Draughtproofing and insulation to keep warm this winter

Draughts can make your home far less comfortable than it should be in winter, and drive up your energy use.

For Bellbrae residents Allan and Gail Roberts, the chill in their weatherboard home used to be unbearable in winter.

“Friends could see their breath when they stayed in the spare room,” says Allan. “It was so cold.”

He and Gail had to run their wood heater for around eight months of the year, “often for 24 hours a day,” to keep the place comfortable, and in summer they needed their reverse-cycle air conditioner to stay cool.

Now, after renovating the house to one of the highest international standards for airtightness and insulation, the house is “very pleasant to live in” with energy bills of around $160 per quarter. The internal temperature now stays around 22 to 24 °C year-round, with very little heating and no cooling.

The house was relocated to the coastal site by the previous owner some years before the couple bought it, hauled up from Melbourne on the back of a truck. “The owner before us was very thorough, reblocking and replastering the home when it got here, but he didn’t put any insulation in at all.”

With plans for a Solar PV system to lower their bills as they headed into retirement, they knew there was no point getting a system while the house wasted so much energy.

Their builder son Dale, with a keen interest in the international Passive House system and energy efficient building, upgraded the house, which is now one of the first renovations in Australia to meet the Passive House standard for airtightness and insulation.

The existing wall, ceiling and underfloor spaces were insulated, with Gutex insulative timber fibre board installed over the existing weatherboards. The entire building was wrapped in a vapour-permeable membrane and re-clad in a combination of fibre-cement weatherboards and Colorbond.

Warm air in the home can be lost through glass so the couple installed triple-glazed windows to greatly reduce heat loss through the home’s large windows.

Renew household efficiency expert Lance Turner says that with triple and even double-glazed windows beyond the budget of many households, there are many simple retrofits that can make a difference to energy use at home.

“Secondary glazing products exist (acrylic ‘window’ sheets) that can be added to windows to create an insulating airgap on the glass, much like double-glazing, or you can add a transparent window film to the glass to reduce heat loss.”

Lance says there are many reasons to seal gaps in a home. “The first is to keep conditioned air where it belongs inside the home. This reduces energy use for heating and cooling and bills, but there can be other negative effects of excessive air leakage that may not be immediately obvious, such as excessive dust or noise entering the home.”

For most people, the easiest job to tackle, and the one with the greatest effect, is to seal the gaps around windows and doors where they fit into their frames.

“If you have a newer home with windows in good condition, then they should have decent quality seals already fitted and you may not need to do anything. But for anyone in an older home with older windows, there will most likely be no seals at all.”

Lance says there are other, less obvious sources of draughts at home. “One source comes from gaps in and around appliances and fittings. Exhaust fans in kitchens and bathrooms are designed to flow large amounts of air easily, so if they aren't sealed when not running, that tendency to allow airflow can continue.”

One option is to add a draught seal which simply sits on top of a ceiling-mounted exhaust fan and opens and closes automatically. For ducts that are not being used at the moment, such as evaporative air conditioners, you can close them off temporarily with a duct cover.

Basic draught sealing requires no special skills, but if you are new to DIY, there are a few places that can help, including the Sustainability Victoria website.

If you think you may have leaks but don't have the time to find them (or are not the handy person type), you can employ companies that are well versed in how to find leaks, what to do about them and how to fill that ‘hole in your wall’.

Draught-proofing and insulation go hand-in-hand, so make sure your home has insulation in the ceiling, and the floors and walls if possible, too, before investing in a Solar PV system.

For Allan and Gail Roberts, they are very “pleased with the huge improvement to their comfort after insulating and draught-proofing the home to such a high standard.

“Our energy use is low, so the next step is to add a battery system to our solar to go off-grid in the next few years and have no more energy bills.”