Annette Coe carbon monoxide death: Man found guilty of two charges
Annette Coe, 71, collapsed at her home in St Edmunds Road, Ipswich, in 2012 and died in hospital.
Peter Sykes, 68, of Castle Road, Hadleigh, had denied four charges at Norwich Crown Court.
He was found guilty of two health and safety offences. A verdict on a charge of manslaughter and one other offence is yet to be given.
Ms Coe died on 6 December 2012 from carbon monoxide poisoning.
The jury is due to return on Wednesday to continue considering its verdicts on the charge of manslaughter by gross negligence and the remaining health and safety charge following a three-week trial.