Home | Frequently Asked Questions

Have a question about our vinyl replacement windows? Here are some questions we most often get at Great Lakes® Window. We want you to select your energy efficient windows with confidence, and we’re here to help you get answers to your questions. If you can’t find what you’re looking for, please contact us and we’ll quickly get back to you.


Q. What are double hung windows?
A. double hung windows come with two vertically-sliding sashes in a single frame.


Q. On Great Lakes Window double hung units, do both sash tilt for easy cleaning?
A. Yes, Great Lakes Window double hung units are designed for both top and bottom sash to tilt in for easy cleaning.


Q. What is a sliding window?
A. Sliding windows offer horizontally sliding sashes that slide in either direction in a single frame and lift out for easy cleaning.


Q. What are casement and awning windows?
A. Casement and awning hinged windows come standard with a sash that cranks outward and pivots 90° for easy and safe cleaning.


Q. What are architectural shaped windows?
A. Shapes and configurations such as half-round, quarter-round, full-round (circle), pentagons, trapezoids, left and right triangles, eyebrows, arch, elliptical as well as many other shapes are available as design elements to fit your home’s unique style.


Q. What are bay windows?
A. Bay windows are comprised of three windows, typically featuring a large center unit and two flanking units at 35° or 45° angles to the wall. They usually have two double hung or casements as the flanking units with a picture window in the center.


Q. What are bow windows?
A. Bow windows feature four or more window units in a radial or bow formation.


Q. What is a garden window?
A. Garden windows are three-dimensional windows project from the exterior wall of the home can be configured with glazing on all sides except the bottom, which serves as a shelf for plants or other keepsakes.


Q. What is a sliding patio door?
A. Sliding patio doors offer space-saving sliding doors, either right or left or center operating (Center operating only available in 4-panel configuration) in 2, 3 or 4 panel configurations with full-perimeter weatherstripping and adjustable rollers for smooth operation.


Q. Does Great Lakes Window make custom sizes?
A. Yes, replacement windows and patio doors are custom built for each home’s specifications and can be ordered in 1/8″ increments to accommodate any replacement application. This ensures a perfect fit and minimizes installation time and special trimming requirements.


Q. Why is vinyl a better material for windows?
A. Our vinyl windows start with a proprietary vinyl formulation manufactured in our lineal technology plant. They are designed to withstand harsh weather and resist conducting heat and cold. Vinyl windows are long-lasting, weather-tight and never need to be painted or stained, adding curb appeal that lasts a lifetime.


Q. Are windows from Great Lakes Window available in colors?
A. Yes, Great Lakes Window products are available in a variety of colors. On the exterior, White and Beige complement neutral palettes, while earthy colors such as Earthtone, Sandstone and Royal Brown are perfect for crafty, rustic styles. Evergreen, Dark Bronze and Black are a good choice for a bold look, or choose Shark Skin, an elegant gray that’s designer friendly on almost any home. Several of our products are also available with a woodgrain finish on the interior. View our colors page to learn more, or contact your local Great Lakes dealer to see the options available in your market.


Q. What is fusion welding?
A. Great Lakes Window manufactures vinyl windows that are entirely fusion welded – sashes and mainframes – to create a solid, one-piece unit that maintains its strength over the years. Our state-of-the-art fusion process ensures frame and sash corners are tight and square for a lifetime of smooth operation.


Q. What is SmartCore insulation?
A. SmartCore insulation is pre-expanded high-density solid-polyurethane which is the same material type used in many refrigerator/freezer doors. Available with ecoSmart and ComfortSmart windows, it prevents voids and settling and results in even distribution of the maximum insulating barrier.


Q. What is a SureLok sill?
A. HarborLight windows are manufactured with our SureLok sill, incorporating a sloped sill and vinyl sash lock that fits tightly to the sash, forcing water to drain to the exterior of the window, keeping your windows dry and tight.


Q. What is a Spacer system?
A. A spacer system reduces thermal transfer around the glass perimeter by utilizing a unique U-shaped channel to separate glass panes and interrupts the natural flow of heat to cold. It is one continuous piece creating a stronger, more energy-efficient insulated glass unit. EnergyEdge and EnergyEdge+ spacer systems are available with all of our product lines, and our maximum performing EnergyTek is available as an option with ecoSmart and ComfortSmart windows.


Q. What is Low-E (low emissivity) glass?
A. Low-E has a secondary, very thin metallic dual or triple layer coating. It reflects radiant heat waves, so it helps keep your home warmer in the winter and cooler in the summer. Low-E can reduce heating and cooling bills plus dramatically improve overall comfort.


Q. What is Argon gas?
A. Argon is a safe, odorless, colorless gas, which is heavier or denser than air. When paired with Low-E, it can provide better insulation.


Q. What is Krypton gas?
A. Krypton is a safe, odorless gas that improves thermal performance of a window. Denser than Argon, Krypton gas does an excellent job of preventing heat loss and provides excellent insulation.


Q. What is an STC (sound transmission glass) rated window?
A. STC ratings are the most widely recognized system for how much noise is blocked. Sounds are measured in decibels (dBs) and a STC rating is assigned to a window or patio door that indicates the amount of sound it will stop. The higher a STC rating, the better the window and door will block noise.


Q. How Does Easy-Clean® glass work?
A. Optional advanced Easy-Clean glass is an ultra-thin and transparent coating that completely adheres to the glass protecting it from water and oil-based stains, resulting in clearer views and less frequent exterior window cleaning compared with ordinary glass.


Q. What is U-factor?
A. U-factor is a measure of the rate of heat flow through a window. The greater a window’s resistance to heat flow the better its insulating properties. A lower U-factor indicates a higher performing window that can help reduce heating and cooling costs.


Q. What is Solar Heat Gain Coefficient (SHGC)?
A. SHGC is the fraction of incident solar radiation transmitted through a window and absorbed inward. SHGC is expressed as a number between 0 and 1. The lower the number, the less solar heat gain the window permits.


Q. What is visible light transmittance (VT)?
A. VT is the fraction of visible light transmitted through the window. A high VT is desirable to maximize daylight.


Q. What does DP CERTIFIED mean?
A. Great Lakes windows are tested to meet the air, water and structure requirements of AAMA/WDMA 101/I.S.2.


What is Great Lakes Window warranty?
Great Lakes offers a Limited Lifetime Warranty. For more information about our competitive warranty, visit our Warranty page.


How do I find the closest dealer to me?
Our dealers are located in the United States. To find your local Great Lakes Window dealer, simply visit our Find a Dealer page.


How do I register my warranty?

To register your warranty, fill out the form on our Warranty Registration page.