Window Problems by Home Age
What typically fails on windows from each era — and whether it's worth repairing.
When your house was built tells you a lot about your windows — what they're made of, how they work, and what's likely to fail next.
Window technology changed decade by decade: from hand-built wood sashes on cords and weights, through aluminum sliders, to clad-wood casements and vinyl windows with sealed double-pane glass. Each generation has its own weak points. Find your home's era below.
In McHenry County, the biggest group is homes built in the 1990s and 2000s — Lake in the Hills, Huntley, Algonquin and much of Crystal Lake. Those windows are now 20 to 35 years old, which is exactly when glass seals, balances and cranks give out.
- Before the 1940s — wood double-hungs with cords and weights, single-pane glass in putty, wood storms.
- 1940s – 1960s — wood windows and early aluminum sliders, aluminum combination storms.
- 1970s – 1980s — early double-pane glass, clad-wood windows, crank-operated casements.
- 1990s – 2000s — clad-wood and vinyl windows with spring balances and sealed low-E glass.
- 2010s and newer — vinyl, fiberglass and clad windows with gas-filled low-E glass.
Each era has its own weak points — see what to check for yours below.
Window Problems by Era at a Glance
| Era & typical windows | What fails & what to do |
|---|---|
| Before 1940 Wood double-hungs with sash cords and weights, single-pane glass in glazing putty, wood storm windows. | Broken sash cords, painted-shut sashes, cracked glazing, rotted sills and sash bottoms. Usually excellent candidates for restoration — old-growth wood is very durable. |
| 1940s – 1960s Wood double-hungs and casements, early aluminum sliders, aluminum combination storms. | Rot on sills, worn aluminum rollers and latches, drafts, single-pane glass. Aluminum frames and solid wood are both very repairable. |
| 1970s – 1980s Wood and early clad-wood windows, first double-pane glass, casements with crank operators. | Foggy early glass units, stripped cranks, rot under cladding, worn weatherstripping. Glass units and hardware can be replaced; wood rebuilt. |
| 1990s – 2000s Clad-wood casements and double-hungs from major brands, vinyl windows, spring balances. | Foggy glass, failing balances and tilt latches, stripped casement cranks, rot at clad sash bottoms. Now 20–35 years old — prime age for part-level repairs. |
| 2010s and newer Vinyl, fiberglass and clad windows with low-E, gas-filled glass. | Early hardware failures, occasional seal failures, adjustment issues. Check the manufacturer's warranty first — then repair. |
What to Check for Your Home's Era
Before 1940
Raise and lower each sash: does it stay where you put it, or drop? That's usually a broken sash cord. Look at the glazing putty for cracks and missing chunks, and press a screwdriver into the sills and the bottom of each sash to find soft wood.
Check storm windows for broken glass and stuck panels. Paint on windows in homes built before 1978 may contain lead, so have it tested before any sanding or stripping.
1940s – 1960s
On aluminum sliders, check whether each panel glides or drags, whether the latch pulls it tight, and whether the tracks are bent or packed with grit. On wood windows from this era, the sills and sash bottoms are the first places to probe for rot. Single-pane windows here gain a lot from a working storm window.
1970s – 1980s
Look for fog between the panes of early double-pane units — seals from this era are well past their typical 15 to 25-year life. Turn every casement crank: stiffness or slipping means worn gears. On clad windows, press gently at the bottom corners of the sash for soft wood hiding under the cladding.
1990s – 2000s
The biggest group in our area. Check for foggy glass, sashes that won't stay up (worn balances), tilt latches that snap in the cold, and cranks that are stiff or strip. The bottom corners of clad sashes are again the place to check for hidden rot.
2010s and newer
Many parts may still be under the manufacturer's warranty, so check before paying for repairs. Problems on newer windows are usually adjustments: sashes that don't close evenly or locks that no longer line up.
How Long Window Parts Typically Last
- Insulated glass seals: typically 15 to 25 years.
- Balances, tilt latches and similar moving parts: typically 15 to 25 years.
- Vinyl frames: often 25 to 40 years.
- Wood windows: many decades — often a century — when paint and glazing are maintained.
When a part wears out, it can almost always be replaced on its own. See typical prices in our window repair cost guide.
Related repairs: Wood window restoration · Aluminum window repair · Vinyl window repair
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