Renovating your kitchen or bathroom is an opportunity to save on energy costs, writes Sarah Pickette.

When it comes to renovating, kitchens and bathrooms are often at the top of homeowners' to-do lists. So if you are tackling one or both of these rooms, it pays to improve your energy efficiency while you're at it.

According to EnergyAustralia, the kitchen accounts for about 16 per cent of the average home's energy usage. The refrigerator alone is responsible for seven per cent of household energy consumption. Given that the fridge draws so much power, it is worth investing in an energy-saving model: a 20-year-old three-star 400L fridge costs about $282 a year to run; a new three-star 400L fridge costs about $114 a year.

"Dishwashers are another appliance where upgrading to an energy-efficient model can make a difference," says Nick Fry, Retravision's General Manager of Whitegoods and Appliances. "An energy-efficient dishwasher that has the highest Water Efficiency Labelling and Standards (WELS) rating could save a family around $50 a year in utility costs."

In the bathroom, hot water can account for up to 37 per cent of your household power consumption. EnergyAustralia estimates a small electric storage hot-water system that's not set to offpeak can add a whopping $670 to your annual power bill. In comparison, a solar hot-water system (with gas boost) will only use about $105 worth of energy over a year.

"Installing showerheads and tapware with high WELS ratings will also make a difference to your power bill, simply because the less water you use in the bathroom, the less power you need to heat it," says Darryn Parkinson, Design and Construction Director of Your Abode, a Sydney building-design firm that specialises in eco-friendly renovations.

Another way to stay on top of your power consumption is to take the opportunity during renovation to ensure your bathroom is well ventilated and has adequate natural light; this will minimise your use of the exhaust fan and artificial lighting. Consider, too, whether or not you really need a heated towel rails or a spa bath. According to electricity distributor CitiPower, daily use of both would add an extra $100 per quarter to your power bill.