The cost analysis for construction of Qatar’s first Passivhaus (‘passive house’ in English) shows that significantly improved environmental performance may only require a relatively modest increase in capital costs for buildings.
Officially unveiled on 22 April, the villa was constructed as part of an experimental project called Baytna,a joint initiative by Qatar Green Building Council (QGBC), Kahramaa and Barwa Real Estate Groupto study the benefits of the Passivhaus design in Qatar’s hot and arid climate.
‘One of the main outputs of the Baytna project is to derive the most cost effective and practicable means of achieving more sustainable housing in Qatar and the region.’ said Dr Alex Amato, Head of Sustainability at QGBC.
The project’s aim was to keep the inevitable uplift in capital costs required to comply with Passivhaus building standards to within 15 to 20 percent above those of a conventional villa. In less than eight months of construction, the Passivhaus villa achieved this target. With just a 16 percent increase in capital costs, it is predicted to consume 50 percent less water and energy, and reduce carbon dioxide emissions by half.
The main causes for uplift in construction costs were increased thickness of insulation, triple glazing of window and door systems, high-efficiency lighting and advanced light control systems, as well as sun shading devices in the atrium.
These measures also led to cost saving from the reduction in size of the air-conditioning mechanical equipment required, due to the reduced cooling loads, which are roughly one third that of the conventional villa.
Dr Amato believes that there is potential to further reduce the capital costs of adopting Passivhaus standards for Qatar’s climate if ‘lean construction’ techniques are applied, such as prefabrication and off-site manufacturing, together with sustainable procurement supply chain opportunities.