WINDOW STYLES
Double-Hung Windows, and When a Single-Hung Is Enough
Two sashes that slide vertically and tilt into the room. It is the default US replacement window, which is exactly why it is worth checking whether every opening in your house needs one.
Two vertically sliding sashes · balances concealed in the jambs · both sashes tilt inward
Who it's for
Openings taller than they are wide, upper floors where the outer glass is awkward to reach, and any elevation where nothing may swing out over a path, a deck or a driveway.
How it opens
Each sash travels in its own track and parks in front of the other, so about half the opening is ever uncovered. Both sashes pivot into the room for cleaning on nearly every replacement unit.
Cost drivers
Opening size first, then the frame material, then the glass package, then access — the same unit costs more above a ground floor. The published national figures sit on the cost guide.
Where a hung window belongs, and where it does not
One mechanical arrangement, two lists. The right-hand column is where a different style is usually the better answer.
Where it is the right answer
- Tall openings, where splitting the height gives two sashes of sensible proportion
- Upper floors, because both sashes tilt in and the outer glass is washed indoors
- Rooms that want to vent high and low at once, with a movable upper sash
- Walls with a path, a deck rail or a storm door inside the swing of any hinge
- Houses where a traditional sightline is part of the point
Where something else fits better
- Wide, short openings, which give two broad sashes awkward to lift and to seal
- Rooms that need every square inch of air the hole can deliver
- Openings whose job is to hold a view, where frame members eat the glass area
- Ground-floor windows opening onto a lawn, where tilt-in is rarely used
- Anywhere the upper sash will never be opened and is only parts to fail
What the tilt-in feature is worth
- Second story over a flowerbed. The difference between a window that gets cleaned and one that does not.
- Ground floor onto a lawn. A convenience you are paying for and will probably use twice.
- A movable upper sash. Lets warm air leave at the ceiling while cooler air enters low.
- Small children or a cat. Venting from the top means no gap at floor level.
Walk the house and mark which openings are genuinely hard to reach and which want to vent high. Those are the ones where the premium is doing work.
The other four styles
A wide, short hole usually wants a horizontal arrangement; an opening that has to move as much air as possible usually wants a sash that swings clear.
How the two sashes work
One frame, two tracks, and a counterweight system hidden in the jambs.
A hung window puts its sashes one above the other in the same frame and lets them travel vertically past one another. The outer track carries the upper sash, the inner track carries the lower, and the two overlap in the middle at what the trade calls the meeting rail. Because the sashes move in their own plane, nothing swings into a room or out over a path, which is why this style survives in places where a hinged window simply could not be used.
What holds a sash at whatever height you leave it is a balance concealed in the jamb — a spring or a coil mechanism replacing the sash weights and cords that did the same job in a nineteenth-century window. Modern replacement units add a pivot at the base of each sash so the whole sash can be tipped into the room. That pivot, and the small latches that release it, are the mechanical difference between a window you can clean from inside and one you cannot.
The seal follows from the same arrangement. It is made by contact along sliding surfaces rather than by pulling a sash tight against a gasket, which is a real difference in how the window behaves in wind and is reported on the performance label of every certified unit.
Double-hung against single-hung, line by line
The same window with one fewer moving sash. What that removes, and what it saves.
| What changes | Double-hung | Single-hung |
|---|---|---|
| Which sash moves | Both, independently | The bottom sash only |
| Cleaning the outer glass | Both sashes tilt into the room | Lower sash tilts; upper glass is reached from outside |
| Venting pattern | Top and bottom at the same time | Bottom of the opening only |
| Moving hardware | Balances, pivots and latches on two sashes | One set of balances, one pivot |
| Parts that can fail | Roughly double the mechanism | Fewer components in the jamb |
| Relative price per unit | The higher of the pair | The lower of the pair |
A structural comparison, not a price quote. The published national cost figures this site can cite are not broken down by style, so no dollar difference is stated here.
The practical use of that table is mixing the two in one order. A quote that specifies double-hung units upstairs and single-hung units at ground level is not a cheaper quote for the same thing — it is a quote that matched the hardware to the opening. Ask for it priced both ways.
What actually fails on a hung window
Six components, none of which is the glass. Worth knowing before a company tells you the window is beyond repair.
The balances
Each moving sash is held at any height by a balance inside the jamb. A sash that will not stay up, or that slams, is usually a balance rather than the window.
The jamb liner
The channel the sashes run in is also part of the seal. A liner that has been distorted by a forced sash leaks air long before the glass shows anything.
The tilt latches
Small plastic catches at the top of each sash. They are the part most often broken by a cleaning routine that is slightly too enthusiastic.
The meeting rail
Where the two sashes overlap in the middle. The weatherstripping along that line does a lot of work and is the first place to check for a draft.
The sash lock
On a hung window the lock is not only security: it pulls the two sashes together and holds the meeting rail closed. A loose one is an air-leakage problem.
The sill and its weep holes
Water that gets past the outer sash is supposed to leave through small drainage openings at the sill. Painted over or blocked, it stays inside the frame.
Frame material is the other large lever on the price, and it is a separate decision from the hardware: the same double-hung window in a vinyl frame and in a clad-wood frame are separated by more money than most style decisions.
Double-hung questions
Decide the hardware, then collect quotes
Mark which openings need two moving sashes, and ask for the rest priced separately.