Trading Standards are warning householders following a spate of complaints where some people have been cold called and persuaded to have their radiators cleaned out at costs ranging from £1300 to £1500.
In one case the householder already had an existing service contract and it was highly unlikely that this additional work would have been necessary.
Trading standards are advising people to exercise caution and ask themselves:
• Do their radiators really need cleaning out?
• Is the price being asked reasonable?
Advice from Trading Standards is not to do business with cold callers.
A spokesperson said: "If you think you need work done on your property seek quotes from reputable businesses.
"If you are not sure who to use look for recommendations and get help from friends or family, always have the full business details including name and address. If the trader is doing specialist work on central heating systems or electrics make sure they are qualified and competent.
"Please look out for anyone you know who could be vulnerable, friends, family or neighbours."
For advice or to report an incident call Citizens Advice Consumer Service 0808 223 1133 (1144 for Welsh)