37 Building construction; repair, maintenance and installation services; services for the maintenance, repair, unblocking, cleaning, clearing, descaling, sterilising, disinfecting, fumigating and deodorising of drainage and piping systems, sewers, manholes, grating, culverts, chambers, gullies, flues and channels for the passage of liquids, solids or of gases; roofing, carpentry and electrician services; installation, repair and maintenance of electricity supply apparatus and of fixtures thereof and of electrical and electronic apparatus and instruments; repair, installation and maintenance of electrical systems for residential and commercial wiring, electrical apparatus and appliances, electrical panels, electrical outlets, fuse boards, switches and light fixtures; installation, maintenance, servicing and repair of computer hardware, household devices, home electrical systems and surveillance and security systems in homes; installation, maintenance, servicing and repair of kitchen and other household appliances; installation, maintenance, servicing and repair of apparatus for heating and lighting; installation, servicing, maintenance and repair of central heating systems; installation, maintenance and repair of apparatus and systems for monitoring the performance of heating systems; installation, servicing, maintenance and repair of heating and lighting control apparatus; installation, refurbishment, inspection, repair, maintenance and decommissioning of energy supply installations and energy production plants; installation, servicing, repair and maintenance of electrical appliances or instruments using electricity; installation, servicing, repair and maintenance of electricity meters, air conditioning and ventilation appliances; installation, maintenance, servicing and repair of solar heating and power installations; installation, maintenance, servicing and repair of batteries and energy storage apparatus; installation of equipment and facilities for the collection, storage, distribution, processing of electricity and renewable energy; information, advisory and consultancy services relating to all the aforesaid services