You’ve done your research. A few companies have come through the door, and now you’re sitting at the kitchen table with three quotes in front of you. One is noticeably lower than the rest. It’s tempting. After all, it’s the same window, right?
Not always.
When London homeowners compare window quotes, the number on the page is only part of the story. What doesn’t show up in a low quote is often just as important as what does. This guide breaks down why that gap exists, what it can cost you over time, and what questions to ask before you sign anything.
Why Two Quotes for the Same Window Can Be Thousands Apart
Window replacement is not a standardized purchase. Two companies can quote you on the same style of window and land in completely different price ranges because the window itself is only one piece of what you’re actually paying for.
The product, the installation, and the warranty are three separate things. Some companies bundle all of them. Others don’t.
When a quote comes in low, something usually got cut. That might be the quality of the frame materials, the gas fill in the glass unit, or the experience level of who shows up to do the installation. It might also mean the company is using subcontractors rather than trained, in-house technicians. That last point matters more than most homeowners realize, and we’ll get into why.
What Does a Window Quote Actually Include?
A complete window quote should cover all of the following. If any of these are missing or vague, that’s worth asking about before you move forward.
- The product itself, including frame material, glass package, gas fill, and hardware
- A second measurement visit before manufacturing begins
- Custom manufacturing to the exact dimensions of your openings
- Installation by trained, in-house technicians (not subcontractors)
- Interior trim, painted and finished once the window is in
- Cleanup and a full walkthrough of how your new windows operate
- Warranty documentation covering both the product and the installation
A quote that skips or bundles these items loosely is not an apples-to-apples comparison with one that spells them out clearly.
Why Installation Quality Is the Part You Can’t See Until It Goes Wrong
A window is only as good as the installation behind it. You can invest in the best product on the market and still end up with drafts, moisture problems, and failed seals if the installation isn’t done right. And by the time you notice those problems, the damage is often already done.
Here is what tends to go wrong when installation is rushed or handed off to whoever is available.
Measurement Errors
Even a quarter-inch gap between the window frame and the rough opening is enough to create air leaks and, in some cases, void your warranty. Getting measurements right isn’t just about fit. It’s the foundation of everything that follows. At Centennial, we send a trained technician out for a second measurement before manufacturing begins. We believe in measuring twice and cutting once, and that’s exactly what we do.
Poor Sealing and Flashing
Skipping or rushing the sealing process is one of the most common installation mistakes made in this industry. Water gets in behind the frame, works its way into the wall cavity, and mold begins to grow. By the time you can see it from the inside, the repair bill is no longer just a window replacement. It often runs into thousands of dollars, and it’s rarely covered under a warranty that was voided by the improper installation.
No Finishing Work
Proper installation includes painted interior trim, and a full walkthrough of how your new windows operate. If a crew leaves without finishing the job, that’s left for you to deal with. Our installers don’t leave until the trim is painted, you’ve seen the windows in operation, and you have your full warranty and product certification documentation in hand.
Subcontractors vs. In-House Technicians
This is one of the most important questions you can ask any window company. When a company sends subcontractors to your home, accountability gets complicated. If something goes wrong, you may find yourself caught between the company that sold you the window and a separate crew that installed it.
Centennial does not hire subcontractors. Every technician who comes to your home is a trained Centennial employee. That means one company is responsible for every part of your project, from the first measurement to long after installation day.
What a Low Window Quote Might Be Leaving Out
Beyond installation quality, here are a few things that tend to disappear when a quote gets trimmed down.
Warranty Coverage That Actually Holds Up
A lifetime warranty sounds reassuring until you look at the details. Some warranties are pro-rated, meaning coverage decreases over time. Others only cover the product but not the installation. And some require you to deal directly with a third-party manufacturer rather than the company that sold and installed your windows.
Our No Fine Print Warranty covers both the product and the installation for as long as you own your home. No pro-rated terms. No fine print. If something needs attention, you call one number and we take care of it. If you sell your home within 10 years, the warranty can also be transferred to the new owners.
WSIB and Liability Coverage
If a company is sending subcontractors to your home, it’s worth asking whether those workers are covered by WSIB. If they’re not and something happens on your property, you could be left holding the liability. Every Centennial technician is fully covered by WSIB, and we carry a minimum of $5 million in liability insurance on every job site.
Structural Corrections for Older London Homes
Older homes in London often come with surprises once the old window comes out. Rotted framing, missing insulation, water damage that had been hiding behind the original unit for years. Low quotes typically exclude this corrective work entirely, which means you find out about it after you’ve already signed. That can add hundreds of dollars per window to a project that looked affordable on paper.
Energy Performance That Holds Over Time
Not all windows perform equally when Ontario winters arrive. Our replacement windows are ENERGY STAR® certified, which means they’re independently tested and verified to meet Canada’s energy efficiency standards. That matters in London, where freeze-thaw cycles put real stress on window seals and frames every year. A window that fails its seal in year three is not saving you money on heating. It’s costing you more.
You can learn more about our full line of replacement windows on our vinyl windows page.
The Long-Term Math on Window Replacement
Window replacement is a long-term investment. A quality set of windows lasts 20 to 30 years, sometimes longer. When you run the numbers over that timeline, the gap between a quality installation and a cheap one looks very different.
- A failed glass seal costs $200 to $400 per window to repair
- Replacing windows twice because the first set underperformed doubles the cost of what should have been a one-time project
- ENERGY STAR certified windows can meaningfully reduce your heating and cooling costs every year over that same timeline
A quote that saves you $300 per window upfront can easily cost $600 per window within five years if the installation wasn’t done right.
Questions Worth Asking Before You Sign Anything
If you’re comparing window quotes in London right now, these are the questions that separate a thorough quote from a low one. A company with nothing to hide will answer all of them without hesitation.
- Who is doing the installation? Are they employees of the company, or subcontractors?
- What training do the installers have, and are they WSIB covered?
- Does the warranty cover both the product and the installation, or just one?
- Is the warranty pro-rated, or does it remain the same for as long as you own the home?
- What happens if you sell the home within 10 years?
- Who do you call if something goes wrong after installation? Is it the same company that sold you the window?
- Does the quote include a second measurement before manufacturing begins?
- What finishing work is included once the windows are in?
- Are the windows ENERGY STAR certified?
If a company gets vague or pushes back on any of these, that’s telling you something important.
One Company. One Phone Number. One Standard of Accountability.
The Centennial Difference comes down to accountability. We sell, manufacture, install, and service our own windows and doors. You are never handed off to someone else, and you are never dealing with a third party when something needs attention.
We’ve been doing this for 45 years. We’ve completed over 500,000 installations across Ontario, in London, Kitchener, Hamilton, Barrie, Windsor, Niagara, and communities in between. That track record exists because we take responsibility for every step of the process, from the first measurement to long after installation day.
If you’re getting quotes in London and want to understand exactly what you’re comparing, we’re happy to walk you through it. No pressure. No fine print.