Double Pane Windows
Two panes of glass, a sealed layer of argon and a Low-E coating. Double pane windows are the smart standard for Ontario homes. Here are honest prices, how they compare, and what to do when the glass fogs up.
The Basics
What Is a Double Pane Window?
A double pane window has two layers of glass sealed into one unit, called an insulated glass unit. A spacer runs around the edge to hold the panes apart, and the gap is filled with argon gas, which slows heat loss better than air.
A thin Low-E coating on one pane reflects heat back into the room in winter and blocks sun heat and UV in summer. A warm-edge spacer keeps the glass edge warmer, so less condensation forms there.
You may also hear double glazed or dual pane. They all mean the same thing. At WindowFixers.ca every standard window we install is double pane with Low-E and argon, and we offer triple pane where it truly pays off.
Benefits
What Double Pane Windows Do for Your Home
Plain facts, no inflated savings promises.
A Warmer Inside Pane
The sealed gas layer keeps the glass you touch far warmer than single pane, so rooms feel less drafty near the window in January.
Less Winter Condensation
A warmer inside pane means far less frost and water on the glass at normal indoor humidity. Very high humidity can still fog any window.
Quieter Rooms
Two panes and an air gap cut everyday street noise compared with one pane. For a busy road, laminated glass helps more than a third pane.
Low-E Comfort in Summer
The Low-E coating reflects heat and blocks most UV, so floors and furniture fade less and south rooms stay cooler.
ENERGY STAR Ready
A good double pane unit with Low-E and argon meets the ENERGY STAR Canada level for our zone (U-factor 1.22 or lower).
Best Value per Dollar
Double pane gives most of the comfort gain of triple pane for less money and less weight on the sash and hardware.
Side by Side
Single vs Double vs Triple Pane
Typical values for vinyl windows in Ontario. Exact numbers depend on the product label.
| Single pane | Double pane | Triple pane | |
|---|---|---|---|
| Layers of glass | 1 | 2 | 3 |
| Typical U-factor (W/m²·K, lower is better) | About 5.0–5.8 | About 1.2–1.6 (good units 1.22 or lower) | About 0.7–1.0 |
| Inside glass in a cold snap | Very cold, frosts easily | Cool, rarely frosts | Close to room temperature |
| Noise | Poor | Good | Slightly better |
| Weight | Light | Standard | About 40–50% heavier |
| Price, standard casement installed | Not sold for homes | $500–$1,000 | $590–$1,180 |
| Best for | Sheds and garages | Most rooms in most homes | North walls, cold rooms, very noisy sides |
Torn between two and three panes? See our triple pane windows guide and the blog triple pane vs double pane: is it worth the upgrade?
Prices
How Much Do Double Pane Windows Cost?
Supplied and installed, retrofit, standard sizes, ENERGY STAR vinyl with Low-E and argon. Triple pane shown for comparison.
| Window | Double pane | Triple pane |
|---|---|---|
| Casement or awning | $500–$1,000 | $590–$1,180 |
| Single or double hung | $500–$1,000 | $590–$1,180 |
| Slider | $450–$950 | $530–$1,120 |
| Picture (fixed) | $400–$900 | $470–$1,060 |
| Bay or bow | $2,500–$6,000 | $2,950–$7,080 |
| 10 standard windows | $6,000–$14,000 | $7,100–$16,500 |
| New sealed glass only (frame kept) | Typical GTA range about $350–$700 | Depends on sash depth |
Full-frame replacement adds roughly 25%. Final price is set after a free in-home measure.
Size and style
Bigger glass and opening styles (casement, hung) cost more than fixed picture units.
Retrofit or full-frame
Full-frame replacement, needed when the old frame is rotten, adds roughly 25%.
Glass options
Laminated, tinted or obscure glass and grilles add to the base price.
Access and finishing
Upper floors, brick returns, new trim and exterior colour all change the total.
Want a number for your house?
Use our window replacement cost calculator for a quick estimate by style and count.
Honest Savings
What You Save Depends on Where You Start
From single pane: this is the biggest step you can take with windows. The inside glass goes from icy to cool, drafts near the window drop and frost on the glass mostly stops. Heating savings are real, but the amount depends on your house, fuel and how many windows you change.
From an old double pane: savings are smaller. The gains come from Low-E, argon, a warm-edge spacer and, above all, a tight new seal around the frame. Many people replace for comfort, drafts and fogged glass rather than the bill.
Be careful with ads that promise 25–30% off your heating bill or a 5-year payback. Windows are only one part of a home's heat loss. For a worked example with real numbers, see our energy efficient windows guide.
Seal Failure
Fog Between the Panes? Glass, Sash or Whole Window
If you see haze or droplets between the two panes, the edge seal has failed and the argon has leaked out. It cannot be cleaned and it will not go away.
That does not always mean a new window. If the frame and sash are sound, new sealed glass is often the cheapest real fix. Here is how we decide.
| What you see | Best fix | Typical cost | Note |
|---|---|---|---|
| Frame and sash are solid, only the glass is foggy | Replace the sealed glass unit only | Typical GTA range about $350–$700 per unit | Cheapest real fix. Check your old warranty first; many cover seal failure. |
| Sash is warped, hardware worn or drafty, glass foggy | Replace the sash or the whole window | $400–$1,000 for a new double pane window | New glass in a leaky sash still leaves you with a cold, drafty window. |
| Many windows foggy, frames 20+ years old | Plan full window replacement | 10 windows about $6,000–$14,000 | Seals in the same batch tend to fail one after another. |
| Water only on the room side of the glass | Not a seal problem: lower indoor humidity | Usually $0 | Run fans, open blinds and keep humidity around 30–40% in winter. |
Lifespan
How Long Do Double Pane Windows Last?
The frame often outlives the glass seal. Here is what to expect.
How long the seal lasts
A well-made sealed unit usually lasts about 15–25 years. Cheap units and poor installs can fail in under 10.
Why seals fail
Daily heating and cooling flexes the seal. Sun on dark frames, water sitting in the sill, and a sash that does not drain all speed it up.
What failure looks like
A haze, streaks or droplets between the panes that you cannot wipe off from either side. The gas is gone and the unit insulates like air.
Why defogging is not a fix
Drilling and drying the unit can clear the haze, but it does not put the argon back or reseal the edge. The window stays less efficient.
Room by Room
Where Double Pane Is All You Need
Bedrooms and living rooms on south, east or west walls
Sun helps in winter, and double pane with Low-E keeps them comfortable year round.
Main floor rooms on quiet streets
Two panes already block normal neighbourhood noise well.
Basements
Small windows and below-grade walls mean a third pane adds cost for little gain.
Large sliders and patio-size glass
Weight matters on big sashes. Double pane keeps them easy to open and kinder to hardware.
Cold north wall, a room over the garage or a busy road? That is where triple pane earns its price. Not sure which glass you need? Read our window glass guide.
How It Works
Our Double Pane Window Installation
Free In-Home Measure
We look at every window, check frames for rot and tell you where double pane is enough.
Clear Written Quote
Price per window, retrofit or full-frame, glass options and the warranty in writing.
Clean Installation
Our own crews remove the old units, set, shim and insulate the new ones, then seal inside and out.
Final Check
We test every sash, lock and screen and clean up before we leave.
Why WindowFixers.ca
Family-Owned, 10+ Years
A local Newmarket company serving the GTA, York Region and up to Barrie.
Our Own Crews
8,700+ clients served by licensed, insured installers we employ, not subcontractors.
Lifetime Transferable Warranty
ENERGY STAR vinyl windows with Low-E argon glass and a warranty that moves with the house.
Honest Advice
If new glass in your old frame is the better deal, we will say so.
Double Pane Windows FAQ
Straight answers to the questions Ontario homeowners ask us most.
Get a Free Double Pane Window Quote
Tell us how many windows you have. We will measure for free and give you a clear written price.