“Over the long term, fabric first is the most economical approach to sustainable building”. At first sight, this is a non-controversial statement but look a little closer and some interesting issues appear. Here, Neil Smith, Head of Research and Innovation at the National House-Building Council (NHBC), offers her interpretation of this statement.
There is no doubt that improving the fabric performance of buildings offers the best and most sustainable, long-term approach to delivering energy efficiency. New construction provides the one-off opportunity to create a fabric that will continue to deliver benefits over decades, even centuries, to come. Providing excellent levels of insulation to floors, walls and roofs from day one, and paying attention to air tightness means that these aspects will not need to be re-visited for the life of the building.
Keeping a close eye on the developing Government policy and as a key supporter and sponsor of the Zero Carbon Hub, NHBC has been involved with many exemplar homes. The first ones were brimming with technology, and some included them all: heat pumps, mechanical ventilation with heat recovery (MVHR), solar thermal panels for hot water and solar photovoltaic panels for electricity. Even for technophiles, the array of equipment could be daunting enough, but how bewildering would it be for home occupants with no knowledge or experience or interest?
In order to get the most from their homes, people living in them need to realise which technologies they’ve got, engage with them, read the instructions and operate them properly. For some, operating a single piece of technology properly may be doable, although evidence does suggest that people struggle to operate even relatively simple and familiar technology such as central heating controls.
But operating multiple systems that interact could be a challenge, even for the geeks amongst us. And then there’s the maintenance: I understand that a substantial proportion of homeowners disregard manufacturers’ recommendations that gas central heating systems should be serviced annually. This may be for reasons of lack of knowledge or (false) economy. But how then do we rate the likelihood of the additional kit installed in the zero carbon home being given any attention? And what are the safety consequences that could follow from neglecting roof-mounted solar panels containing very high temperature liquid?
Ask the same questions in relation to an energy-efficient building that has been designed around its very well insulated, airtight building fabric. There is no need for people living there to engage with the fabric: they don’t need to read about it, understand it or operate it. Nor are there additional maintenance requirements – no annual service; no filters. That sounds like a long list of advantages to me.
For the avoidance of doubt, I am not suggesting for a moment that buildings should not integrate new technologies. But I am clear that technologies should be used only in buildings where close attention has already been paid to the specification and construction of the fabric and that they should be chosen carefully, taking full account of occupants’ ability to use them properly and their willingness to ensure that they are maintained so that they are safe and efficient.