Draught Sealing: The Low-Cost Upgrade That Lifts Comfort and Your Rating

If your home feels cold in winter no matter how high you push the heater, or warm air seems to vanish as fast as you make it, draughts are often to blame. Sealing them is one of the cheapest upgrades you can make, and it pays back in comfort, lower bills and a better thermal performance result.

Here is a practical look at where draughts come from, why air leakage matters, and how reducing it helps a NatHERS assessment.

What a draught really is

A draught is uncontrolled air movement in and out of your home through gaps and cracks. In winter, warm air you have paid to heat escapes while cold air sneaks in. In summer it works in reverse. This constant leakage, known as air infiltration, makes your heating and cooling work harder for a worse result.

The frustrating part is that draughts are usually invisible. A home can look perfectly finished and still leak air through dozens of small gaps that add up to the equivalent of leaving a window open.

Where draughts come from

Air leakage tends to concentrate at the same handful of weak points in most homes:

• Gaps around doors and windows. Worn or missing seals, and gaps where frames meet the wall, are classic culprits.
• Under external doors. The gap at the bottom of a door is an obvious and easy leak to fix.
• Downlights. Older recessed downlights can have openings into the roof space, letting conditioned air escape upward.
• Exhaust fans. Bathroom and kitchen fans without proper backdraught dampers can leak continuously when not in use.
• Wall vents and old vents. Vents installed for older heaters or appliances may no longer be needed but still leak.
• Service penetrations. Gaps where pipes, cables and ducts pass through walls, floors and ceilings.
• Floorboards and skirtings. In homes with suspended timber floors, gaps between boards and at skirtings can draw cold air from underneath.

Why air leakage hurts comfort and energy

Air leakage causes problems in a few ways at once:

• It steals your conditioned air. Every bit of warm or cool air that leaks out has to be replaced, which costs energy.
• It creates cold spots and chilly draughts. Even if the room is technically warm, moving air across your skin feels cold, so you turn the heater up.
• It undermines your insulation. Insulation slows heat moving through solid materials, but it does little to stop air rushing through a gap. The two need to work together.
• It can bring in moisture and dust. Uncontrolled air can carry humidity and outdoor particles into the home.

Simple ways to seal draughts

Most draught sealing is low cost and within reach of a confident homeowner, though some jobs are better left to a tradesperson.

One important caution: a home still needs some fresh air and, critically, safe ventilation for any gas appliances and flueless heaters. Never seal vents that serve combustion appliances without professional advice. When in doubt, ask. Our team can point you in the right direction through our contact page.

How reduced infiltration helps your NatHERS rating

NatHERS software models how heat moves into and out of a home, and air leakage is part of that picture. A home that leaks less air holds onto conditioned air better, which reduces the heating and cooling energy the model predicts. That can translate into a stronger star result.

It works the other way too. A home with generous, leaky construction can struggle to reach its target no matter how good the insulation looks on paper. Sensible draught sealing and well detailed junctions help the design perform the way it is meant to.

It is worth saying that the benefit depends on the home. A newer, tightly built house may have less to gain than an older, draughty one. Our assessors can advise where sealing is likely to move the needle on your particular project.

A sensible order of attack

• Start with the big, obvious leaks: external doors and worn window seals.
• Move to the roof space connections, especially downlights and exhaust fans.
• Seal service penetrations and any redundant vents, with safety in mind.
• Finish with smaller gaps at skirtings and floors.

Tackling leaks in this order means you fix the worst offenders first and feel the difference quickly.

Frequently asked questions

Can draught sealing make a home too airtight? A home needs some fresh air, and gas or flueless appliances need safe ventilation that must never be blocked. Sensible sealing targets unwanted leaks while keeping required ventilation in place. If you are unsure, get advice before sealing vents.

How much will draught sealing improve my rating? It depends on how leaky the home is to begin with and how it is built. An older draughty home usually has more to gain. Our assessors can model the likely effect for your project.

Is draught sealing worth doing in a renovation? Yes. Renovations are a great chance to seal gaps while walls, floors or ceilings are open and access is easy.

Building or renovating in NSW? Get a fast, fixed-fee quote from our HERA-registered assessors.