Switching provider in the energy price war can cut your annual fuel bill by hundreds of pounds. But that effort should be only the start if a chunk of the heat you are paying for is going out of the window. A number of websites can teach you how to save big money with a small investment.

A good starting point is the Energy Saving Trust website at energysavingtrust.org.uk. It offers advice from quick tips to a detailed assessment of your home. Tamara Mauro, of the trust, says that the average household can save £300 a year and add £10,000 to a property’s value. She says: “These are easy ways to save money and protect the environment.”

Painless changes it suggests include turning down your thermostat by one degree to save up to 10 per cent on central heating, turning off appliances – not to standby – to save close to £40 a year and using energysaving light bulbs to save £100 in each bulb’s lifetime.

Key steps among its top ten measures demand a bigger outlay. These include double-glazing and loft and cavity wall insulation. Cavity wall insulation fits most homes built since the 1920s, costs about £260 and pays for itself within two years. Free guidance on all the measures is available on e-mail – via the website – or by calling 0800 512012.

The site’s home energy check, meanwhile, is a ten-minute survey that generates an instant estimate of the annual savings you could enjoy and tells you how to achieve them. Those with larger or more antiquated homes can save much more than the £300 average.

Grants for many of the measures are available through local authorities and energy suppliers. The website’s grant-search facility tells you which, if any, you can claim. Most are available regardless of means.

Other substantial awards exist for renewable energy technologies, such as solar panels and wind turbines. A grant search for solar water heating in my London postcode revealed that funding is available from the Government’s Low Carbon Buildings Programme and my local council. Calls to both confirmed that I could be eligible for combined funding of up to £3,500 of the estimated £4,000 cost.

To qualify for government help – available direct at lowcarbonbuildings.org.uk – I would first need to install loft insulation and energysaving light bulbs. But act fast because half the £6.8 million earmarked for homeowners has already been allocated.

Many of these technologies are not yet cost-effective. Unless you can secure significant grant aid, they could take decades to pay for themselves. In the meantime, Ms Mauro urges people to get the basics right – closing curtains to retain heat is a good start.

CASE STUDY: It's worth checking

Bernadette Griffin, of Birmingham, has been interested in energy efficiency for five or six years and says that saving money and helping the environment are twin motivations. The marketing executive, 29, used the Energy Saving Trust (EST) home energy check to see how the flat she shares with her husband, Paul, measures up.

She says: “Our home is very modern, so almost everything was right, but we now save an extra £20 a year with energy-saving light bulbs and a boiler upgrade.”

Mrs Griffin has recommended the site to family and friends and plans to use the energy check again if she and her husband move house. She also keeps close track of energy rates at comparison websites and shops for appliances with the EST’s energy-efficiency stickers.