Casement windows seal tighter and usually perform better on paper. Double-hung windows are cheaper, simpler, and go places casements cannot. That is the honest summary, and the right answer changes room by room in the same house.
The physical difference is the whole explanation. A casement cranks shut and the sash compresses into the frame against a continuous seal. A double-hung slides past a weatherstrip. Compression beats sliding for airtightness, and it always will.
Head to head
| Double-hung | Casement | |
|---|---|---|
| Seal type | Sliding weatherstrip | Compression |
| Typical air leakage | Slightly higher | Lowest of common styles |
| Cost, comparable quality | Baseline | 10–25% more |
| Cleaning the exterior | Both sashes tilt in | Ladder, above ground floor |
| Screen location | Outside | Inside |
| Opens over a walkway | Fine | Problem |
| Ventilation control | Top and bottom, stack effect | Full opening, scoops side breezes |
| Hardware to fail | Balances | Crank operator, hinges |
| Egress compliance | Needs a bigger opening | Easier in a small opening |
Where casements genuinely win
Airtightness and performance numbers. If you compare NFRC labels between a casement and a double-hung from the same manufacturer's same product line, the casement will typically show a lower air leakage figure and often a better U-factor. That is a design advantage, not a marketing claim.
Small openings that need to meet egress. The residential code requires most emergency escape and rescue openings in bedrooms to provide a minimum net clear opening of 5.7 square feet, with minimum dimensions and a sill height limit. A casement opens almost its entire frame; a double-hung gives you only the bottom sash. In a tight opening, that difference decides whether the window is legal.
Catching a side breeze. An open casement is a scoop. It redirects air moving parallel to the wall into the room, which a double-hung cannot do. In a house that relies on cross ventilation, this is a real and underrated advantage.
Wide, uninterrupted glass. No meeting rail across the middle of your view.
Where double-hungs win
Cost. Meaningfully cheaper for the same size and quality, and there is no crank mechanism to eventually replace.
Cleaning. Both sashes tilt in. Second-story windows get washed from inside the bedroom in ten minutes rather than from a ladder in an hour.
Anywhere something is outside the window. Walkways, patios, decks, narrow side yards, driveways. An outward-swinging sash over a path is a hazard, and some jurisdictions restrict it. This single practical constraint rules out casements on a lot of elevations.
Air conditioners and fans. A window unit goes in a double-hung. It does not go in a casement without a specialized kit.
Stack ventilation. Open the top sash and the bottom sash and warm air leaves at the top while cool air enters at the bottom. It is a genuinely effective free cooling trick on a mild evening, and casements cannot do it.
Traditional appearance. On an older home, casements in every opening can look wrong in a way that is hard to unsee.
The hardware question nobody asks
Casement operators are mechanical assemblies. They work beautifully and then, somewhere around year ten to fifteen, one of them starts grinding, and you find out whether the manufacturer still stocks that operator. On an obscure or discontinued line, they often do not, and you are into universal replacements and a bit of improvisation.
Double-hung balances are simpler, more standardized, and cheaper to replace. Roughly $30 for a part and twenty minutes.
Neither is a reason to choose one over the other. It is a reason to buy from a manufacturer that will still exist in fifteen years, whichever style you pick.
Our actual recommendation, room by room
Bedrooms: casement, if the opening is small enough that egress compliance is tight. Otherwise either.
Anything over a walkway, patio, or driveway: double-hung, no discussion.
Kitchen over the sink: casement. The crank is reachable across a counter; a double-hung sash requires leaning over the sink and shoving.
Second floor, anywhere you will resent a ladder: double-hung, for cleaning alone.
Rooms that need cross ventilation: casement, angled to catch the prevailing breeze.
Bathrooms: either, but pick obscure glass and remember that casement screens live inside where they collect steam.
A whole traditional facade: double-hung, for appearance, and spend the money you save on better glass.
The opinion, since "both are good" helps nobody
If you are replacing windows in a mixed house and want one decision: buy quality double-hungs everywhere except the kitchen sink and any tight bedroom egress opening, and put the savings into a better low-E package.
The performance gap between a good double-hung and a good casement is smaller than the gap between a cheap window and a good one. Frame quality, glass coating, and installation matter more than the operating style. Choosing casements throughout and then economizing on the glass to afford them is backwards, and it is a trade people make constantly.
What actually matters more than either: the NFRC numbers on the label and whether the installer flashes the sill properly. Our energy-efficient windows guide covers reading those labels, and our repair versus replace guide covers whether you need new windows in the first place.
Decatur IL Windows installs double-hung windows, casements, and vinyl replacement units across Decatur and Macon County in central Illinois, and we will happily walk the house and tell you which openings genuinely want which style. Most homes end up with a mix, and that is the right answer.
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Decatur IL Windows money pages — go straight to the service you need.
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- Vinyl Windows →
Vinyl is the right material for most houses in this city, and the question that actually matters is not vinyl against something else. It is which vinyl, because in a staged job you have to be able to buy the same one again in four years.
- Double-Hung Windows →
The double-hung is what nearly every house here already has, and it is what will go back in. The decision that matters most is invisible from the street: which balance system holds the sash up, and whether the whole house ends up on one.
- Fiberglass Windows →
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- Wood and Clad Windows →
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Frequently asked questions
Which is better, double-hung or casement?
Casements seal tighter and usually post better air leakage and U-factor numbers, because the sash compresses against the frame when you crank it shut. Double-hungs slide past a weatherstrip instead. If airtightness is the priority, casement wins. If cost, simplicity, and screen placement matter more, double-hung wins.
Are casement windows more expensive?
Typically 10 to 25 percent more for a comparable size and quality, mostly because of the operating hardware. The crank mechanism and hinges are also the parts most likely to need service in year twelve, which is worth factoring into the comparison.
Can casement windows be used anywhere?
No, and this catches people out. A casement swings outward, so it should not open over a walkway, patio, deck path, or driveway where someone can walk into it. Some jurisdictions restrict it outright. Double-hungs and sliders have no such problem.
Which window style is better for egress?
Casement, usually. The residential code requires a minimum net clear opening of 5.7 square feet for most emergency escape windows, and a casement gives you nearly the whole opening when cranked fully open. A double-hung gives you only the bottom half, so it needs to be physically larger to comply.
Do double-hung windows leak more air?
As a category they test slightly higher on air leakage than casements, because a sliding seal cannot compress the way a crank-closed sash does. A well-made modern double-hung is still very tight — a cheap casement will lose to a good double-hung every time.
Which is easier to clean?
Double-hung, clearly. Both sashes tilt inward so you can wash the exterior glass from inside the room. Cleaning the outside of a casement above the ground floor generally means a ladder or a long-handled squeegee and some optimism.
Local context
How this applies in Decatur, IL
Every article here is written from window work done in Decatur and Macon County in central Illinois, so the numbers reflect local labour, permit and material costs rather than a national average. Your own job can land either side of them depending on access, the condition of what is already there, and the materials you pick — a written order specification carried forward from one round into the next, a low-emissivity coated triple-track storm panel hung over sound original sash, constant-force stainless balances kept on one system across an entire house.
The way to turn any of this into a real answer is to have someone look at your actual situation. The free estimate is free, itemized and written down, with no deposit and no obligation. Call (844) 511-2320 or start on the Decatur IL Windows homepage.
Areas Decatur IL Windows covers
Decatur first, then the surrounding communities of Macon County in central Illinois. Each has its own page with local detail rather than a copy of this one:
- Forsyth, IL — Macon County, population 3,734
- Mount Zion, IL — Macon County, population 6,019
- Long Creek, IL — Macon County, population 1,261
- Harristown, IL — Macon County, population 1,310
- Warrensburg, IL — Macon County, population 1,110
- Argenta, IL — Macon County, population 913
Or jump to the full list of Decatur services.
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The Decatur IL Windows Team
Licensed window pros in Decatur, IL
Written by the Decatur IL Windows team — licensed, insured window pros serving Decatur, IL and the surrounding area.