Carer Matthew White was supposedly gardening for an elderly family friend.
But when he relapsed into drugs he took the opportunity to pilfer £700 from the 78-year-old woman's home.
White, 40, of Walnut Buildings in Radstock, admitted a burglary which, due to his previous break-ins, qualified him for a minimum three years in prison.
But a judge at Bristol Crown Court concluded the minimum term would be unjust and jailed him for a year.
The Recorder of Bristol His Honour Judge Peter Blair QC told him: "If you can repay this woman in due course obviously that's an important thing to aim at.
"This was a mean-spirited and concerning burglary."
Kenneth Bell, prosecuting, said the victim noticed items had been knocked from her window sill and blamed it on the cat.
She later discovered £700 was missing from a drawer at her home in Springfield Crescent, Radstock.
Mr Bell said the OAP was a light sleeper and felt she would have been woken by an intruder, though she may not have been disturbed as she is hard of hearing.
Emily Heggadon, defending, said her client worked as a carer for his mum, who was not well.
She told the court: "He had a profound drug problem with crack cocaine and heroin.
"Months in prison have got him clean."
Miss Heggadon said it was a very unsophisticated burglary with little planning and asked for remorseful White to have a last chance and a rehabilitation order.
She said: "He would wish for the opportunity to repay her."
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