There are smart and inexpensive tricks to trapping heat indoors.

When the weather’s cold, ten times more heat escapes through standard windows than through insulated walls. That means your mid-year heating bill is vanishing through the glass.

But there are quick and simple fixes to help block the cold, says Amber Chamberlain from environmental consultancy Ecovantage. “Just covering up your windows in winter helps stop heat loss.”

When it’s cold outside, warm air turns into a chilly draught as it draws near exposed glass. To cut the heat flow, you need to trap a layer of still air next to the window pane.

“Curtains and blinds need to fit snugly and to be heavy – the heavier the better,” she says. “A good rule of thumb is that the more light coming through, the more heat that’s also being transferred.” Go for curtains that stretch below and beyond the sides of the frame, touching the wall or floor, and install pelmets (seals above the curtain or blind) to stop air at the top. You can fashion temporary pelmets from anything that fits – try cardboard or a thick scarf.

If heavy drapes aren’t to your taste, Ms Chamberlain suggests honeycomb or cellular blinds as a good alternative. “They trap a small amount of air within the blind itself, which acts as an insulating layer, and they still allow light into the home.” It’s wise to avoid gappy vertical and Venetian blinds.

Kirsten Johnstone, from Eco Edge Architecture + Interior Design, maintains that with careful thought, window coverings can be attractive as well as functional. If you’re building your home, she recommends designing window frames to fit recessed blinds. “You can create a channel that holds the sides of the blind within the frame,” Ms Johnstone says. “I think that’s a good solution, rather than the voluminous curtains that remind me of my Grandma’s house.”

She also says that, for homebuilders and retrofitters alike, pelmets need not be eyesores. “A minimal approach would be a small, painted box above the window or within a frame recess, painted out so it matches the wall. Try not to attract attention to it.”

Another way to improve your windows’ performance is by retrofitting double-glazing. Ecovantage suggests that DIYers try Clear Comfort, a membrane taped to the frame and made taut by shrinking with a hairdryer. “It’s virtually invisible and traps a layer of air in between the film and window, á la double-glazing,” Ms Chamberlain says. A 10-metre kit costs only $180.

For the less handy, companies such as Magnetite and MagicSeal sell secondary acrylic panes that attach to your window frame using magnets. “This solution is much more permanent and durable than DIY film. It’s more expensive, but still a fraction of [the cost of] double-glazing,” says Ms Chamberlain. The cheapest option of all is recycled bubble wrap, stuck on with the smooth side facing the room. “The little bubbles are perfect mini double-glazing cells, so why not use it on your windows?”

See related article: Windows

Both owners and tenants can benefit from retrofitting their houses.

“If a landlord and a renter were in a conversation,” says Jessica Steinborner, from Moreland Energy Foundation. “I think they’d agree that we should do something about sustainability, and that our homes are a good place to start. But how do we actually get the changes to happen?”

It’s tricky to even begin that discussion: communication between landlords and tenants is often fraught and property managers don’t always help.

As a part of its Energy Efficient Homes Package, however, the Federal Government has given all parties a reason to get talking. Owners are now eligible for up to $1000 to install insulation and $1600 to replace electric hot water heaters with solar units.

Landlords can also get rebates on rainwater tanks and grey water setups, and claim tax deductions on eco-maintenance around their properties. What’s more, from May 2011, they’ll be required to reveal the dwelling’s energy performance at the point of lease.

These steps help reduce the so-called split incentives, whereby property-owners pay for big-ticket items, but tenants get the lower bills. Ms Steinborner argues that, in any case, owners do benefit from their investment. “It improves their property – not just the resale value, but also the ability to get long-term tenants. Renters understand that it will be a far cheaper and more comfortable house to live in.”

Moreland Energy Foundation organises free workshops for local renters who want to green their homes. The good news, Ms Steinborner says, is that people can slash their eco-footprints without altering their houses. “About 30 per cent of household energy use is related to behaviour; things like closing the curtains when the sun goes down, using external blinds in summer, shortening showers, washing clothes in cold water, setting thermostats correctly and turning lights off.”

Renters can also install compact-fluorescent light globes and choose efficient appliances without bothering the owner. But before they make other changes – including switching showerheads – they should get approval. “There are small things that often people won’t do because they’re worried about their tenure, and nervous about contacting their landlord,” Ms Steinborner says.

With energy and water prices rising, low-income renters are likely to be the first to suffer. Last year, a group of Melbournians started Just Change, an organisation dedicated to addressing these equity concerns. “We put up to $1800 worth of energy efficiency retrofitting into a house,” says Dougal McInnes, “and ask for up to a one-year rental freeze (in exchange).”

He says it’s been difficult to find homes where all parties are willing to be involved. “We’ve found that real estate agents are the key, both to gaining consent from the landlord and access to the tenants.” There’s a lesson for aspiring eco-friendly tenants and owners: get your property manager onside first.

For oodles more tips and information, browse Environment Victoria’s excellent Victorian Green Renters’ Guide. Also, check out Green Renters, a blog for environmentally conscious tenants.

Buying renewable energy is the fastest way to cut your eco-impact, but make sure you do your homework.

Half of an average household’s carbon dioxide emissions can come from electricity. That means you can slice your home’s carbon footprint in two simply by switching to 100 per cent GreenPower.

GreenPower is an accreditation program for renewable energy – electricity sourced from the sun, wind, water and waste. When you choose GreenPower, your retailer must buy enough new renewable energy into the grid to replace your old fossil fuel power use. Products that come with the scheme’s tick have been audited to make sure you’re getting what you pay for.

But which product is best? To help consumers cut through the spin, Total Environment Centre started Green Electricity Watch in 2002. The survey – also supported by Australian Conservation Foundation and WWF-Australia – assesses the eco-credentials of the companies and their products.

“All the retailers participate and they compete very fiercely to get a good ranking,” says Jane Castle, senior campaigner at Total Environment Centre. In the last survey, held in 2007, Origin Energy’s 100 per cent wind and solar products scored the most points (the full results are online).

If you’re thinking of making the switch, Ms Castle warns against swift deals offered by door-to-door salespeople, because they can lock you into contracts with only a low percentage of accredited GreenPower. “To actually make a difference, people should buy as high a percentage of GreenPower as they can afford.”

Generally, the higher the renewable energy content, the higher the price – but shop around because rates vary considerably among retailers. “When I switched to 100 per cent GreenPower I was nervous about getting a big bill,” says Ms Castle, “so I turned things off standby and put in compact fluorescent globes and my bill virtually didn’t change. This is not going to kill you at the bank. It might be worth one coffee a week or it might have no impact if you become really energy efficient.”

There’s one important catch to the GreenPower scheme. Although your personal footprint will come down if you buy accredited renewable energy, Australia’s overall emissions won’t.

Since the federal government signed onto the Kyoto Protocol (the global treaty limiting greenhouse gas emissions), any voluntary reductions made by individuals or businesses don’t get added on top of the pre-existing national target. Any cuts you make mean someone else will be permitted to pollute more. The proposed Carbon Pollution Reduction Scheme will work in a similar way.

“It means that the big polluters will have fewer restrictions put on them,” Ms Castle says. “We’re trying to get the government to recognise consumer action as additional, by retiring a Kyoto permit for every tonne of CO₂ reduced through GreenPower.”

Despite those concerns, Green Electricity Watch still recommends that people buy accredited renewable power, because it supports the industry and helps prepare for a low-emissions future. “We say, yes buy GreenPower, but also join our effort to lobby the government to change their position,” Ms Castle says.