In the past two weeks the nation has seen the temperature significantly drop. This can only mean one thing, winter is on its way.

In a bid to stay warm many of us will be cranking up the heating in our homes.

However, you can avoid being slapped with a high energy bill over the Christmas period, thanks to some helpful advice from Martin Lewis.

In a series of true or false questions, the MoneySavingExpert guru revealed his tips and tricks, as reported in a column in the Sunday Mirror .

Martin Lewis reveals his tips on how you can save money on heating in the colder months

And you might be surprised at some of the answers, as Martin reveals some suppliers offer discounts if you pay your energy bill as a monthly direct debit.

Read on to find out more.

True or false: When you change energy supplier someone will need to visit your home?

False. Nobody usually visits your home. Your pipes don’t change and your gas and electricity won’t get cut off. You don’t even need to contact your old energy supplier to tell it you’re switching. The only thing that changes is the price and service. It’s so easy to switch. It isn’t a big deal.

True or false: It’s cheaper to leave the heating on low all day rather than have it turned off and on?

False(ish). Just pay to pump energy in as and when is needed, as to keep pumping it in constantly isn’t efficient. Using a timer’s best, because your thermostat is designed to turn your heating on and off to keep your home at the temperature you set it. This is the view of both the Energy Saving Trust and British Gas, so in general I’d stick with that.

Yet some heating engineers argue that keeping all the radiators on full but with the boiler down can reduce condensation. Whereas on and off can make it worse. As condensation helps conduct heat outside the home – you lose heat more quickly and will use more energy as a result. So if your house is prone to condensation, you may want to think about it.

True or false: Renters can’t switch energy provider without their landlord's permission?

False. You have a right to switch energy provider in your home even if you only pay the rent. There are two exceptions to this 1) If you don’t pay for energy yourself, it’s all included in your rent 2) If you’re looking to switch meter, eg from pre-payment to a credit meter, as that’s a physical change to the property that needs permission.

So feel free to do a comparison. Just plug your details into my cheapenergyclub.com or any other ofgem.co.uk - approved comparison site and it’ll tell you the best deal for you. Just make sure you select ‘all tariffs’ as some comparison sites now default to only show you the ones that will pay them (my cheap energy club doesn’t do this).

If the landlord says it’s written into your contract that you can’t switch, challenge it. Preventing a tenant from changing energy suppliers may be viewed as an unfair term in a tenancy agreement. Talk to Citizens Advice to see if it can help.

True or false: If you’re in credit when you switch energy provider they must give you the money back?

True (now anyway). If you pay by direct debit and when you leave an energy firm you’re in credit, then since 2014 you should automatically get this back. But track it and if the supplier doesn’t, call it and ask for the cash.

If you switched before 2014 and think you might have been in credit then call to check as they operated a ‘don’t ask don’t get policy’ and you can still ask. Like Aston, who emailed: “Eight minutes work calling my old energy suppliers, got £140 refunded after leaving in credit. Why don’t more people do this?”

True or false: The cheapest way to pay energy bills is by direct debit?

True (but specifically it needs to be monthly direct debit). Then suppliers offer discounts of around 7%. Yet while you pay less in total, as its estimating your usage, if it overestimates it could ask you for more cash – leaving you in-credit - or worse, leaving you underpaying, and in debt with it. So ensure you always give regular meter readings to get accurate bills. And if you think its estimate is wrong, you’ve a right to challenge.

True or false: I must get boiler cover with my energy provider?

False. Many energy firms use our fear of losing heating to charge hefty insurance costs. They also want us to think there’s some link between our energy provider and our boiler cover. There isn’t - you’re not locked in, so if you do need it, go elsewhere, like Amanda who emailed: “I swapped my boiler cover company and saved £213 a year whilst also increasing cover - and still with an annual service included. Thanks.”

You can choose between boiler-only or central heating cover and to find the cheapest cover use a comparison site such as uswitch.com , energyhelpline.com and moneysupermarket.com . If it’s right for you, get cover ASAP, before the true cold weather kicks in, as almost all new policies have a no-claims period within the first 14-30 days.