Regulations that came into force on 1st October 2015 require both smoke alarms and carbon monoxide alarms to be installed in rented accommodation. 

The carbon monoxide alarms are only required where any room in premises is wholly or party used as living accommodation and contains a solid fuel burning appliance. 

The issue to watch out for is that the Regulations provide that the landlord is to check the alarms are in working order on the day that the tenants are entitled to possession of the property. Arguably, therefore, someone needs to attend the property on the first day that the tenants enter into possession so as to check that the alarms work at that time and for them to record (e.g. the tenant signing the inventory) they are in working order.