Leaking Window Repair
Leaking window repair starts with one fact: a leaking or drafty window has a failed seal, not a failed window. We find where air and water get in and seal it — weatherstripping, caulking and insulation — without replacing the window.
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- All window types & brands
- Fully insured
- Price match
Signs You Need Draft & Leak Repair
Feeling a draft
Cold air you can feel near the window, curtains that move, or a room that's always chilly points to air leaks.
Water during rain
Moisture, dripping, or staining on the sill, wall, or floor after rain means water is getting past the seals.
Rising energy bills
Heating and cooling bills creeping up, or a furnace/AC that runs constantly, often trace to air leaking around windows.
Cracked or missing caulk
Visible gaps, shrunken or crumbling caulk, and flattened weatherstripping are the leak points themselves.
Find Your Leak
Air and water get in at a handful of places. Check them in this order:
- From above — roof or siding
- Meeting rail — gap at the lock
- Caulk joint — cracked, lets water in
- Weather seal — worn edges
- Sill joint — water gets under
- Worn weatherstripping — air slips past the edges of the sash.
- Meeting rail gap — sashes that no longer close tight at the lock.
- Failed exterior caulk — the joint between the window frame and the wall.
- Sill joint — water gets under or behind the sill.
- Above the window — flashing, siding or roof leaks. Water shows up at the window, but it isn't a window problem.
The first four are window repairs. Water coming from above the window is a roof or siding problem — we check for that first.
Not sure where the water comes from? Note when it appears, then send us a photo.
- Find drafts on a windy day by holding a lit candle or incense stick near the window edges.
- Note exactly where water shows up and when — it helps us find the real entry point.
If it's urgent — until we arrive
- Use removable rope caulk or window film as a temporary winter fix.
Window Leaks and Drafts Come From Failed Seals
A cold draft or a rainy-day leak feels like the window has failed. Almost always, though, the window is fine — it's the seals around it that have worn out, and seals are made to be renewed.
Every window depends on a system of seals to keep air and water out: weatherstripping between the moving sash and the frame, caulk around the exterior and interior perimeter, flashing and drip edge that direct rain away, and insulation in the hidden gap between the frame and the wall.
Over the years these dry out, crack, compress, and pull away — and northern Illinois's freeze-thaw winters and humid summers wear them down from both directions. When they fail, cold air pours in, warm air escapes, and rain finds its way past.
The fix isn't a new window — it's finding every leak point and re-sealing it. Because seals are consumable by design, re-sealing is normal maintenance that restores the window's air- and water-tightness for a small fraction of replacement cost.
Two problems, one repair
Drafts (air leaks) and leaks (water intrusion) often share the same failed seals, so we address both together.
Stopping the air leak improves comfort and cuts energy loss; stopping the water leak protects the frame, sill, and wall from the rot and staining water causes — the same damage our sill repair and rotted wood repair work exists to fix once water has been getting in for too long.
A window leak when it rains, water leaking around the window frame, or a window draft you can feel on cold days usually traces back to the same few places: worn weatherstripping, failed window caulk, or a sash that no longer closes tight.
Finding the real entry point comes first — sealing the wrong spot just moves the water somewhere else.
Not sure this is your problem? Use our window triage guide — pick the symptom and see the likely cause and cost. Related reading: Seasonal window maintenance calendarBasement window repairWindow problems home inspectors flag
How We Seal a Leaking or Drafty Window
Find the Leak Points
We locate every path air and water are taking — weatherstrip, caulk lines, perimeter gaps, glazing, and flashing above the window.
Replace Weatherstripping
Worn or missing weatherstripping between the sash and frame is replaced so the window seals tight when closed.
Re-Caulk & Insulate
Old caulk is removed and replaced, and the hidden gap between frame and wall is insulated where it's missing or thin.
Confirm It's Sealed
We check that the draft is gone and the window is water-tight — backed by our warranty.
Jobs that need a professional
- Caulking over a leak without finding its source — water gets trapped behind the new caulk.
- Leaks at the top of the window — they often come from the wall or roof above.
- Water inside the wall, on the ceiling, or staining below the window — possible hidden damage.
- Weatherstripping on double-hung sash channels — it is built into the sash and easy to damage.
Weatherstripping Replacement — and Leaks in Vinyl and Aluminum Windows
Weatherstripping is the flexible seal between the sash and frame. It flattens, cracks and falls out over the years, and a window that looks fine can leak air all around. Replacing it — matched to your window's profile, whether foam, felt, pile or rubber bulb — is one of the quickest fixes for a drafty window.
Leaks aren't only a wood-window problem. Vinyl windows most often leak at the frame corners, where welded joints crack, and where exterior caulk has failed. Aluminum sliders leak when the weep holes at the bottom of the track clog, so rainwater backs up inside. Each has its own fix — resealing corners, clearing weep holes, new caulk and weatherstripping.
Leaking Window Repair Cost
Minimum service visit: $150 — several small repairs in the same visit are covered by it.
Typical prices
Per window · typical local prices| Weatherstripping replacement | $100–$300 |
| Exterior caulk & reseal around the frame | $100–$350 |
| Alignment so the sash closes tight | $50–$500 |
Repair vs. a new window, per window
Drafts are the classic pitch for full window replacement — but the draft is coming from failed seals, not a fundamentally failed window.
Re-sealing restores air-tightness for a small fraction of replacement cost, and unlike most repairs, this one keeps working for you: by cutting the air leakage that makes your furnace and AC run harder, a sealing job can quietly lower your energy bills every month.
That combination — low cost, real comfort improvement, and ongoing energy savings — makes leak and draft sealing one of the highest-value window services there is. On older wood windows it also preserves the original window rather than replacing it.
Replacement only makes sense when a window is structurally failing across multiple areas at once, which is uncommon; we'll tell you honestly which applies and give you an estimate before any work begins.
Why northern Illinois windows leak
Sub-zero January nights shrink caulk and stiffen weatherstripping until it cracks, and wind across open farmland west of Huntley and Marengo drives air through every gap. In spring, wind-driven rain finds any caulk joint that failed over the winter — which is why leak calls peak in April.
Warranty on Sealing Work
Parts we don't make (cranks, balances, locks) carry only their supplier's warranty. Leaks from roofs, flashing or siding aren't window defects. Full warranty terms Read our reviews
Who does the work
- Our own technicians — no subcontractors.
- About 10 years in the trade, on every kind of window and door.
- The same people who give the estimate come back to do the work.
Make the repair last
- Replace foam or felt weatherstripping on basement and storage windows yourself.
Got a quote to replace these windows?
Send it to us before you sign. We'll tell you — free — whether a repair would solve it for less.
What Customers Say
"Local Window Service is amazing! We moved to our 20 year old home earlier this year, and during a heavy rain storm, we noticed a leak in one of the windows. LWS came out and fixed it at a reasonable cost. At my request, they proceeded to carefully inspect all of the many windows on all three floors of my home. They then provided an extremely reasonable estimate for repairing all windows. They did not try to take advantage of me-there were many windows where they said everything was fine. For the problem windows, they showed me the specific issues for each and every one, patiently taking the time to explain the issues. They were able to complete all window repairs in 2.5 days. The work was high quality/professional, and they took great care to ensure that everything was perfect before they left. I cannot recommend them highly enough-they will be my go to for all window issues moving forward!"
"Igor was very honest and explained the exact issue."
"Igor and his assistant did a great job repairing our water damaged window. They re-caulked all around the outside and replaced and painted the sill in under two hours. Extremely reasonable rates, friendly, and professional. I would highly recommend Igor and LWS Services!"
Leaking Window Questions
More Repairs for Sashes & Moving Parts
Draft & Leak Repair Near You
Based in Lake in the Hills — we do draft & leak repair in Lake in the Hills and 35+ nearby towns, within about 30 miles. Find yours:
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Tap a town to open its page. The dashed ring shows about 30 miles from Lake in the Hills.
Seal Out the Drafts.
Call, text, or send a photo. You'll know what's wrong and roughly what it costs — before anyone comes out.
★★★★★ 4.9 from 145+ reviews · 20-year glass warranty · Price match