What to look for in a Window Warranty

Replacement Window Warranty Factors

When shopping for replacement windows, one of the majors factors that folks consider is the window warranty.  The warranty coverage on your new windows is significant for many reasons, not the least of which is that you want some security in knowing that you will have long term support on a purchase of thousands of dollars. Like many things in the marketplace, window warranties are part real concern, and part sales and marketing. I like to break warranties down to two primary areas: Product Warranty and Installation/Workmanship Warranty.

Product Warranty:

The product warranty on a replacement window is exactly that. It is the length of time that a manufacturer will provide warranty coverage for manufacturer defects. Generally that will not include items such as damage from abuse, failure to maintain, etc.  However, it does provide for replacement parts should anything fail due to a manufacturer defect. Common items include failed glass seals in an insulated glass unit, defective hardware, warpage, etc.  Some manufacturers offer accidental glass breakage as part of their coverage as well. Most vinyl window manufacturers offer a lifetime warranty, while wood windows generally have some variation of a 20/10 warranty, meaning 20 years on glass and 10 years on everything else including the wood.

Things to watch for:

Transferability  is important if you are considering selling the home any time soon. This means that you will be able to transfer the product warranty to one or more future owners of the home. Proration is an often overlooked factor. “Prorated” means that while there is coverage for the entire warranty term, it goes down over time. This is similar to a car battery or roofing shingle, where you have 100% coverage for say the first 10 years, then the coverage starts dropping in increments where you are paying an increasing portion of that as time goes on.  Ideally, a warranty that is fully transferrable and not prorated is best.

What product warranties typically do not cover:

Abuse, acts of God (ie: fires, storms, etc. that would be covered be homeowner’s insurance). Product warranties typically will not cover any labor needed to install the replacements parts. That falls on you as the homeowner, or on the installation company if they offer that service, whether it be paid or at no charge to you. The “fail to maintain” provision can be tricky on wood windows where condensation can damage or rot the wood before the 10 years and potentially be denied as a claim.

Workmanship/Labor/Installation Warranty:

The installation warranty on your replacement windows while important, can vary wildly from one dealer to the next. One company may offer one year on workmanship/installation, while the next offers lifetime, and a third still somewhere in between. The fact of the matter is that most installation related issues will manifest themselves visually within the first year or two after install, so something like a 5 or 10 year warranty is generally adequate. That said, many companies offer 20+ years all the way through lifetime. A lifetime workmanship warranty may sound great in marketing, but remember that the installation warranty is only as good as the company offering it. If all else is equal, certainly a longer term only benefits you as a consumer.

Things to watch for:

Service call/diagnosis charges, coverage to install the parts that are provided under the manufacturer’s warranty and for how long, a list of items that are included or excluded.

What installation warranties typically do not cover:

Installation warranties are intended to cover any poor or defective installation practices. Therefore common things that would be considered maintenance items like caulking, cleaning tracks and such which could hinder operation, etc., are typically not covered or the coverage is limited.


Every window warranty is not created equal. “Lifetime warranty” whether on product or installation may not mean the same thing from one company to the next, so take a look at the details and make sure that you are getting the protection that you are expecting. Also keep in mind that those warranties are only as strong as the companies offering them. Company history and reputation are important tools to look at. Lastly, “Lifetime” does have a quantifiable definition in most states. Here in Wisconsin, “Lifetime” for warranty purposes is defined as 30 years. It is recommended that you determine how this is specifically defined in your own location.

Brandon Erdmann is the owner of HomeSealed Exteriors in Milwaukee, WI.  He’s a window installation expert, a supporter of this site and an all around great guy.  If you’re in the Milwaukee area and you’re thinking about new windows you should give Brandon a ring.  You’ll be glad you did.

Author: HomeSealed Brandon

3rd generation in home improvement industry, specializing in windows and home performance. BPI certified Building Analyst. When not helping folks with window related topics, I enjoy spending time with my wife and six children, and coaching youth sports.

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