We've long known that being green is good for the environment - now it seems buying green could be good for our wallets. A growing school of thought argues that choosing properties for their energy efficiency is the best way to 'future-proof' a real estate investment portfolio. The gospel according to green is everywhere. Brighton House Associates, a United States alternative investor research firm, sums up the sentiment. 'Lower operating costs, higher occupancy rates, and greater property values are but a few of the many benefits of green or environmentally conscious real estate. What may have started as a socially-charged movement has attracted some of the largest real estate investors and property managers, and they have begun reaping the rewards.' It seems demand is there. A global survey by Jones Lang LaSalle and CoreNet Global confirms that more than 40 per cent of corporate real estate executives would pay up to 10 per cent more to rent a sustainable building, despite the economic downturn. As for residential construction, Anwar Harland-Khan, CEO of Sustain Worldwide - a membership organisation of global developers and professionals whose mission is to raise awareness, share knowledge and catalyse business growth in sustainable development, architecture, design and living - believes green is the future. 'Undoubtedly, eco-homes are the future of residential property worldwide. It stands to reason because the sustainable homes being built today are stylish, beautifully finished, warm and light spaces. Not only are they attractive, they are cheaper to run because they require less heating and cooling than a conventional house, they are better insulated and fitted out with 'hands-off' energy saving applications. What's more they will appreciate in value faster because eco-homes are more 'future proofed' than a traditionally built existing house.' Charlie Williams, business development manager of Terresens, an eco-friendly leaseback property developer in France, agrees. 'Thinking green has gone beyond small-scale recycling and taking fewer long-haul flights. Housing is one of the main contributors to CO2 emissions and we have a moral and legal responsibility to consider sustainable eco-friendly alternatives for the properties we own. With increasing levels of European Union environmental legislation being passed, potential property buyers need to start planning now to ensure that their investments meet the criteria in years to come in order to avoid incurring heavy operating and possibly redevelopment costs later down the line. 'For those considering purchasing a leaseback property, where the value of the property is calculated on the income which the property is capable of producing, developments that lack high eco-ratings and sustainability features [and therefore have higher operating costs as a result] will start to trail behind with regards to rental growth and lead to adverse yield movements.' Soon, it may be mandatory. Examples of green legislation increasingly being passed worldwide include Britain's Building a Greener Future, which proposes that all new homes be constructed to a zero carbon standard by 2016. In addition, Britain and other member states, including France, are committed to the Europe 2020 strategy which requires 20 per cent of all energy needs to be sourced from renewables. To enable investors to make an informed choice about property investment in France, each Terresens development holds an ecological rating out of 150. Present projects include a luxurious apartment building, La Chapelle, in the traditional alpine village of Sainte Foy, where use of natural building materials, water retrieval and sustainable management push the rating to 112. The completed Les Mazets de Ventoux residences in Malaucene, built using only natural products and eco-friendly building principles such as bio-paint, renewable electricity and treatment of green areas, scored a rating of 89. Developers are similarly eco-savvy in Estonia, identified by KPMG research as a country focusing heavily on eco-developments. Estonia invests much of its European funding in projects with an environmental appeal. As a result, its production of electricity from renewable sources increased nearly threefold in 2009. The government's approval of the Estonian Renewable Energy Action Plan last year, preparing for the share of renewable energy to grow to at least 25 per cent of all domestic consumption by 2020, has triggered further eco-friendly efforts. Property Secrets has the perfect property for investors seeking a sustainable development in Estonia. Fully planned and carbon negative, Keble House is a two-bedroom, natural wood terrace house and is set within the residential complex, Oxford Park, the only new community development in Europe to plan its own independent renewable heat and electricity source - allowing it an A+ rating. Located 30 minutes' drive from the capital Tallinn, Keble House is priced at Euro107,307 (HK$1.2 million), with 20 per cent covered by the developer. 'With a five-year rental guarantee at 5 per cent of purchase price, this is the perfect opportunity to reap the rewards from Estonia's emerging market by investing in a beautiful and sustainable eco-friendly property,' says Alan Forsyth, director of Property Secrets.