Cold? Close the curtains

Over the telephone, a week after the defence of his PhD thesis, Dr. Ed Melet (57) easily lists up the usual measures that make up the standard package for energy-renovation: insulation all around, triple-glazed windows, roof covered with solar cells, heating and cooling by heat pump in combination with heat and cold storage in the ground, and ventilation through heat-exchangers. That is how to make old houses energy-neutral. Except that, in practice, it often doesn’t work out that way. It’s known as the rebound effect: the gains from new technologies that increase the efficiency of resource use turn out to be lower than expected, because of behavioural or other systemic responses. Often, the control over the installation is not intuitive enough, and its response time is typically on the order of hours.“People want an immediate effect, so they drive to the DIY store to buy an air conditioner”, Melet explains.

People found the use of the activating facade intuitive and effective

Inspired by the self-evident behaviour of people choosing the right clothing after one look outside, Melet decided to give users control over the insulation of a room by adding one or more layers of an activating, flexible, and adaptive facade (AfaF). In the test pavilion, built at the Amsterdam University of Applied Sciences HvA, there were four layers to choose from: a windproof and waterproof layer, two insulation layers of 2 and 4 cm thick, and an insulating sun shield.

Half of the 180 people who participated in the test were given control over the indoor climate by including the layers, an electric heater, a lamp and a blanket. People found the use of the activating facade intuitive and effective. Having control gave them a sense of ownership of the indoor climate and hence a greater tolerance of heat and cold. Melet quotes the Ikea-effect: even if the result is not perfect, you still appreciate it because you have put an effort into it.

The experimental pavilion, with a large opening in the facade that people had to close by covering it only with layers of fabric, is far from the standard building practice. Besides, the use of natural fibres would result in required thickness layers of 14 cm, which is not really practical either.

Melet invited six architecture studios for a workshop on activating facades. He wanted to see whether architects could implement the concept of an activating, flexible, and adaptive facade (AfaF) in their design, and what forms would result.

Activating Facade design by Aris Gkitzias, OMA with closed glass and insulating layers

The most evident difference in their designs from the test pavilion was that most of them choose to position the layers behind glass, which neatly keeps out air and water. Aris Gkitzias’ design (from OMA), for example, features a glass facade that can be folded open when weather allows.

Activating facades resulted in up to 25 % energy reduction

Melet is well aware that his ideas are far from current renovation practice. But he argues that aerogel-filled curtains could well replace styrofoam insulation layers. Some advantages of his activating facades are lower costs, smaller material footprint, and, most importantly, initiating environmentally friendly behaviour leading perhaps to climate-awareness. Tests showed that people who had control over their facade, po​​stponed switching on the heater. According to simulations, activating facades resulted in up to 25% energy reduction.

He adds: “In times of climate change and material scarcity, we keep developing technology that enables us to continue our way of living unchanged. I think it’s time to start on the other side and change people’s behaviour and awareness by giving them more control over their indoor climate.”

• Ed Melet, Activerende gevels. Naar gedrag beïnvloedende gebouwen, PhD supervisors Professor Emeritus Mick Eekhout and Professor Arjan van Timmeren (Faculty of Architecture and Built Environment – BK): 13 December 2017.