MI™ Replacement Windows

Superior Craftsmanship in a Vinyl Window

One of the nation’s largest suppliers of high-quality replacement windows, MI Windows and Doors has been manufacturing home-building products for more than 70 years. MI’s relentless focus on homeowner satisfaction and attention to detail comes through in their products, including some of the best vinyl replacement windows and new construction windows on the market.


MI windows are built with care and precision, down to the smallest detail—details such as:

  • Strong, energy-efficient vinyl construction
  • A welded, multi-chambered frame and sash
  • Stylish, beveled sashes for a high-end look
  • Innovative warm-edge spacer system that maximizes energy efficiency of insulated glass
  • Glass options that let you achieve better thermal performance
  • A range of exterior colors for great curb appeal

"*" indicates required fields




Your house isn’t just a house—it’s your home. And windows aren’t just windows—they are an integral factor in making your home feel good. If your current windows need replacing, you know firsthand the frustration of windows that stick, leak, look worn out, require constant maintenance, or make your favorite rooms uncomfortably drafty. But the prospect of replacing windows may also leave you feeling overwhelmed.

When you choose MI replacement windows from Big L Windows and Doors, these problems are solved. As a long-established with a great reputation for quality and service, MI windows offers a streamlined ordering process, unsurpassed customer service, and superior products. You’ll get windows that let abundant natural light into your home, function smoothly, are easy to maintain and energy efficient.

The same goes for MI new construction windows. You’ll enjoy handcrafted quality, durability and optimal energy efficiency—builder friendly, ENERGY STAR®-qualified windows with striking good looks. Welded-multi-chambered frames and sashes provide strength and thermal performance that will stand up to Buffalo’s extreme climate.


In the Buffalo area, it’s important to choose windows that will let in abundant natural light throughout the year, while keeping out the cold in the winter. MI continuously works to improve the energy efficiency of their windows and to meet the increasingly stringent requirements of ENERGY STAR® certification. By installing new MI windows, you will save money on heating and cooling bills and enjoy a more comfortable interior climate with fewer drafts and temperature swings.

Energy-efficient glass advances like argon gas fills boost thermal performance to keep your home warm and comfortable in cool weather, eliminating cold spots. Warm-edge spacer systems maximize the energy efficiency and improve the seal performance of insulated glass.

MI windows let you express your unique sense of style. Features like painted exteriors in a palette of classic colors—including on-trend bronze, black matte and clay—will upgrade the curb appeal of your home. Indoors, beveled sashes in your choice of white or almond color give you a clean, classic finish.

At Big L Windows and Doors, we’ll be happy to talk you through the myriad options MI Windows and Doors offers and help you decide what’s best for your home.