Single-hung
Only the bottom sash moves; the top sash is fixed. The budget cousin of the double-hung.
What it means for you
The cheapest operable style, with one fewer moving part to fail — a legitimate value pick. The trade-off is you can't tilt the top sash in to clean it from inside upstairs. It is not rated as leakier than a double-hung; install quality matters more than the count of moving sashes.
Where you'll see it
Builder-grade and rental quotes; often the “starting at” price in an ad.
Don't be fooled
“Upgrade to double-hung” buys tilt-in cleaning of the top sash, not better energy — decide by whether you'll ever clean that top sash from outside.
Related terms
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