Hallmark Windows and Siding is a fan of the Sheffield window from Alside. Sheffield's Intercept Warm Edge Spacer System with high-efficiency insulated glass creates an effective barrier that helps to prevent heat loss during winter or heat gain during the hot summer months. The quality construction ensures that it won't rot, peel, split, corrode or pit. The premium virgin vinyl (PVC) forms the extra-thick walls of Sheffield's sturdy frames and sashes. It's tough, durable and other than an occasional washing, requires minimal maintenance.

To ensure easy opening and closing of the Sheffield Window, the Constant Force balance system and E-Gard operating hardware will continue to operate perfectly, even after decades of regular use. A sloped sill helps prevent water and air infiltration while maintaining the timeless detailed appearance characteristic of double-hung windows. Beveled mainframes on double-hung, sliding and casement windows provide a finished appearance complementing every home style.

Are Alside Sheffield Windows really that good? Independent tests give you an unbiased answer.

You expect us to say Sheffield Windows are technically superior. And we understand that you might want to verify our claim.

That's why we have independent testing and certification agencies test Sheffield Windows. Here's what their findings say:

- Sheffield Windows easily passed the rigorous air infiltration resistance testing procedure of the American Society for Testing and Materials (ASTM). ASTM E 283.

- Sheffield Windows resisted water infiltration during a test in which the equivalent of eight inches of rain an hour is blown onto the window at a simulated wind speed of approximately 60 mph. ASTM E 547.

- Sheffield Windows maintained their structural strength and integrity in tests simulating winds of over 155 mph. (This is the same wind speed reserved for Category 5 hurricanes by the National Hurricane Center). ASTM E 330. These tests were witnessed by independent testing laboratories utilizing the nationally recognized and accepted American Architectural Manufacturers Association (AAMA) test standards and criteria. Tough tests, tough judges, tough window. Sheffield Windows. The best way to look out on the world.

Your absolute guarantee of quality... the Alside Lifetime Limited Warranty.
Sheffield Windows are made by Alside, a recognized leader in product innovation, manufacturing excellence and uncompromising quality control. That's a reputation you can count on, from the day your windows are installed until the day you sell your home. And to make your buying decision easier, Alside backs all Sheffield Windows with its Lifetime Limited Warranty! Your assurance that we mean what we say.

Underwriters Laboratories approved.

The respected product safety organization, Underwriters Laboratories, has inspected and tested Sheffield Windows, certifying that they are UL Classified to ASTM E84