The vast majority of residential buildings put up in the early 1970s are badly insulated and drain energy through heat loss, much like water drains uninhibited from a sink with a broken plug. Undertaking insulation work to deal with such ‘thermal sieves’ would come at considerable cost to building owners. True, the cost can be recovered over the long term through the resulting energy savings, but many owners are reluctant to carry out the work, especially when oil prices (and thus perceived energy prices) are low. They consider taking on debt for an uncertain future financial gain not a safe bet.
But there is one solution – adding one or two floors to existing apartment buildings, selling those extra apartments and funding the insulation work with the proceeds from the sale. This fits with the ‘passive building’ concept under which the thermal characteristics of a building are tuned such that the influence of external factors is diminished and that maintaining conditions inside the building requires minimal resources.
The work would include:
- Installing a laminated timber frame around the building to help support the additional construction
- Filling in the gaps between the frame beams with hempcrete (a bio-composite of hemp and lime) insulation, a low-price material that combines energy efficiency and low CO2 emissions in its manufacture
- Enlarging south-facing French windows and creating a buffer zone on the northern side
- Installing a central wood-burning heater or linking up with an existing district heating system
- Bringing LED lightbulbs into broader use
- Fitting photovoltaic panels onto the façade
- Installing mini-windmills on the roof
- Covering the roof with soil, an excellent thermal insulant, with the option of turning it into a vegetable and fruit garden equipped with a composter to recycle organic waste.
All this turns poorly insulated buildings into passive buildings that produce more energy than they consume. The technical means exist for meeting the extraordinary challenge of global warming at the level of modern housing. It’s up to government authorities to facilitate such operations through suitable tax incentives and regulatory measures, among other things by modifying ground plans and authorising additional floors in apartment buildings, except in cases where that would cause clear harm.
BNP Paribas Investment Partners’ environmental fund managers keep close track of all these developments, which are, all at once, technical, financial and political in nature. They assess their practical aspects to determine which companies will be best able to benefit from these new growth opportunities.