Real estate company Willbrook Management International will build a 40 million euro housing complex in Varna, said the company's executive director Daiana Voicu.Willbrook Diamond Residences will comprise 11 home buildings, recreation and entertainment facilities and a spa centre. It is expected to be finished by the end of 2009.The complex would be designed, built and used in line with strict environmental standards and would be Bulgaria's first green project, Voicu said. It will use energy-saving light and air conditioning sources. Water-saving aerators will be mounted in the bathrooms to save water. Local green producers will be picked to supply the construction materials.A survey by consultancy firm Colliers International showed eco-construction was just two per cent more expensive than conventional methods. Investors pay an average of $40 more per sq m while their direct financial benefits may exceed initial costs ten times.Willbrook Management International has earmarked a total of 250 million euro to develop other projects in the Bulgarian capital, Voicu said, without identifying particular locations.