Stan and Irene Bishton are urging people to have their boilers checked
Ten people were treated for carbon monoxide poisoning after the deadly fumes filled a house in Wirral.
The cause was a blocked flue from an unserviced gas central heating boiler at Stan and Irene Bishton's home.
The couple were saved by Mrs Bishton's sister, who called in and found Mrs Bishton collapsed on the floor.
Mr Bishton was in bed but had become overcome by the fumes. Mrs Bishton's sister, her husband and six ambulance crew were also treated in hospital.
Mr and Mrs Bishton are now backing a Health Protection Agency (HPA) campaign to remind people to have their boilers serviced regularly.
Mr Bishton said: "I hadn't had the boiler serviced for two years and it didn't occur to me that there might have been a problem with it.
"You don't think about these things until something happens.
"Now we're having the entire system replaced and we've bought audible CO alarms."
Dr Richard Jarvis, from the HPA's Cheshire and Merseyside Health Protection Unit, said: "Carbon monoxide is an invisible potential killer that can lurk in any home if domestic boilers and heating appliances are not properly installed by qualified and registered engineers and serviced at least once a year."