What Windows Installation Is Really Like

Installing new windows can feel like a daunting project. You want to know how to prepare, what the process entails, and how much of your life will be disrupted before you can get back to enjoying your home—and your new windows. I spent a full day shadowing installers from Renewal by Andersen, which made our list of best replacement window companies, to get these answers and more.

This article summarizes my observations from watching a crew in St. Louis, Missouri, perform various window jobs. I also share insights compiled from my notes, interviews with the team, and overall experience.

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Before the Installation

A homeowner must undergo a consultation before setting an installation day. Some companies offer virtual consultations, but installers recommend an in-person consult to get the most accurate, thorough assessment.

The consultation is a time for your window installation company to learn about your vision and requirements for the project, as well as for you to ask questions. Renewal by Andersen recommends that homeowners also use this time to set expectations they want the crew to adhere to, such as navigating around pets during the installation. 

The Renewal by Andersen installers I spoke to encouraged homeowners to vet companies during this stage by asking about lead certifications, as window contractors must update theirs every five years. Additionally, homeowners should ask how the company trains its installers. The Renewal by Andersen crew told me that on-the-job training is common and produces the best technicians. 

I learned that detailed measuring is one of the most important parts of the consultation. This step can take one to two hours to ensure it’s done correctly. Renewal by Andersen told me that technicians can now use augmented reality during the consultation to give you a rough idea of what a particular window design and style will look like in your home.

Homeowners who choose to proceed with the project after the consultation will receive a packet of information, including their estimated cost, the company’s warranty information, and other relevant details, such as measurements and hardware features. If you want more time to make a decision, you’ll receive a baseline quote but other details may be limited. 

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Day of Installation

Installations typically start early in the morning, at 7:30 a.m. or 9 a.m. My day began at 7:30 a.m because we had to pick up boxed windows from a distribution center before going to the jobsite. A crew typically installs 8–10 windows per day. I watched Renewal by Andersen install five windows at one house. However, one window was a large sliding window that replaced three full-frame windows, so technically I observed seven windows being replaced.

Here are some key things I noticed during the installation:

• The installation crew began by laying down runners throughout areas of the home they would be frequently walking through. This helped keep the home clean and prevented floor damage. Installers also placed bins around each window site to streamline cleanup and keep the area free of debris. I noticed a few screws fall here and there during more intensive parts of the job, but I was told that they go back and check for these during cleanup.
• The homeowner needed to move their car from the garage to the street so the new windows and other tools could be stored there. The installers also used the garage to cut wood. They parked their trailer in the driveway for easy access, as it held most of their supplies.
• I noticed that the crew attempted to protect the homeowner’s shrubs and bushes that were close to the windows by covering them with tarps. This worked well, but I could see the landscaping getting damaged if any mishaps occurred, such as scaffolding falling or heavy tools being dropped.

How Insert Windows Are Replaced

I observed the team replacing both insert and full-frame windows. An insert window is installed within the existing window frame rather than replacing the entire structure and casing. Insert windows are cheaper and quicker to install, but they’re slightly less insulated than full-frame options. Here are the steps that Renewal by Andersen followed to replace the insert windows during my visit:

1. The installers began by walking through the home, placing runners in high-traffic areas, and remeasuring the windows. Then, they relocated or covered any furniture near the windows.
2. The installers removed the sealant as well as the old windows and their parts, such as screens and frames. They used a drill and hammer, which caused moderate noise.
3. The crew cleaned up the surrounding area with a shop vacuum, which also caused moderate noise.
4. The team placed the new windows into the empty frames, then leveled them using spacers and shims. Installers drilled crucial parts of the windows into place. The windows could sit in the space at this point, but there were still gaps to fill in. 
5. The crew measured the spaces for whatever material was being used to surround the windows, such as metal or vinyl. In this case, the team used Renewal by Andersen’s Fibrex materials.
6. Next, the installers added fiberglass insulation around the windows’ gaps. 
7. Adfoam, a type of polyurethane foam, was added around the windows. 
8. The team cut the window flashing on-site. They cut sheet metal in their trailer and in some areas of the jobsite, such as the garage. 
9. The flashing was added, and the surrounding areas were caulked and cleaned.

How Full-Frame Windows Are Replaced

A full-frame window is a complete unit, including the glass, sashes, frame, and exterior casing or trim. The Renewal by Andersen crew informed me that full-frame windows are typically found in older homes, as the industry favors insert windows. However, a full-frame window can also be converted into an insert window for future replacements. 

Here are the steps that Renewal by Andersen used to replace full-frame windows during my visit:

1. The team had already prepped the home, but if they were starting fresh, they would follow the same initial steps as they did for insert windows, including placing runners and relocating nearby furniture. 
2. Unlike with inserts, the crew needed to remove the entire window and frame by cutting back to the framing studs with a saw. This step caused substantially more noise than the drills used to unscrew insert windows. It can also be considerably more messy depending on how the window opening is set up. 
3. Next, the team used a saw to cut the old windows’ jambs off. Both sawing steps were incredibly loud, especially as the saw got closer to the home’s framing. 
4. A shop vacuum was used to clean up the surrounding area. 
5. Wood pieces cut on-site were nailed into place for the new windows. This step was very noisy, but it occurred inside the garage or on the driveway. The hammering during the second part of this step also produced a fair amount of noise. 
6. Once the wood was in place, the team followed many of the same steps as they did when installing insert windows. The new windows were drilled into the openings with some remaining gaps.
7. Fiberglass was added for insulation, and the same polyurethane foam was added around the windows.
8. Flashing was measured and cut on-site before being added. 
9. The new windows were caulked and cleaned.

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After the Installation

I didn’t see the end of the installation because the team was scheduled to install 12 windows at the home we visited. The team completed eight windows that day and planned to return the next day to complete the job. They informed me that they invite the homeowner to walk through the home once the installation is complete. They showcase the new windows, test their functionality, and ask if the homeowner notices anything wrong or has any questions or concerns. 

The Renewal by Andersen crew also told me that cleanup should be fairly simple because it occurs throughout the installation. The installers double-check each window opening for debris that was missed, and remove any sawdust and waste in the garage or driveway. 

I asked the Renewal by Andersen team how homeowners should care for their new windows following installation. The crew told me that the best thing to do is clean your windows at least twice per year. They recommended using a soft, lint-free cloth plus soap and water. They advised avoiding abrasive cleaners, which typically come as a powder you need to apply and scrub off the window.

Homeowners should also ensure drainage holes remain clear of dirt and debris and inspect window seals and caulking around the windows annually. You typically only need to re-caulk windows every five to 10 years, and it’s fairly easy to do. Caulk degrades over time and becomes brittle, so replacement is routine.

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Do I Really Need a Windows Installer?

Replacing windows, especially insert windows, seems easy enough that you could save money by doing it yourself. However, one thing that stood out during my visit was how many variables can quickly complicate the project. 

For example, we discussed the trouble with mismeasuring windows. ​​Replacement requires measuring windows down 3/8 of an inch from the original opening. The Renewal by Andersen team told me that seasoned installers can fix a mismeasurement as long as it’s within an inch of the needed size, but otherwise, it’s best to simply reorder the windows. This could create a huge headache and cost you money if you attempt the project yourself and measure your windows incorrectly.

Additionally, you may not be able to catch certain issues before starting the project that a professional can spot and handle quickly. The installers mentioned wood rot and framing as two unforeseen issues homeowners frequently encounter. 

Ultimately, it’s possible to replace one or two windows yourself, but professional installation is always recommended, especially for large or complex projects. A professional has the expertise and knowledge to spot and resolve issues, rather than you removing your window, finding wood rot, and not knowing how to proceed. A professional will also be able to complete the job faster and ensure a proper fit.

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Learn More About Replacement Windows

This article outlines the basics of a standard window installation based on my visit to a Renewal by Andersen jobsite, but there’s much more to know. I suggest reading our guide to the best window brands and familiarizing yourself with common window types to determine what windows you might need. Feel free to use the tool below to kickstart the consultation process if you feel confident about what you need for your project.

You can also learn more about Renewal by Andersen in our review or use the tool below to contact the company quickly.

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