That foggy window is not just annoying. It is costing you money every single month.
The fog means the window’s airtight seal has failed. Argon gas has leaked out. Now your window is just a single-pane of glass. Heat escapes in winter. Cool air escapes in summer. Your HVAC system works harder.
But do you need a full window replacement? Or can you repair it? In this guide, we compare repair versus replacement costs. We show you clear decision criteria. And we explain why proper flashing and sealing matters more than the window brand.
Signs You Have a Window or Door Problem
Look for these common issues around your home.
| Problem | Likely Cause | Repair or Replace? |
|---|---|---|
| Fog between glass panes | Failed seal on insulated glass | Repair (replace glass unit) |
| Drafts around edges | Failed weatherstripping or sealant | Repair (re-seal) |
| Condensation between panes | Failed seal plus humidity | Repair (replace glass) |
| Rotting wood frame | Long-term water exposure | Replace |
| Cracks in glass | Impact or thermal stress | Repair (replace glass) |
| Sticking or jamming | Building settlement or warping | Varies (adjust or replace) |
| Windows 15-20+ years old | End of useful life | Replace |
| Failed seals in multiple windows | Age-related degradation | Replace all |
| Visible gaps around the frame | Missing or failed flashing | Repair (re-flash and seal) |
| Water stains on interior wall | Active leakage through frame | Replace + investigate wall |
When to Repair (And Save Money)
Repairing is often the smarter choice. Here are the situations where repair makes sense.
Single Window with Failed Seal
A foggy window almost always means a failed insulated glass unit (IGU). A professional can remove the glass panel, measure it, and install a new sealed unit. The cost is 200to500 per window. Full replacement costs 1,500to3,000. Repair saves 70-80%.
Drafty Windows with Good Frames
If your window frame is sound but you feel cold air around the edges, the weatherstripping or sealant has failed. A re-seal with professional-grade silicone or hybrid sealant costs 100to300 per window. This restores energy efficiency for 5-10 years. Read our Caulking & Sealant Repair guide.
Broken Hardware or Crank Mechanisms
A window that will not open or close properly often just needs new hardware. Parts cost 20to100. Labor is 1-2 hours per window. This is much cheaper than a full replacement.
When to Replace (The 5 Rules)
Replacement is expensive. But sometimes it is necessary. Replace your windows or doors if:
Rule 1: The Frame is Rotted or Damaged
Wood rot is like cancer. You cannot repair it partially. The rot will return. A rotted frame means full replacement. Vinyl frames that are cracked or warped also need replacement.
Rule 2: The Windows Are 20+ Years Old
Window technology has improved dramatically. Old single-pane windows have an R-value of 1. Modern triple-pane windows have R-values of 5-7. The energy savings alone often justify replacement.
Rule 3: You Have Condensation Between Multiple Panes
One failed seal is a repair. Five failed seals in the same house means the windows have reached the end of their lifespan. The seals are failing due to age, not defect.
Rule 4: The Window is Leaking Actively
If water is coming through the frame and damaging your interior walls, replacement is urgent. But also investigate whether the flashing was installed correctly. Poor installation of a new window causes the same problem.
Rule 5: You Want Major Energy Savings
New windows can reduce heating and cooling bills by 15-30%. They also reduce outside noise. For some homeowners, these quality-of-life improvements are worth the investment.
The Importance of Proper Flashing and Sealing
Here is an uncomfortable truth. A 3,000premiumwindowinstalledpoorlywillleak.A600 budget window installed perfectly will stay dry for 20 years. The installation matters more than the product.
Critical Components of Good Installation
- Head Flashing: A metal or plastic barrier above the window. It directs water outward, not into the wall.
- Sill Pan Flashing: A pre-formed pan at the bottom of the rough opening. It catches any water that gets behind the window and directs it out.
- Self-Adhered Membrane: A rubberized membrane that seals the rough opening before the window goes in.
- Backer Rod and Sealant: Proper depth of foam backer rod. High-quality hybrid or silicone sealant on the exterior perimeter.
Many contractors skip these steps to save time. Do not hire them. For professional installation, see our Windows & Doors Installation services.
Repair vs Replacement Cost Comparison
Here is a realistic cost breakdown for the Greater Toronto Area.
| Scenario | Repair Cost | Replacement Cost | When to Choose |
|---|---|---|---|
| Foggy single window | 200−500 | 1,500−3,000 | Repair (save 70-80%) |
| Drafty window, good frame | 100−300 | 1,500−3,000 | Repair |
| Rotted wood frame | Not possible | 2,000−4,000 | Replace |
| Multiple failed seals (5+ windows) | 1,000−2,500 (repairing seals) | 7,500−15,000 | Replace (costs similar over 10 years) |
| Sticking door, good condition | 150−400 (adjust or plane) | 2,000−5,000 | Repair |
| Door with water damage at threshold | Not possible | 2,500−6,000 | Replace |
Energy Savings Calculation Example
Let us do the math for a typical Toronto home with 15 older windows.
- Current monthly heating bill (winter average): $300
- After new windows (20% savings): $240
- Monthly savings: $60
- Winter months (6 months): $360 saved per year
- Plus cooling savings (summer): ~$100 saved per year
- Total annual savings: $460
New windows for 15 openings cost $22,500 installed. Simple payback period: 49 years. That is not good.
But if you also get improved comfort, less noise, and higher resale value, the math changes. Some homeowners accept a 15-20 year payback for these benefits.
For repair, a 300re−sealjobpaying60/month in energy savings pays back in 5 months. That is excellent.
Frequently Asked Questions
Q1: Can I replace just the glass instead of the whole window?
A1: Yes, for most modern windows. A glass shop can measure and install a new insulated glass unit (IGU). Cost is 200−500. The frame stays in place.
Q2: How long do new windows last?
A2: Vinyl and fiberglass windows last 20-40 years. Wood windows last 15-30 years with good maintenance. Aluminum windows last 30-50 years but conduct heat.
Q3: Does new window installation require a permit in Toronto?
A3: Replacing existing windows in the same opening does not usually need a permit. Changing the size or location of the opening does. Check with the City of Toronto.
Q4: What is the best season for window replacement?
A4: Spring to fall is best. Winter work is possible but uncomfortable. Cold temperatures affect sealant curing times.
Q5: Should I repair or replace windows before selling my house?
A5: Replace only if they are visibly failing (foggy, rotten, leaky). Repairs improve function without the high cost. Most home buyers expect functional windows, not brand new ones.
Conclusion
Foggy, drafty windows waste energy and money. But you do not always need full replacement. A single failed seal is a 300repair,nota3,000 replacement. Follow our 5 rules. Repair when frames are good and windows are under 20 years old. Replace when frames are rotten or multiple seals have failed.
Are your windows drafty or foggy? Do your doors stick or leak? Contact Kavern Restoration today. We offer Windows & Doors Installation and Caulking & Sealant Repair. Ask for a free inspection and honest advice on repair versus replacement.