One operable sash — lower cost, fewer failure points, tighter seal
A single-hung window looks identical to a double-hung from the street. The difference is entirely functional: the top sash is fixed in the frame and only the bottom sash slides.
Double-hung has taken most of the residential market over the last thirty years, and for good reasons covered below. But the single-hung has not gone away, and on certain projects it is the better specification rather than the cheaper compromise.
This page covers what you give up, what you gain, and the specific situations where we would recommend it.
| Single-Hung | Double-Hung | |
|---|---|---|
| Operable sashes | Bottom only | Both |
| Tilt-in cleaning | Bottom sash only | Both sashes |
| Convective ventilation | No | Yes |
| Moving parts | Roughly half | Two balance sets, two locks, more weatherstrip |
| Frame rigidity | Fixed top sash braces the frame | Less inherently stiff |
| Typical cost | Roughly 10–25% less | Baseline |
| Exterior clearance | None needed | None needed |
The comparison is not close on convenience. It is much closer on engineering, and closer still on cost.
Two reasons, and both are real rather than marketing.
Cleaning. On a double-hung both sashes tilt inward, so the exterior glass is washed from inside the room. A single-hung's top sash is fixed — it can only be cleaned from outside. On a ground floor that is a minor errand with a hose. On a third-floor apartment it means a ladder, specialist equipment, or paying someone. That single difference is what shifted the market.
Convective ventilation. A double-hung opened top and bottom sets up a circulation loop — warm air out the top, cool air in the bottom — and ventilates a room without a fan. A single-hung opens at the bottom only, so there is no return path and no loop.
If either of those matters for the opening in question, specify double-hung and stop reading. The rest of this page is about the situations where they do not.
Cost, at volume. The saving is 10–25% per unit depending on material and manufacturer. On a twenty-window replacement that is thousands of dollars, and the honest question is whether it is better spent on the operation you will rarely use or on a better glass package across every opening. Our view is usually the glass. See Low-E glass for why.
Fewer things to fail. One operable sash means one set of balances, one lock, and half the operable weatherstrip. Balance failure is the most common fault on hung windows, and a single-hung has half the exposure to it. On a rental portfolio, where maintenance calls are the running cost, that matters more than the purchase price.
A stiffer frame. The fixed top sash acts as a cross-brace, so the frame is inherently more rigid than one with two moving sashes in it. On large units, where sash weight puts real stress on the frame, that is a structural advantage rather than a technicality.
Potentially tighter sealing. The weak point on any hung window is the meeting rail. On a double-hung that junction is a friction seal between two moving parts. On a single-hung the bottom sash locks against a permanently fixed member, which can be engineered as a firmer, more consistent seal — and there is less operable interface overall for air to pass. Well-made single-hungs frequently post better air infiltration figures than their double-hung equivalents. Compare the actual ratings rather than assuming, since it varies by line.
Accessible openings. Ground floor, over a porch, anywhere the exterior can be reached easily. The cleaning objection disappears and the cost saving remains.
The Andersen 100 Series is the most commonly specified single-hung in this market. It is made entirely from Fibrex, Andersen's composite of reclaimed wood fibre and thermoplastic polymer, which is around twice as strong as vinyl and holds up in temperature extremes better. Standard sizes run to about 4 feet wide by 7 feet 6 inches high, with custom sizing available.
One point worth correcting, because it was true until recently and is repeated widely: the 100 Series used to be single-hung only in its vertically operating window. That has changed. Andersen now offers a 100 Series double-hung, and it is available in the Northeast — which includes us.
That matters for your decision. The choice between single and double-hung in this line is now a genuine choice rather than a consequence of what was available, and the double-hung version brings tilt-in cleaning on both sashes at the same Fibrex value proposition.
The 100 Series also covers awning, casement, gliding, picture and specialty shapes. See our Andersen page for how the series compare.
At the other end of the range, the A-Series offers single-hung as a custom-ordered option — specified for historic work where a fixed top sash is required for accuracy, or where an architect wants the cleaner sightline it allows.
Pella offers single-hung primarily in its vinyl lines — the 250 Series and Encompass — and as a custom option elsewhere.
Marvin concentrates on double-hung in the premium wood lines, with single-hung appearing in the fiberglass composite ranges where it helps keep pricing competitive.
Vinyl manufacturers including Alside and Crystal support single-hung across their ranges, and this is where the cost advantage is largest in absolute terms.
Vinyl is the standard for budget residential work — good thermal performance, no maintenance, lowest cost. The limitation is stiffness: vinyl frames must be relatively thick to carry the glass, which caps how large a unit can go before it sags, and means less glass in the same opening.
Fiberglass and composite is the performance choice. Fibrex and pultruded fiberglass are considerably stronger than vinyl, so profiles can be narrower and units larger. They also expand and contract far less with temperature, which is what protects the seal over decades — the frame is not working against the glass through every hot and cold cycle.
Clad wood is for historic and high-end work, with a wood interior and a low-maintenance exterior. This is where a single-hung is chosen for fidelity rather than budget.
On many Victorian and early twentieth-century buildings the original windows were single-hung, or fixed. Where a preservation commission is judging the replacement, the fixed top sash is sometimes what the approval requires.
There is also a sightline argument. A fixed top sash allows a cleaner, sometimes thinner meeting rail than a fully operable double-hung, and on a building where the original profile was slender, that difference is visible.
This is a case where the single-hung is the premium specification rather than the economy one. See permits and approvals for how landmark requirements constrain a window choice, and Optimum Window where the original was steel.
For most New York replacement work we would specify double-hung, because most of the housing stock is walk-ups and apartment buildings where cleaning the outside of an upper-floor window is a genuine problem.
We would specify single-hung where the openings are accessible from outside, where the budget is better spent on glass than on operation, on rental and investment property where fewer moving parts reduces maintenance calls, and on historic work where the fixed top sash is required or preferred.
Tell us the building, the floor, and what the budget has to cover. If a single-hung would free up enough to put better glass in every opening, we will say so — and if it would leave you with windows you cannot clean, we will say that instead.
Double-Hung Windows Casement Windows Andersen Windows Alside Sash Balances Low-E Glass
In a single-hung only the bottom sash opens; the top sash is fixed. In a double-hung both sashes slide and both tilt in for cleaning. From outside they look the same.
Yes, typically 10 to 25 percent less than an equivalent double-hung, because there are fewer moving parts, simpler balances and no tilt mechanism on the upper sash.
Only the bottom sash. The fixed top sash must be cleaned from outside, which is why single-hung suits ground-floor and accessible openings better than upper floors.
They can be. The bottom sash locks against a fixed member rather than another moving sash, and there is less operable interface overall, so well-made single-hungs often post better air infiltration figures. Compare the actual ratings, as it varies by line.
Yes — the 100 Series single-hung in Fibrex composite, and single-hung as a custom option in the A-Series. Note that Andersen now also offers a 100 Series double-hung, available in the Northeast, so both configurations are available in that line.
Tell us about the opening and we will specify it for you.
