GTS Windows & Doors - For Home, For Life - Window & Door Installer in Kitchener, ON

Customer reviews

This business has 27 Google reviews. We show up to five of them below - read the full listing on Google before deciding.

tammy grischow

Sep 23, 2025

Jacob and yanic did an exceptional job here at my place today installing new doors. Extremely polite and kind and kept the place clean and extremely well done thank you for the excellent service !

SheIsBane

Sep 9, 2025

Absolutely fantastic work; quick, clean and a friendly presence. These guys got the job done in a flash, and it really didn't feel like I had strangers in my home. My balcony doors look beautiful and I couldn't be happier! Thank you so much! 10/10 would recommend!

Summer Mccauley

Sep 8, 2025

Amazing service, very quick installing my balcony doors. Provided an amazing upgraded sliding doors for me today! Also amazing customer service, we had a great conversation while they were working :)

mzke elliott

Aug 8, 2025

We spoke with Steven a few weeks ago about having our windows replaced. He was very quick to come by to assess our needs and make a list of suggestions, followed by texts to set up the installation appointment. The two young men who arrived promptly on installation day, Jacob and Yannick, were friendly, fast, professional and delightful to have around. We're so pleased with the windows, workmanship, clean-up and the people we met through GTS. Thanks so much!

Vlad Radenovic

Jun 28, 2022

We recently had GTS Windows and Doors cut out our old window and brick and install beautiful French doors, and we couldn't be happier with the final result. The work was done with care and an attention to every detail. When they were finished there was not a speck of dust or dirt to clean. They even had their own floor covers to prevent any dirt coming into the house. I can’t say enough about the level of service and professionalism we received from start to finish. I would highly recommend this company.

Read all reviews on Google

Before you hire a window and door installer in Ontario

No provincial licence is required. Installation quality is governed by manufacturer specification and the Ontario Building Code rather than by a trade certificate.

General liability insurance and WSIB clearance

Standard checks. Window installation involves ladder work and heavy glass.

Manufacturer-trained installer status

Matters more than usual here, because most window warranties are voided by installation that departs from the manufacturer specification.

Building permit for new or enlarged openings

Replacing a window in an existing opening generally does not need one. Cutting a new opening, or enlarging one for a basement egress window, generally does.

Verify with: Your municipal building department confirms what your specific job requires.

ENERGY STAR certification for the product

Relevant if you intend to claim any efficiency rebate, which typically requires certified products and documentation.

Questions worth asking

Is this a retrofit or a full-frame installation? What would the other one cost?
How is the gap between the window and the rough opening insulated and air-sealed?
Is exterior capping included, and in what colour and material?
Is the warranty on the glass seal, the frame, and the labour - and are they different lengths?
Is the warranty transferable if I sell the house?

Read the full window & door installers hiring guide