In a double-hung window both sashes slide up and down, while in a single-hung window only the bottom one moves.
Double hung
- Both sashes move up and down.
- Easy to clean from inside.
- Better ventilation.
- Costs more.
Single hung
- Only the bottom sash moves.
- Cheaper, with fewer parts.
- Less ventilation.
Choosing
Double hung for upper floors and cleaning ease. Single hung for budget.
Cost
Single hung $200 to $600. Double hung $300 to $800 per window.
Window operation
A double hung window has two movable sashes that slide up and down. A single hung window has a movable bottom sash and a fixed top sash.
Ventilation
Double hung windows allow air flow from the top and bottom at once, which promotes natural convection: hot air exits the top and cool air enters the bottom. Single hung windows can only open from the bottom.
Cleaning
Many double hung windows tilt inward for easy cleaning from inside. Single hung windows are generally cleaned from outside, which is harder on upper floors.
Cost
Single hung windows usually cost less, about 100 to 300 dollars less per window than double hung. Typical window costs including installation range from 300 to 1,200 dollars per window, depending on material and size.
Energy efficiency
A fixed top sash on single hung windows has fewer seals and so leaks less air. The difference is small. Look for ENERGY STAR labels and low U-factor and solar heat gain ratings from the National Fenestration Rating Council.
Durability
Fewer moving parts in single hung windows means fewer failure points. Double hung windows have more hardware, such as balances, which may need repair.
Safety for children
With double hung windows, you can open only the top sash to keep children away from open window space.
Historic homes
Many older homes have double hung windows, and replacements often match this style.
Egress
For bedrooms, building codes require an escape-capable opening of at least 5.7 square feet (5.0 for ground floor) in most US codes. Check your local code.
Materials
Vinyl, wood, fiberglass or aluminum. Vinyl is the most common due to low cost and low maintenance.
How the sashes work
A double hung window has two sashes that both slide up and down, so you can open the top, the bottom or both for ventilation. A single hung window has a fixed top sash and only the bottom moves. Many double hung windows tilt inward for cleaning from inside. Single hung windows are usually less expensive and have fewer moving parts and air leakage points, and they work well in standard rooms. Double hung windows offer better airflow control, since warm air can escape from the top while cool air comes in at the bottom.
Cost, safety and materials
Prices vary by size and material, and double hung windows cost more, often by around 10 to 25 percent. Frames come in vinyl, wood, fiberglass and aluminum. Look for the ENERGY STAR label and U-factor and solar heat gain ratings. Both types can meet egress requirements for bedrooms if the opening is large enough, usually at least 5.7 square feet of clear opening on upper floors. Window stops and guards help protect small children from falls. Historic homes often use double hung windows to preserve character.
Based on data from ENERGY STAR and the International Residential Code
