What Is a Sealed Unit?
A sealed unit (also called an IGU or Insulated Glass Unit) is the glass portion of your window—two or three panes of glass separated by spacers and sealed together with an insulating gas (usually argon) in between. This is what provides your window's thermal insulation.
When the seal fails, moisture enters between the panes, causing that familiar foggy, cloudy, or streaky appearance. The good news? You can replace just the sealed unit without replacing the entire window frame.
Signs Your Sealed Unit Has Failed
- Fog or condensation between the glass panes (not on the surface)
- Cloudy, hazy appearance that won't wipe clean
- Visible moisture droplets inside the glass
- White residue or mineral deposits between panes
- Distorted view through the window
- Ice forming between panes in winter
Why Seals Fail
Sealed units typically last 15-25 years, but several factors can cause premature failure:
- Age: Seals naturally degrade over time
- Sun exposure: South and west-facing windows fail faster
- Temperature extremes: Ottawa's -30°C to +35°C swings stress seals
- Poor quality: Some manufacturers use inferior sealants
- Improper installation: Glazing issues cause premature failure
Sealed Unit Replacement vs. Window Replacement
| Factor | Sealed Unit Replacement | Full Window Replacement |
|---|---|---|
| Typical Cost | $150-$400 | $500-$1,500+ |
| Timeline | 1-2 weeks | 4-8 weeks |
| Disruption | Minimal (30-60 min) | Significant (interior/exterior work) |
| Results | Clear glass, restored insulation | Clear glass, new frame/hardware |
| Best For | Good frames with failed glass | Damaged frames or major upgrades |
Our Sealed Unit Replacement Process
Measure
Technician visits to measure and assess frame condition.
Fabricate
Custom IGU built in our facility to exact specs.
Install
Old unit removed, new unit glazed and sealed.
Warranty
10-year manufacturer warranty on sealed units.
Upgrade Options
When replacing your sealed unit, you can upgrade to better glass technology:
- Low-E coating: Reflects heat to improve energy efficiency
- Argon gas fill: Better insulation than air-filled units
- Triple pane: Maximum insulation (where frame allows)
- Tinted glass: Reduce glare and heat gain
- Laminated glass: Enhanced security and sound reduction
Frequently Asked Questions
The process typically takes 1-2 weeks total. The initial measurement visit takes about 15 minutes. Fabrication takes 5-10 business days. Installation takes 30-60 minutes per window.
Most vinyl, aluminum, and wood windows can have their sealed units replaced. We'll assess your frame condition during the measurement visit. If the frame is damaged, warped, or rotted, full replacement may be recommended.
Our sealed units come with a 10-year manufacturer warranty against seal failure. We also provide a 2-year workmanship warranty on installation.
Yes. We match glass type, thickness, coatings, and tint to your existing windows. In most cases, the replacement is indistinguishable from adjacent windows.