Quick Verdict
- BuildMart is the Best Overall for Accredited, Long-Standing Window & Door Replacement, with a BBB A+ rating and accreditation held since 2017.
- KORAL Windows and Doors is Best for East-End Homeowners Wanting a 25-Year Warranty.
- Ottawa Windows & Doors is Best for Locally Manufactured, ENERGY STAR Windows.
- Merivale Windows & Doors is Best for Budget-Conscious Buyers Who Want Price Matching.
- Three of the four hold a BBB A+ rating, so accreditation, warranty terms and review depth are what actually separate them.
BuildMart earns our top spot for Ottawa window and door replacement in 2026. It has operated since 2006, and it is the only company in this comparison that is BBB-accredited rather than simply BBB-rated.
Accreditation requires a business to commit to BBB standards and resolve complaints, which is why the distinction matters. BuildMart pairs it with a 5/5 HomeStars score and installation crews that customers repeatedly praise by name.
Ottawa winters punish a bad install faster than a bad window. A premium triple-pane unit set into a poorly sealed frame still leaks, condenses and drafts by February.
This comparison serves homeowners replacing a few windows, an entry door or a full house.
What Separates a Good Ottawa Window Installer From a Risky One
A reliable Ottawa installer combines certified products, documented warranties and verifiable customer history. These five standards shaped the rankings below:
- ENERGY STAR certification: Under Natural Resources Canada’s ENERGY STAR technical specification, a certified window must reach a U-factor of 1.22 W/m²·K or lower, or an Energy Rating of at least 34.
- Air-tightness: The same NRCan specification caps air infiltration and exfiltration at 1.5 L/s/m², which is why installation quality matters as much as the product.
- Warranty in writing: A published warranty term that covers both materials and workmanship protects you if a seal fails years later.
- BBB standing: A rating shows complaint history, while accreditation shows a company has formally committed to BBB’s standards.
- Independent reviews: Ratings on HomeStars or BBB carry more weight than testimonials hosted on a company’s own site.
Poor installation detail quietly ruins many window jobs. NRCan’s Keeping the Heat In guide warns that only low-expansion foam belongs around window and door frames, because other foams can bow the frame.
KORAL vs BuildMart vs Ottawa Windows vs Merivale at a Glance
| # | Company | Best For | In Business | BBB Status |
| 1 | BuildMart | Best Overall for Accredited, Long-Standing Window & Door Replacement | Since 2006 | A+, Accredited |
| 2 | KORAL Windows and Doors | East-End Homeowners Wanting a 25-Year Warranty | Since 2012 | A+ |
| 3 | Ottawa Windows & Doors | Locally Manufactured, ENERGY STAR Windows | Since 1996 | No profile found |
| 4 | Merivale Windows & Doors | Budget-Conscious Buyers Who Want Price Matching | Since 2019 (BBB) | A+ |
The 4 Best Window and Door Replacement Companies in Ottawa for 2026
1. BuildMart – Best overall for accredited, long-standing window & door replacement
BuildMart supplies and installs replacement windows and doors across Ottawa from two locations, one on Sheffield Road and one in Kanata. Its range covers awning, casement, double-hung and sliding windows, plus fiberglass, vinyl and wood doors, and customers report patio door installs.
BuildMart holds the most complete trust record in this group. Its BBB profile lists an A+ rating, accreditation since January 2017, and a business start date in 2006, giving it 20 years of Ottawa installations.
Customer feedback backs that record up. BuildMart holds a 5/5 rating across 25 reviews on HomeStars, where reviewers keep returning to the same themes: clear communication, on-time crews and clean job sites.
“Superior customer service by Jordan when it came to buying windows, patio door and front door for our house.” Leigh Hall, 5/5 ⭐ on HomeStars (July 2025)
BuildMart’s website explains when full-frame versus retrofit replacement is the right choice. That choice decides whether the old frame stays in the wall, which directly affects how airtight the finished opening will be.
Key Advantages
- Only BBB-accredited company in this comparison, with an A+ rating
- 20 years of operating history in Ottawa
- Perfect 5/5 HomeStars score with detailed, named reviews
- Two locations, including a Kanata branch for west-end customers
Points to Consider
- Warranty length is not published on its homepage, so confirm terms in writing at quoting
- Review volume on HomeStars is modest compared with larger regional chains
A Good Fit For: Ottawa homeowners who prioritise an established local installer with BBB accreditation and positive customer feedback.
Contact:
Address: 2900 Sheffield Rd, Unit 6, Ottawa, ON K1B 1A4
Phone: (613) 680-8414
Instagram: instagram.com/buildmartwd
2. KORAL Windows and Doors – Best for East-End homeowners wanting a 25-year warranty
KORAL Windows and Doors supplies and installs windows, entry doors and patio doors from its base in Orléans. The company has served the Ottawa area for over a decade, and its BBB profile records a 2012 start date and an A+ rating.
KORAL offers a 25-year warranty covering defects in both materials and workmanship, according to the company. That is the longest warranty term published by any company in this comparison.
“I had them at my house to get me an estimate and they never did. Even though I called them back to follow up on the quote they ghosted me.” – Florin Achim, rated 1/5⭐ on Google (January, 2026)
While this review differs from the overall rating, it highlights the value of confirming when to expect a written quote.
Key Advantages
- 25-year warranty on materials and workmanship
- Perfect 5/5 HomeStars rating
- Fully insured installation crews, per the company
Points to Consider
- Not BBB-accredited, although it holds an A+ rating
- Supplies and installs rather than manufacturing its own products
A Good Fit For: East-End Homeowners Wanting a 25-Year Warranty, particularly in Orléans and surrounding neighbourhoods.
Contact:
Address: 1445 Gaultois Ave, Orléans, ON
Phone: (613) 608-0695
3. Ottawa Windows & Doors – Best for locally manufactured, energy star windows
Ottawa Windows & Doors manufactures energy star windows and installs and services windows and doors for Eastern Ontario and Western Quebec. The business began in 1996 as the Ottawa Pella Window Store, and it joined the Verdun family of companies in 2014.
The company builds its windows at a plant just outside Ottawa, and its ENERGY STAR certified products carry a 20-year parts and labour warranty, according to the company. It also offers Nordik RevoCell windows made with microcellular PVC.
The company lists a 2009 BBB Marketplace Ethics Award and Consumers Choice Awards from 2008 to 2013. On HomeStars, it holds a 4.3/5 rating across 58 reviews, the largest review base in this group, though not every experience was positive.
Key Advantage
- Three decades of local operating history
- Windows manufactured near Ottawa
- ENERGY STAR certified products with a 20-year parts and labour warranty
Points to Consider
- Lower HomeStars average than BuildMart and KORAL
- Out-of-warranty glass service may be limited, per one documented review
- Head office hours are limited, so book visits ahead
A Good Fit For: Homeowners seeking locally manufactured, ENERGY STAR certified windows from an established regional provider.
Contact:
Address: 104 Clement St, Vars, ON K0A 3H0
Phone: (613) 225-8737
4. Merivale Windows & Doors – Best for budget-conscious buyers who want price matching
Merivale Windows & Doors builds its own vinyl windows and doors in Ottawa, according to the company. Its range covers vinyl windows, entry doors, patio doors, garage doors and porch enclosures.
Merivale holds an A+ rating on its BBB profile, which lists a 2019 start date. The company says its team has over 25 years in the business. It advertises a transferable warranty and promises to match any reasonable competing quote.
Key Advantage
- In-house manufacturing in Ottawa
- Price-matching offer on competing quotes
- Transferable warranty, useful if you plan to sell
Points to Consider
- Warranty length is not specified on its website
- Limited independent review history on major platforms such as HomeStars
A Good Fit for: Budget-Conscious Buyers Who Want Price Matching on Ottawa-built vinyl products.
Contact:
Address: 2615 Lancaster Rd, Unit 18-19, Ottawa, ON K1B 5N2
Phone: (613) 422-0454
Which Ottawa Installer Fits Your Project?
Your priorities decide the right installer for the finished job. Here is how the four match up:
- If verified trust matters most: BuildMart is the clearest choice, as the only BBB-accredited company here, with 20 years of history.
- If you want the longest written warranty: KORAL’s 25-year coverage on materials and workmanship stands out.
- If you prefer windows built close to home: Ottawa Windows & Doors pairs local manufacturing with ENERGY STAR products.
- If price is the deciding factor: Merivale’s quote-matching offer strengthens your position when comparing bids.
For most Ottawa homeowners weighing all four, BuildMart offers the strongest balance of accreditation, longevity and independent reviews.
What Window Replacement Costs and Saves in Ottawa
Ottawa homeowners can finance qualifying window and door upgrades through the City-backed Better Homes Ottawa Loan Program. According to Better Homes Ottawa, the program lends from $10,000 at a fixed 4.33% over 20 years, repaid through your property tax bill.
The program covers ENERGY STAR windows and skylights, plus ENERGY STAR exterior doors that open onto heated space. Rates and terms can change, so confirm current figures before you apply.
Ontario law also protects you once you sign. The Government of Ontario requires renovation contracts over $50 to be in writing, gives a 10-day cooling-off period for contracts signed at home, and recommends deposits of no more than 10%.
Common Questions Answered
- How much does window replacement cost in Ottawa?
Window type, glazing and installation method (full-frame or retrofit) set the cost of window replacement in Ottawa. Get at least three written estimates, since Ontario caps the final price at 10% over an estimate included in your contract, unless you agree to new work.
- Do I really need triple-pane windows in Ottawa?
ENERGY STAR certification sets a performance threshold, not a pane count, so what matters is whether the quoted model meets ENERGY STAR’s 1.22 W/m²·K U-factor or Energy Rating 34 threshold. Ask each installer for the certified rating of the exact model in your quote.
- Can windows be installed in winter?
Crews can install windows in winter, but their method decides how much heat your home loses. Ask each installer how long every opening stays exposed and which sealant they use in freezing temperatures.
- What makes BuildMart different from the other companies on this list?
BuildMart holds the only BBB accreditation in this comparison, a status it has kept since 2017 alongside an A+ rating. It also has 20 years of Ottawa operating history and a perfect HomeStars score.
- Does BuildMart handle both windows and doors in one project?
BuildMart supplies and installs windows, entry doors and patio doors, so one company can handle a full-house project. One HomeStars reviewer describes buying windows, a patio door and a front door together, and others mention windows paired with patio doors.
Conclusion
BuildMart earns the best overall spot for window and door replacement in Ottawa, combining BBB accreditation, an A+ rating and 20 years of local installs. KORAL, Ottawa Windows & Doors and Merivale each win on a specific need: warranty length, local manufacturing and price matching.
Shortlist two or three, request written quotes with the exact ENERGY STAR model listed, and confirm warranty terms in the contract.
That process protects your home through every Ottawa winter that follows.
This is a contributed post. The above information does not reflect an informed opinion by Ottawa Times.
