When the temperature drops and the power bill rises, much of the heat loss in New Zealand homes happens through small gaps around doors and windows. Sealing these gaps is one of the simplest and most affordable ways to keep your home warmer and reduce energy use. With a few basic materials and a bit of time, you can make a noticeable difference to both comfort and efficiency.

Why sealing makes a difference

Even tiny draughts can have a big impact. When warm air escapes and cold air seeps in, your heating system has to work harder to maintain a comfortable temperature. That means higher energy consumption and more carbon emissions.

Good sealing can:

• Reduce heat loss by up to 10–15% in older homes.
• Improve comfort, by cutting down on draughts and cold spots.
• Lower outside noise, especially in busy urban areas.
• Protect doors and windows, helping them last longer by keeping out moisture and dust.

How to check for draughts

You don’t need special tools to find leaks – a few simple tests will do:

• Candle test: Hold a lit candle near the edge of a window or door. If the flame flickers, air is moving through a gap.
• Hand test: On a cool day, run your hand along the frame. If you feel a chill, there’s likely a leak.
• Paper test: Close a piece of paper in the door or window. If it slides out easily, the seal isn’t tight enough.

Choosing the right sealing strip

There are several types of weatherstripping, and the best choice depends on the size of the gap and the material of your door or window.

• Rubber (EPDM) strips – flexible, durable, and suitable for most doors and windows.
• Foam strips – inexpensive and easy to install, but they wear out faster.
• Silicone seals – very elastic and ideal for uneven surfaces.
• Brush seals – great for external or sliding doors where there’s more movement.

Measure the gap before buying. A strip that’s too thick can stop the door or window from closing properly, while one that’s too thin won’t seal effectively.

Step-by-step guide

1. Clean the surface. Remove old seals, paint flakes, and dust. Use a scraper and a bit of methylated spirits if needed.
2. Measure and cut. Measure the sides to be sealed and cut the strip to length.
3. Apply the strip. Most have a self-adhesive backing. Press it firmly along the edge, starting from the top and working down.
4. Check the fit. Close the door or window to make sure it still shuts smoothly.
5. Inspect regularly. Seals wear over time – check them every year or two and replace if needed.

Extra tips for saving energy

• Seal the letterbox flap with a brush strip or an internal cover.
• Insulate the attic hatch, as warm air often escapes upwards.
• Close curtains or thermal blinds at night to keep heat in.
• Consider double glazing if your windows are old – it’s a bigger investment but offers major energy savings.
• Use draught stoppers along the bottom of doors for quick, low-cost protection.

A small effort with big rewards

Sealing doors and windows is a classic DIY project that pays off quickly. It doesn’t require special skills or expensive tools, yet it can make your home warmer, quieter, and more energy-efficient. In a country where weather can change quickly and energy costs are rising, it’s a simple step towards a more comfortable and sustainable New Zealand home.