Article 4
1. Member States may not prohibit, restrict or impede the placing on the market or entry into service within their territories of appliances and boilers which satisfy the requirements of this Directive, save as otherwise laid down in the Treaty or other Directives or Community provisions. 2. Member States shall take all necessary measures to ensure that boilers cannot be put into service unless they satisfy the efficiency requirements set out in Article 5 (1) and the conditions for entry into service which the Member States lay down on the basis of local climatic conditions and the energy and occupancy characteristics of the buildings. 3. However, Member States where back-boilers and/or boilers that are to be installed in the living space, are widely installed at the date of the adoption of the present Directive, shall continue to authorize their entry into service, provided that their efficiency both at rated output and at 30 % part load is not more than 4 % below the requirements laid down in Article 5 (1) for standard boilers. 4. The effects of the provisions in paragraphs 2 and 3 shall be constantly monitored by the Commission and analysed in the report to be submitted under Article 10. To this end the Member States shall forward to the Commission any information it requires to submit to the Council the proposed amendments, provided for in that Article, designed to ensure at all events the energy efficiency and free movement of boilers in the Community.