Energy Mythbusting

If you have a gas, oil or LPG (liquefied petroleum gas) central heating system, it will always be cheaper to set the system timer so the hot water comes on only when required.

However, if you use an electrical immersion heater and have an Economy 7 or 10 tariff (where energy is cheaper at night), it's cheaper to heat your water during the night. Make sure your tank is well insulated to prevent it cooling during the day, though.

For more on this, our Economy 7: Is It Right For You? guide sets out to crack whether those with it should stick, and if those without it should switch. It also includes nine tips to max it, eg, beware when the clocks move – Economy 7 timers can be set incorrectly.

If you're unsure what tariff you're on, check your latest energy bill or ask your energy firm.

No – at least not on their own. Smart meters simply replace your existing gas and electricity meters (one for each), measure your usage and automatically send meter readings to your supplier each month. However, Citizens Advice say they can help you identify ways to save energy via the in-home display that comes with your smart meter.

This is a small gadget that communicates wirelessly with your smart meters, monitoring what energy you're using and showing you how much it costs, in near real time.

With more information on your day-to-day energy use, the idea is that it will help you spot ways to cut back. For more, see our Smart Meters guide. 

There is no one answer for this. It's highly dependent on the heating system you use, and the usage in other areas of the house.

This depends on what you're after. Halogen heaters are directional. Once on, you instantly feel the heat. As soon as you turn them off, the heat quickly dissipates. Convection heaters, electric panel heaters or free-standing electric radiators work by heating the air around them to create a convection current. They take some time to heat a room, but once turned off the heat lingers.

Usually, it's best to use your central heating to heat your home rather than relying on electric heaters, especially if you have gas central heating. If you're only using a couple of rooms, you can use thermostatic radiator valves so that your central heating isn't heating empty rooms. Electricity is much more expensive than gas, so using electric heaters can ramp up your energy bills.

The Energy Saving Trust says whether a combi or a standard boiler is cheaper to run will depend on your lifestyle and how much hot water you use.

With a standard boiler, water is heated by your boiler and stored in a hot water tank for when you need it. With a combi boiler, you don't have a hot water tank and instead water is heated up instantly when you turn on the hot tap.

If your household doesn't use too much water, combi boilers can be more efficient, as they don't leave water sitting in a tank where it can lose heat. However, combi boilers tend to be less efficient at heating water in the first place, so if you're a large household using lots of water it might be cheaper to have a standard boiler with a well-insulated tank.

The main thing which will affect how expensive your boiler is to run is its efficiency. Having an A-rated condensing boiler (standard or combi) will be cheaper to run than an older non-condensing boiler.