Carbon Monoxide Poisoning: Threat and the Importance of Boiler Servicing and Maintenance Most incidents involving carbon monoxide poisoning involves heating appliances which is expected given the prevalence of central heating installations in Great Britain due to their larger heat input and significant hours of operations. For the period July 01, 2011 to June 30, 2012, there is an estimated 51.7 million (22 million households) with gas central heating boilers. For more info, please go to Elite Gas Services.