37 Building construction; installation of apparatus for lighting, heating, steam generating, cooking, refrigerating, drying, air-conditioning, ventilating, heat recovery, air filtering and water supply, of sanitary installations, air filters as well as parts and accessories of the aforesaid apparatus and installations; repair of apparatus for lighting, heating, steam generating, cooking, refrigerating, drying, air-conditioning, ventilating, heat recovery, air filtering and water supply, of sanitary installations, air filters as well as parts and accessories of the aforesaid apparatus and installations; maintenance of apparatus for lighting, heating, steam generating, cooking, refrigerating, drying, air-conditioning, ventilating, heat recovery, air filtering and water supply, of sanitary installations, air filters as well as parts and accessories of the aforesaid apparatus and installations; construction consultancy