Series 3900 Windows

Double Hung, 2 and 3-Lite Sliders and Picture Windows

Our premier window, the 3900 features a number of deluxe enhancements made standard, a lifetime glass breakage warranty and our exclusive InsulKor™ sash technology for top-of-the-line energy efficiency and ultimate style.

Series 3900 double hung and sliding windows offer the option of the world’s first flexible window screen – FlexScreen! Learn more about RELIABILT Series 3900 windows on

Series 3900 Double Hung, Slider and Picture Windows Recognized as the Most Efficient of ENERGY STAR® in 2023.

Find A Lowe's Store

Instantly Book A Free In-Home Estimate

  • Series 3900 Double Hung Windows in White with Contoured Grid

Standard Features and Available Styles

  • Exclusive InsulKor™ polyurethane fiberglass enriched sash reinforcement, for superior thermal and structural performance
  • Sashes tilt in for easy cleaning from inside your home
  • Dual low profile locks increase security (2 locks standard at 27-1/4-in width or wider)
  • Dual push-button night latches position sashes for optimal ventilation and safety
  • Smooth sash operation with ¾-in constant force coil balances
  • Integrated slim line lift rail makes opening and closing the window easy
  • On sliding windows, tandem rollers ride easily along friction free glide channel
  • Standard with half screen on double hung and full screen on slider. Screens are removable from the inside*
  • Double Hung Design Pressure (DP) rating of 60 (window size tested 36-in x 74-in)
  • Slider Design Pressure (DP) rating of 50 (window size tested 72-in x 48-in)
  • 3-1/4-in jamb depth, ideal for most homes
  • 4-1/4-in frame thickness enhances appearance as well as provides structural integrity
Product Close-Up View
Series 3900 Double Hung Windows
Product Close-Up View
Series 3900 Slider Window

Vinyl Color Options



Painted Color Options


Brick Red



Dark Chocolate


Hunter Green



Note: Device/Monitor screen settings may affect color shown. Please refer to actual window sample when selecting colors. Laminates and exterior painted options available on select products, if they are not shown above they are not available on this product. Interior and exterior laminates available on white window only. Only use mild, water based household cleaner on painted product and rinse immediately with water. See full cleaning instructions for details. Grid offering limited to 5/8” contoured or SDL on exterior painted windows.

Grid Types

5/8-Inch Flat Grid

3/4-Inch Flat Grid

5/8-Inch Contoured Grid

1-Inch Contoured Grid

1-1/8-Inch Simulated Divided Lite (SDL) Grid

Grid Patterns




Perimeter Prairie


Glass Options

  • Low-E Glass
  • Ultra Low-E Glass with argon gas
  • Triple-pane, R-5 compliant glass with Low-E Glass with argon gas or Ultra Low-E Glass with argon gas
  • Super Spacer® sealant system (standard with triple-pane glass)
  • Obscure, tempered or double-strength glass

Additional Options

  • Window Opening Control Device (WOCD) to prevent falling from a window (factory applied)
  • InsulKor multi-cavity foam-filled frame
  • Nail fin accessory for use in remodeling or new construction applications
  • Factory mulling of twins and triples
  • Additional lock colors to complement any interior color
  • FlexScreen® – The World’s First and Only Flexible Window Screen
  • Clear View Screen Mesh
  • Heavy Duty Screen Mesh
  • Custom sizes available

World's First Flexible Window Screen

Like Superman – we found a way to bend steel. With some enhancements and engineering – FlexScreen was born.

RELIABILT Manufacturing Story

Our windows and sliding doors are recognized for their high-quality craftsmanship, innovative engineering and close attention to detail. Learn more about the process used to make them.


Looking for ENERGY STAR qualified products? Learn more about the climate zones and performance criteria used to identify ENERGY STAR compliant windows and doors.

Learn More

The RELIABILT Warranty

Every RELIABILT window and patio door is backed by a limited lifetime warranty on vinyl, glass and all working parts. Each product is individually registered with a product identification number, making ordering replacement parts throughout the warranty period easy and efficient.

Learn More

RELIABILT Product Care

RELIABILT windows and doors are designed for easy care and maintenance. Click the button below to download RELIABILT’s window and door care and maintenance guide.

Download Guide

Let's Get Started

Schedule a free, no-obligation in-home consultation with Lowe's to get RELIABILT windows and doors for your home today.