Better Budget: Draught Proofing

Draughts are one of the most overlooked sources of heat loss in New Zealand homes. Up to 25% of winter heat loss from existing houses is caused by air leakage, and windows and doors can account for up to 40% of total heat loss. The good news is that draught proofing is one of the cheapest and most accessible home improvements available, with most solutions costing under $50 and requiring no special skills.

Finding the Draughts

Before you start sealing, you need to identify where cold air is entering your home.

If you can see light shining through a closed door or around window frames, cold air is definitely getting in. On a windy day, hold your hand near window and door edges to feel for air movement. Another test is to close a window on a business card placed at the top between the frame and sash. If the card falls out or pulls out easily, the seal is inadequate.

Common draught sources include gaps around exterior doors, worn window seals, gaps around pipes and cables entering the house, open fireplaces without dampers, ceiling downlights without covers, and gaps in flooring where floorboards meet walls.

Door Draught Solutions

External doors are often the biggest culprits for heat loss.

Door sweeps and brush strips attach to the bottom of doors to seal the gap between door and floor. These cost $15 to $30 and take 15 minutes to install with basic screws or adhesive. Look for adjustable styles that compensate for uneven floors.

Weatherstrip tape seals gaps around door frames. Self adhesive rubber or foam strips cost $10 to $20 for a five metre roll, enough for one or two doors. Apply to the frame where the door closes against it, creating compression when the door shuts.

Door snakes or draught excluders are fabric tubes filled with sand or rice that sit against the door bottom. These are the simplest option, costing $10 to $20, but must be moved each time you open the door.

For doors with glass panels, check the glazing seals. Older doors often have deteriorated rubber seals that allow significant air leakage.

Window Draught Solutions

Windows can be sealed using several approaches depending on their condition and your budget.

Adhesive foam tape is the cheapest option at $5 to $15 per roll. Apply around the window frame where the sash meets when closed. Foam compresses to fill gaps but deteriorates after one to two years and needs replacing.

V seal weatherstrip is a more durable option made from vinyl or metal. It costs $10 to $20 and lasts longer than foam. Apply to the channel where the sash slides, creating a seal without affecting window operation.

Window film kits involve applying clear plastic film over the entire window frame, then shrinking it with a hairdryer to create a tight seal. These effectively create secondary glazing for $20 to $40 per window. EECA reports that window film kits can reduce heat loss through windows by nearly half. They remain in place for the entire winter season and are removed in spring.

Replacing worn friction stays on hinged windows costs $20 to $40 per window for parts, plus labour if not DIY. Worn stays allow windows to move and create gaps even when closed.

Fireplace Draughts

Open fireplaces are major heat loss points when not in use. Warm air rises up the chimney, drawing cold air in through other gaps in the house.

Chimney balloons are inflatable plugs that block the flue when the fireplace is not being used. They cost $30 to $50 and are simply removed before lighting a fire.

Dampers can be retrofitted to existing flues by a professional for $200 to $400. These provide a permanent solution with a simple lever control.

If you never use your fireplace, consider having the flue permanently capped by a roofer, which prevents heat loss and keeps out rain and birds.

Other Draught Sources

Ceiling downlights in older homes often have gaps around the fitting that allow warm air to escape into the ceiling space. Downlight covers cost $15 to $25 each and install from above in the ceiling space. Note that not all downlights are compatible with covers due to heat concerns, so check specifications.

Power points and switches on external walls can leak air. Foam gaskets designed to fit behind the cover plate cost only $1 to $2 each and take seconds to install.

Floor gaps where floorboards meet walls or around pipes can be sealed with flexible sealant. A tube of suitable sealant costs $10 to $15.

Cost Versus Savings

Draught proofing delivers modest but real savings. According to Meridian Energy, closing curtains before dark and using draught proofing can save $80 to $90 per year in heating costs.

A comprehensive DIY draught proofing effort for doors, windows, and minor gaps typically costs $50 to $150 in materials. At savings of $80 to $120 per year, payback occurs within one to two years, with benefits continuing for many years afterward.

The non financial benefits are equally valuable. A draught free home feels noticeably warmer at the same thermostat setting, and many people find they can reduce heating somewhat while maintaining comfort.

Healthy Homes Standards for Landlords

If you own rental property, draught stopping is a legal requirement under the Healthy Homes Standards. Since July 2021, landlords must stop unreasonable gaps or holes in walls, ceilings, windows, skylights, floors, and doors that cause noticeable draughts.

This includes ensuring all exterior doors and windows close properly and have functional latches, replacing broken or cracked window panes, and blocking chimneys if not in use.

Non compliance can result in penalties, and tenants can apply to the Tenancy Tribunal if draught stopping standards are not met.

Practical Tips for Best Results

Apply weatherstrips when the temperature is moderate, as extreme cold affects adhesive. Clean surfaces thoroughly with methylated spirits before applying adhesive products.

Check your work by repeating the business card test or feeling for air movement after installation. Adjustment is often needed to get seals positioned correctly.

Remember that some ventilation is necessary for healthy indoor air quality. Draught proofing should eliminate unwanted air leakage, not seal the house completely. Kitchen and bathroom extractor fans and intentional ventilation systems should remain functional.

Warmth That Costs Almost Nothing

Draught proofing is perhaps the most accessible energy improvement for any homeowner or renter. Most solutions require no special tools, take minutes to install, and cost under $20 each. The combined effect of sealing doors, windows, and minor gaps creates a noticeably more comfortable home.

Unlike major renovations or appliance upgrades, draught proofing is something you can start today with a trip to the hardware store.