for your windows.

 
Category Retrofit Replacement Retrofit Attachment
Cost X Better
Energy Performance Good Better
Sound Reduction Good Better
Ease of Installation X Better
Eco-Friendliness X Better

Retrofit Replacement vs. Retrofit Attachment: Cost

On average, retrofit attachments, such as interior storm window inserts, are 75% cheaper than wood window retrofit replacements, and 50% cheaper than vinyl retrofit replacements. According to Remodeling, 2021 costs for a wood window replacement project was $23,219, and a vinyl window replacement project was $19,385. This was for 10 vinyl 3×5’ windows. A similar project for retrofit attachments like Standard Grade Indow window inserts would cost $4,500. If you consider the fact that the lifespan of replacement windows is around 15 years and Indow window inserts come with a lifetime warranty, that price difference will increase over time.

 
Cost comparison of 19 replacement windows vs. 19 window inserts: $8,000 and $25,000, respectively

Retrofit Replacement vs. Retrofit Attachment: Energy Performance

Retrofit attachments have the advantage of improving the mean radiant room temperature of a space. Interior storm window inserts often use acrylic for their panels, as opposed to glass exterior storm windows. Acrylic does a better job than glass of slowing heat transfer, which helps them maintain a higher mean radiant room temperature.

A year-long pilot study by Portland State University in several homes showed that the impact of this warmer surface temperature of acrylic panels allowed thermostats to be set at a lower temperature during winter months, while occupants remained comfortable.

 

Retrofit Replacement vs. Retrofit Attachment: Noise Performance

Retrofit window attachments can reduce outside noise by 70% (18.9 dBA) when added to single-pane and 50% (10-12 dBA) when added to double-pane windows. Retrofit replacement windows typically reduce outside noise by about  25%. There are retrofit replacements optimized for sound reduction, but they are priced higher than standard replacements.

 
Man installing Indow window inserts. Retrofitting windows with Acoustic Grade inserts reduces noise.

Retrofit Replacement vs. Retrofit Attachment: Ease of installation

Retrofit replacements should be installed by a contractor, though advanced DIY homeowners can find plenty of window sash replacement how to videos online.

 
 

Because houses shift over time, 95% of window openings are not completely square. For this reason, we recommend DIY sash replacement projects to only the most seasoned DIYers.

Interior retrofit attachments have a very straightforward installation process. Most are custom-fit for your window. Indow window inserts use a patented silicone compression tube that allows for a snug fit in your window frame. Installation is as simple as pressing the insert into the window frame and making minor adjustments to the silicone edge to get a perfect fit.

Windows torn out for replacement. Consider ecological impact with retrofit vs. replacement windows.
 

Retrofit Replacement vs. Retrofit Attachment: Eco-Friendliness

Vinyl windows are the more common type of retrofit replacement window. Vinyl windows have some shocking impacts on our environment. Vinyl windows produce 43% more waste than timber windows. Once vinyl windows have met their life expectancy of around 15 years and are replaced, only 3% are recycled.

Indow window inserts have been lab tested and can withstand replacement and re-installation up to 6,000 times. These inserts are a long-term solution for your windows, and ensure that they will not see a landfill. Indow is proud to work with local recyclers within Portland for our leftover acrylic materials. We also donate leftover materials to organizations that upcycle scraps for artistic purposes. 

So there you have it on retrofit replacement windows vs. retrofit window attachments. Ready to learn more about acrylic attachment options vs. glass? Check out our Why We Use Acrylic vs. Glass blog post.