You can lock your doors against burglars, but making sure you don't fall victim to a scam – even in the safety of your own home – is much less straightforward.

More than 22,000 people were scammed in 2012, according to Citizens Advice, and fraudsters are constantly inventing ways to swindle you out of your cash. The month of May has been designated Scams Awareness Month by Citizens Advice and Trading Standards, and forewarned is forearmed so here are 27 to look out for.

Door-to-door scams

1. Fake Green Deal sales You answer your door to be told you are entitled to £10,000 of funding for Green Deal home improvements, such as insulation or a new boiler. You are then asked to pay an administration fee.

2. Unnecessary damp proofing You are offered a free damp proofing survey. The surveyor always finds damp which needs urgent attention, quotes a high price and requests an immediate deposit.

3. Home maintenance services A trader offers you a cheap quote to pave your patio or driveway, carry out home maintenance or gardening services, or repair "unsafe" roof tiles. They demand an upfront cash payment to start or finish the job – then scarper with the money or make unreasonable charges for botched work.

4. Food sales Someone offers to sell you (inedible) fresh or frozen fish very cheaply, but only if you are prepared to pay £100s for several boxes, sight unseen.

5. Fake energy-saving gadgets You are offered a plug-in gadget at a "sale price" of £99, which the seller claims will cut your electricity use by 40%.

'Too good to be true' scams

6. Fake dates You join a dating website and are contacted by an extremely good looking potential date who lives abroad. After starting an online romance the scammer asks for money for emergency bills.

7. Council tax refunds You are told by a cold-caller that you are owed a rebate on your council tax bill or are overpaying because your property is in the wrong tax band. You are then asked to hand over your bank or credit card details so your money can be refunded.

8. Council tax discount You are told that if you start paying by direct debit you will get a discount – but first you need to pay an administration fee.

9. Dodgy job website You register your CV at a job site and quickly get a call or email from an employment agency guaranteeing you a job, but only if you first pay a fee.

10. Bogus pay cheque You are called or sent an email from someone who wants to give you a job, and offered a cheque in advance of your first payday. Cash the cheque and you'll be told you've been overpaid and must return the money via an online transfer – before the cheque bounces.

11. Training course claim You see an advert online for a high salaried job, but are asked to pay for a training course first.

12. Prize scam You are called, texted or emailed and congratulated for winning a prize or even a huge lottery pot (although you can't remember buying a ticket). In order to collect your winnings you are asked to pay a processing fee or to call a premium rate phone line.

13. Bad investments You are cold-called and offered a once-in-a-lifetime opportunity to invest your life savings, for example in carbon credits, plots of land, fine wine or exclusive stocks and shares, which are certain to make you rich. Needless to say they are not.

14. Loan arrangers You are called or texted by a fraudster and invited to apply for a "guaranteed loan". After you've given your personal information, including your bank details, you are told to pay an application fee.

15. Pension problems You receive an "urgent" phone call from "The Pensions Helpline" or your pension provider stating that you are entitled to a £1,000 pension bonus from the government, or that your pension has been underpaid. In order to receive your money you must pay a fee or give out your personal details on a premium rate line.

16. PPI refunds You are texted or called by someone claiming to be your bank, the Ministry of Justice, or a PPI company and told you are owed money in the form of mis-sold PPI payments – but you must pay an administration fee before the refund can be processed.

17. Tax back You receive an email from HMRC offering you a huge tax refund if you give your personal details online or by email.

18. Unhealthy sales You see an online advert for a free trial of slimming tablets or skin products. However, you unwittingly sign up for regular monthly payments which cannot be cancelled.

19. Noise rebatement You are called by someone claiming to be from the government and told you may be entitled to compensation because a place where you once worked has been condemned as too noisy on health grounds. You are asked to pay a fee to find out more.

Scams which prey on your fears

20. Missed payments You are sent a fake council tax bill or told you are in arrears, and asked to pay immediately over the phone.

21. Telephone debt You are called by "Her Majesty's Court" and told you have defaulted on a debt for an expensive telephone preference service. You are asked for immediate payment over the phone and warned you will be disconnected and face arrest or a court summons if you refuse to pay. If you hang up, the fraudster will stay on the line so you'll think your line has been disconnected.

22. Truant's fee The "Education Welfare Service" calls to tell you that your child failed to attend school that day and asks you for a £340 penalty over the phone.

23. Courier scams You are called on your landline by your bank and told that fraudsters have used your debit or credit card and it needs to be replaced. You call your bank, which confirms this. You are told to key in your pin number and hand over your card to a courier who will arrive soon. However, between receiving the call and dialling your bank you didn't hear a dial tone and are actually still speaking to the scammers, who never disconnected the line.

24. Holiday help You are sent an email from a friend or relative whose account has been hacked. You are told they are stranded abroad and need you to send them money urgently. They are not, and do not require any money.

25. Virus hoax You are called by "Microsoft Windows Support" and told your PC has a virus or is running slowly. The problem can be solved remotely if you give them your credit card details and/or remote access to your PC.

26. Medical emergency You are called and told your grandchild has been in a road accident abroad. Cries for help are screamed down the phone while the caller says you need to send money immediately to cover medical costs.

27. Rogue traders A police officer calls claiming criminals are trying to steal money from your bank account, and that a special "safe account" has been set up for you to transfer your savings into. You are told that clerks at your bank are under surveillance and that revealing why you are transferring the money will jeopardise covert police work.

Reporting scams

If you encounter any of the above scams you should report them to the following organisations:

1. Action Fraud (0300 123 2040)

2. Your local Trading Standards Office via Citizens Advice (08454 04 05 06)

3. Your local police station, using non-emergency number 101.