New energy requirement 2015: a new building may use 3 litres oil/m2 (milestone). In 2005, average net heat consumption in existing buildings was 14 litres oil/m2. The Danish building code enumerates plans to legislate efficiency improvement in new, renovated and existing buildings in 2006, 2010 and 2015. The revised code also aims to introduce specific requirements in the Building Regulations relating to replacement of roofs, windows in a facade and oil and gas boilers, and to change of heat supply. Requirements for energy labelling or certification of buildings were adopted in June 2005 and have been in effect since 1 September 2006. Under the scheme buildings need an energy label, when they are newly constructed, when they are sold, and if they are rented out. For existing buildings certificates cannot be more than 5 years old. There are 14 classes covered by the labelling scheme, from A1 at the highest level to G2 at the lowest. New buildings must meet requirements corresponding to a B1 label. A Handbook has been developed for energy consultants establishing labels, in which two types of energy saving measures must be identified: immediately feasible ones and those feasible if carried out in addition to ongoing renovation. A scheme for the regular inspection of boilers and heating system was also implemented as of 1 September 2006, supplanting an already existing inspection scheme for oil-fired boilers. A scheme for air conditioning and large ventilation system inspection took effect from 1 January 2007.