Prepare Your Windows in Summer

How one decision can save you from cold winters and rising bills

While it is +28°C outside and heating is the last thing you want to think about, now is actually the best time to take care of your windows. It may sound counterintuitive, but there is a simple explanation: replacing windows is not a one-day process, and Ottawa’s installation season is short. If you start now, your home will already be retaining heat by the first snowfall. If you wait until October, you may have to spend another winter with your old window frames.

Where does your heat go?

According to Natural Resources Canada, windows and doors may account for as much as 25–35% of the total heat loss in an average Canadian home during winter. In Ottawa, where the heating season is long and temperatures regularly fall below –20°C, this is not an abstract figure—it represents a significant portion of your monthly gas or electricity bill.

The problem is rarely the glass itself. More often, it is what happens around it: dried-out weatherstripping, a warped frame, or an air gap between the sash and the frame. The heat you pay for escapes through these invisible cracks without you even noticing.

You can easily determine whether your windows are the problem without calling a specialist. On a cold winter day, hold your hand close to the frame. If you feel cold air even though the window is closed, that is where the heat is escaping. Fogged or frost-covered glass on the inside, squeaking or sticking when opening, and visible gaps between the sash and the frame all point to the same conclusion: it is time to replace the window.

How does an insulated window actually work?

A modern energy-efficient window is much more than simply “double glazing.” It is an entire system.

Multi-pane glazing. There is a sealed air chamber between the panes. In high-quality windows, ordinary air is replaced with an inert gas—argon. Because argon conducts heat less efficiently, it keeps warmth inside the home much more effectively during winter.

Low-emissivity coating (Low-E). An ultra-thin metal layer, invisible to the eye, reflects infrared radiation back into the room. In summer, the same coating prevents excessive solar heat from warming the interior, so it works in both directions.

Warm-edge spacer. The metal spacer between the panes, which once acted as a “thermal bridge,” has been replaced in modern windows with a composite material known as a Super Spacer. This helps prevent the condensation and frost around the edges of the glass that many people remember from older windows.

The frame. Vinyl remains the most practical choice for the Canadian climate. It does not dry out, requires no painting, and can last for decades.

What should you look for when choosing windows for a Canadian winter?

For the Ottawa–Gatineau climate zone, experts recommend:

• Triple-pane windows filled with argon—the most efficient option—with an Energy Rating of ER 34; or double-pane argon-filled windows with an ER 34 rating. These are energy-efficient windows for homes expected to stand for many decades.

• ENERGY STAR certification for cold-climate zones B and C, confirming that the window has been tested specifically for Canadian winters rather than average climate conditions.

• A low U-factor—the lower it is, the better the insulation—and an appropriately selected Solar Heat Gain Coefficient (SHGC). For windows on the south and west sides of a home, a higher SHGC may be beneficial because it allows winter sunlight to provide free heat.

• The Energy Rating (ER), a Canadian rating system that evaluates three factors at once: heat loss, solar heat gain, and air leakage.

How much can you realistically save?

The figures are particularly convincing. For an Ottawa home where winter heating costs average between $2,500 and $3,500 per year, new windows can save several hundred dollars annually—and those savings continue year after year throughout the life of the windows.

Why should you act now?

Replacing windows is not only about reducing heating bills. It also means less street noise, no drafts near a child’s bed, no morning frost on the windowsill, and a completely different view—without worn-out frames clouded by age.

Summer is the only season when this work can be completed without rushing. You can schedule measurements, select a model, wait for the windows to be manufactured, and have them installed in comfortable weather instead of on a freezing November day.

In addition to windows, you may also want to replace or install new patio doors—also ENERGY STAR certified—entrance doors, garden doors, fire-rated doors with a 20-minute fire-resistance rating, and doors connecting the house to the garage.

When winter arrives, you will not have to hope that your old windows and doors will “somehow make it through.” Instead, you will know that your home will stay warm—and that you will be paying considerably less for that warmth.

Vitaliy Anufriyev
Window and door installation specialist with 25 years of experience
613-224-7887