The conniving men had quoted a price for repairs to her home on Springfield Road in Linlithgow but the two men disappeared without any of the work being carried.
The crooks also targetted another house nearby and quoted £300 for garage repairs.
But the legitimate workmen were carrying out repairs to the property and declined the offer.
The suspects are described as being white, 5ft 8ins tall, in their late 30s, of heavy build with short shaved fair hair.
They spoke with Scottish west coast accents and were driving a white-coloured open back pick-up truck.
A police spokesperson said: “This has been a terrible experience for the woman and it has left her considerably out of pocket.
“We will not tolerate this kind of crime, and are appealing for anyone who may have been in the area at the time, and who may recognise the description of the men involved, to get in touch.
“Our advice to anyone else who is for people never to take on any cold callers, and only use trusted tradesmen who you have asked to come to your property and carry out any work.
“Anyone with any concerns about bogus workmen operating in their area should contact police.”
Anyone with any information is asked to contact Lothian and Borders Police on 0131 311 3131, or the charity Crimestoppers, in confidence and complete anonymity, on 0800 555 111.