Cornwall Fire and Rescue Service has seen more than a five-fold increase in carbon monoxide (CO) poisoning cases over the last 12 months, it said.
Carbon monoxide was confirmed in 49 of Cornwall's properties in 2012, compared to nine the previous year.
Of those incidents, 25 people needed emergency treatment.
Mark Pratten, safety officer for the service, said the economic downturn was partly to blame as people could not afford to get appliances serviced.
Since the death of a family at their home in Camborne last month, and a St Ives landlady in January, Cornwall Fire and Rescue Service said its helpline had received more than 80 calls a day.
One hardware chain across Devon and Cornwall confirmed all stores had sold out of carbon monoxide alarms.
Mr Pratten said he believed the economic downturn had also impacted on people not being able to afford to get boilers serviced, chimneys swept or wood burner flues checked on a regular basis.
Carbon monoxide is a colourless, odourless gas produced by the burning of fuels, including gas, oil, wood and coal. Inhaling it reduces the blood's ability to carry oxygen and can be fatal.
Mr Pratten said he would like to see all new properties in the UK fitted with carbon monoxide detectors as standard.
About 50 people die each year in the UK in their homes from carbon monoxide poisoning.