What is a Double-Hung Window?

Double-hung windowA double-hung window refers to a window with two vertical sashes, or frames, that can be moved. This charming design allows greater ventilation and emergency access in case of fire.

Design Features

Upper and lower panes on a double-hung window can be lowered and raised, unlike single-hung windows with fixed top sashes. Shutters traditionally supported the sashes. Simplex hinges allow it to be locked into position on either side. Wood, fiberglass, and vinyl are materials of choice, according to Simonton.

How Double-hung Windows Work

Counterweights traditionally support the sashes as they move along pulleys made of either braided cord or specialty chain. Spring balances used in modern construction come in either a clock spring balance, a tube balance or block-and-tackle balance.


Safer for kids’ bedrooms, the bottom half can remain closed while the top is open. The space-saving feature of sliding up and down instead of tilting out is well suited to high traffic areas and window-treatment friendly.


Air leaks more from double-hung windows than others. Slightly restricted air flow. If the counterweights fail or window is not hinged, the top half can crash and seriously injure little fingers or pets perched on its sill. Aluminum is the least energy-efficient material for double-hung windows.

Related Resource: Install Double-Hung Windows

Precise measurements are a must to stop moisture and air leaks. Sashes come in many colors and have energy ratings for colder climates.