A double-hung window is a window with two sashes, an upper one and a lower one, that both slide up and down inside the same frame. You can open the top, the bottom, or both. Most modern ones tilt inwards so you can clean the glass from indoors.
Key Takeaways
- A double-hung window has two moving sashes, so you can open it from the top, the bottom, or both at once.
- Both sashes usually tilt inwards, which lets you wash the outside glass while standing safely inside.
- It looks classic and suits older GTA homes, yet a modern vinyl version seals tightly for Canadian winters.
- An ENERGY STAR™ certified window is about 20% more efficient than an average window.
- Windows, doors, and skylights can leak a big share of a home’s energy, so the seal matters as much as the style.
What Is a Double-Hung Window?
A double-hung window holds two sashes, an upper and a lower, stacked in one frame. Both slide vertically, so you can lower the top sash, raise the bottom sash, or move both. A sash is simply the moving part that holds the glass.
Think of it like a sash-and-frame sandwich. The frame is fixed to the wall. The two sashes sit inside it on tracks and counterbalances, so they glide and stay put wherever you leave them. Older versions used ropes and weights; today’s vinyl windows use hidden spring balances.
This is different from a single-hung window, where only the bottom sash moves and the top one is fixed. With a double-hung window, both panes work, which gives you more ways to let air in and an easier time cleaning.
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Why Does a Double-Hung Window Matter?
It matters because it shapes three things you feel every day: airflow, cleaning, and comfort. Opening the top and bottom together creates a gentle loop of air, warm air leaves up high while cool air comes in low. A tight, well-sealed unit also keeps heat in and draughts out through a GTA winter.
Comfort and bills are linked here. NRCan reports that windows, doors, and skylights can be a significant source of energy loss, up to 25% of a home’s total. So the quality of the seal and glass really changes how warm your rooms feel and what you pay to heat them.
There’s a money angle too. NRCan notes that windows, doors, and skylights can account for up to 35% of a home’s heat loss in the “Keeping the Heat In” guide. A draughty old double-hung window is often part of that, which is why a sealed, ENERGY STAR™ certified replacement pays you back in comfort.
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How Does a Double-Hung Window Work?
Two sashes ride in vertical tracks built into the frame. Each sash connects to a balance system, usually a hidden spring, that carries its weight so it glides smoothly and holds its position. Tilt latches let you pivot each sash inwards for cleaning.
The balance is the clever bit. Without it, a heavy sash would drop the moment you let go. The spring takes the weight, so a light push is enough to raise or lower the pane. When the balance wears out, the sash starts to slip, which is a common repair on old units.
Locks pull the two sashes tight against the frame and against each other. On a quality build, that locking action also squeezes the weatherstripping flat, which is what makes the window airtight when shut. Our Total Seal Lock System uses multi-point locking with two to three adjustable lock points to hold that seal.
What Are the Parts of a Double-Hung Window?
The main parts are the frame, two sashes, the glass (often a sealed insulated unit), the balances that carry the sash weight, the weatherstripping that blocks draughts, and the locks. Tilt latches and a sill complete the set on most modern units.
Here’s how the key parts do their jobs in plain terms. Each one is small on its own, but together they decide how the window seals, slides, and lasts.
- Frame: the fixed outer box, screwed to your wall, that everything else sits in.
- Sashes: the two moving panels that hold the glass and slide up and down.
- Balances: hidden springs that carry sash weight so the panes glide and stay put.
- Weatherstripping: soft seals that close the gaps and stop draughts and water.
- Glass unit: two or three panes sealed with a gas fill and a low-E coating for warmth.
Double-Hung vs Single-Hung Windows: What’s the Difference?
The difference is which sashes move. A double-hung window has two moving sashes, top and bottom. A single-hung window moves only the bottom sash; the top is fixed. Double-hung units give you more airflow and easier cleaning, but they usually cost a little more.
Both look almost identical from the street, so the choice comes down to how you use the window. If you want top-down airflow or you want to tilt both panes in to clean an upstairs window, the double-hung wins. If budget is tight and the window is easy to reach, a single-hung does the job.
| Feature | Double-hung window | Single-hung window |
| Moving sashes | Top and bottom | Bottom only |
| Top-down airflow | Yes | No |
| Tilt-in cleaning | Both sashes | Lower sash only |
| Typical price | Higher | Lower |
| Classic look | Yes | Yes |
If you’d like to compare them on your own home, our single-hung windows page sits next to the double-hung range so you can weigh both side by side.
Pros of a Double-Hung Window
- Open the top, the bottom, or both for flexible airflow.
- Both sashes tilt in, so you clean outside glass from indoors.
- Classic look suits older GTA homes and heritage streets.
- Easy to fit with a screen and to add child-safety limits.
Cons of a Double-Hung Window
- Usually costs more than a single-hung window.
- Two moving sashes mean a touch more upkeep over time.
What Glass and Coatings Go in a Double-Hung Window?
Most quality double-hung windows use a sealed double or triple glazing unit with a gas fill and a low-E coating. Double glazing has two panes; triple glazing adds a third for more warmth. A low-E coating is a thin, clear layer that reflects heat back into the room.
The gas between the panes does quiet, important work. We fill ours with argon, an inert gas that slows heat from passing through. Argon fills improve glazing efficiency by roughly 25 to 30% over plain air, in our own testing, which you feel as fewer cold spots by the glass.
Triple glazing reaches U-factors of about 1.0 to 1.3 W/m²K, while typical double glazing sits near 1.6 to 1.9 W/m²K. A lower U-factor means less heat escapes. Triple glazing costs roughly 20 to 30% more, so it’s worth it on cold, north-facing rooms but optional elsewhere.
How Does a Double-Hung Window Work in a Real Home?
Picture a bedroom over a GTA driveway in January. The old double-hung window rattles, the lower sash leaks a thin draught, and the glass feels icy by your hand. Swap in a sealed, ENERGY STAR™ certified vinyl unit and that wall corner stops feeling cold, because the seal and the warm glass do their jobs.
The summer side is just as real. On a warm evening you drop the top sash a hand’s width and raise the bottom a little. Warm air drifts out the top, cooler air slides in the bottom, and the room flushes itself without a fan.
“In a Toronto winter, the seal does most of the work, not just the glass,” says a senior product engineer at TotalSeal. “A double-hung window can perform beautifully if the weatherstripping and the multi-point lock pull the sashes tight every time you close them.”
How Do You Get Started With a Double-Hung Window?
Start by checking your current windows for three signs: draughts you can feel, fog or moisture between the panes, and sashes that stick or slip. Then measure the rough opening and note whether you want a retrofit (frame stays) or a full-frame replacement (everything comes out).
A foggy pane between the glass is a clear tell. It means the seal on the glass unit has failed, and no amount of cleaning will fix it. That window has stopped insulating properly and is a strong candidate for replacement.
“Measure twice and look at the existing frame before you order anything,” says a lead installation manager at TotalSeal. “Nine times out of ten a clean retrofit works, but if the old frame is rotten or out of square, a full-frame replacement is the honest call, and it seals far better.”
When you talk to an installer, ask what U-factor the glass hits, whether the unit is ENERGY STAR™ certified for your zone, and how the sashes are balanced and locked. You can browse our double-hung windows range to see the builds and options first.
Common Mistakes to Avoid
The most common beginner mistakes are easy to dodge once you know them. Each one below comes with the simple fix, so you can avoid an expensive do-over.
- Buying on looks alone: also check the U-factor and the ENERGY STAR™ certification, not just the frame style.
- Ignoring the install: a great window fitted badly still leaks, so use certified installers.
- Skipping the seal check: feel for draughts and look for fog before you decide what to replace.
- Forcing a stuck sash: a sash that won’t glide usually needs a new balance, not muscle.
- Mismatching the style: a modern frame on a heritage brick home can look off, so match the street.
Bringing It All Together
A double-hung window is one of the most flexible, familiar styles you can fit, two sashes that slide, tilt in to clean, and seal tight when shut. The style is timeless; the performance comes down to the glass, the seal, and a careful install. Get those right and you gain comfort, lower draughts, and a window that suits your street.
When you’re ready to see what your project might cost, our cost estimator gives you a quick, no-pressure ballpark before you book a free in-home visit.
Frequently Asked Questions
Are double-hung windows good for Canadian winters?
Yes, when they’re well built. A vinyl double-hung window with tight weatherstripping, a multi-point lock, and ENERGY STAR™ certified glass seals firmly and holds heat well through a GTA winter.
Do double-hung windows tilt in for cleaning?
Most modern ones do. Both sashes pivot inwards on tilt latches, so you can wash the outside glass while standing safely inside. Older units may not tilt, so check before you buy.
Are double-hung windows more expensive than single-hung?
Usually yes. A double-hung window has two moving sashes and balances instead of one, so it costs a little more. In return you get top-down airflow and easier cleaning on both panes.
How long do double-hung windows last?
A quality vinyl double-hung window commonly lasts 20 years or more. Balances and weatherstripping may need attention sooner, but the frame and fusion-welded corners are built to last through decades of Ontario weather.
What is the difference between a sash and a frame?
The frame is the fixed outer box attached to your wall. The sash is the moving part that holds the glass and slides up and down inside that frame. A double-hung window has two sashes.
Can you open just the top of a double-hung window?
Yes. That’s a main reason to choose one. Lowering only the top sash lets warm air escape up high while keeping the lower opening closed, which is handy for safety with children or pets nearby.
Why does my double-hung window have fog between the panes?
The seal on the sealed glass unit has failed, letting moisture in. Cleaning won’t help, because the fog is inside. That window has lost much of its insulating value and is a good candidate for replacement.
