Simon Childs was sentenced to a minimum of 32 years in prison before he can be considered for parole at Maidstone Crown Court on Friday May 24.
He used petrol to start a fire which engulfed the home in Spitfire Road, resulting in the death of 65-year-old Jacqueline Allen.
Childs, 52, broke into the property at around 9pm on November 17 last year. He took fuel containers from a shed and started a fire in a lean-to next to the kitchen.
Emergency services attended and found Mrs Allen inside but she was pronounced dead after being taken to hospital.
‘Local residents bravely tried to rescue the occupants from the house, but the fire was just too intense’
Another person, who cannot be identified, was found in the garden having jumped to safety from a first-floor bedroom and suffered injuries including a fractured toe.
Officers located Childs soon afterwards at a nearby address in Hurricane Close and arrested him.
He was already subject to a number of conditions prohibiting him from visiting the house in Spitfire Road.
These restrictions had been imposed by a court following a previous conviction for assault against a former partner.
An investigation by the Kent and Essex Serious Crime Directorate uncovered evidence that on the day of the fire, Childs had threatened to set alight a caravan belonging to a man he suspected of having a relationship with the former partner.
He was heard threatening to ‘burn the house down’ and was responsible for dozens of abusive messages and phone calls demanding to know where she was.
It was proved that he was missing from the address in Hurricane Close between 8.54pm and 9.04pm when the fire was started.
Under interviews Childs denied any blame, and claimed he had gone to sit in his van to smoke cannabis.
At Maidstone Crown Court he pleaded not guilty to charges of murder and attempted murder; he was convicted on both counts on May 22.
Detective Chief Inspector Patrick Milford said: “Simon Child’s actions were deliberate and calculated.
“He broke into the property knowing that Jacqueline Allen and another person were inside, before starting a devastating fire which spread rapidly with tragic consequences.
“Local residents bravely tried to rescue the occupants from the house, but the fire was just too intense.”
‘Jackie would have given her last breath for us and she did that night. Our whole world was taken from under us’
He added: “The sentence imposed is unlikely to lessen the grief caused by this senseless loss of life, but it will at least hopefully provide reassurances that Childs is now unable to cause further harm, and will be spending many years in prison.”
Neighbours and friends set up online fundraising pages to help pay for funeral costs and help the family after all their belongings were destroyed in the fire. A dog also died in the blaze.
Mrs Allen’s family issued a statement saying: ”There are no words to express the sadness and loss of our beloved mother and grandmother.
“Jackie would have given her last breath for us and she did that night. Our whole world was taken from under us.
“We are trying to rebuild our lives together as a family and now need time to grieve.”