FAQ

Keller Window & Door installs replacement windows and doors in O Fallon, MO. They are a local window supplier and installer serving the O Fallon area and the broader St. Louis metro region.

Keller Window & Door carries and installs name-brand replacement windows — contact the team directly to confirm current product lines available for your project. Choosing a dealer tied to recognized manufacturers gives you access to manufacturer-backed warranties and consistent product quality.

An Elite Certified Contractor designation means the installer has met a window manufacturer's highest standards for product knowledge, installation technique, and customer service. It matters because certified installations typically qualify for enhanced manufacturer warranties that non-certified installs do not, giving you stronger long-term protection on your investment.

Most single-window replacements are completed in about one to two hours per window once the crew is on site. A full whole-home window project commonly takes one to two days depending on the number of units, window style, and site conditions.

A standard entry door replacement is typically completed in a single day. More complex installations — such as doors with sidelights or custom frames — may require additional time, but a professional crew can usually have your home secure and weather-tight before they leave.

Yes, Keller Window & Door offers financing options for window and door replacement projects. Financing allows homeowners to move forward with energy-efficient upgrades without paying the full project cost upfront.

Keller Window & Door serves O Fallon and the surrounding St. Louis metro area. If you are unsure whether your address falls within their service area, reaching out to the team directly is the fastest way to confirm.

A certified local contractor brings hands-on knowledge of regional building codes, weather conditions, and permit requirements that national chains may not prioritize. Local installers also tend to be more accountable for their work because their reputation depends on the communities they serve every day.

A window repair addresses a specific component — such as a broken seal, failed hardware, or damaged sash — while a full replacement removes the entire existing window unit and installs a new one. Replacement is typically recommended when frames are rotting, windows are no longer energy-efficient, or the existing unit cannot be repaired cost-effectively.

Common signs that windows need replacing include drafts around the frame, condensation forming between panes, difficulty opening or closing the sash, and noticeably higher heating or cooling bills. If multiple windows in your home show these signs, a full replacement assessment is usually the right next step.

Yes, Keller Window & Door handles both window and door replacements, so homeowners can coordinate both scopes of work with one contractor. Bundling window and door work with a single installer simplifies scheduling, ensures consistent installation quality, and can reduce overall project disruption.