Driving low-energy building performance

Driving low-energy building performance

If we were to look back in 20 years, what would we think of the current wave of policy-led district heating system implementations?

Have we learned from the wave of biomass solutions rolled out over the last 10 years (many of which are now mothballed), that were once favoured over energy efficiency measures?

We can’t fault the good intentions of legislation designed to improve energy efficiency in land and property developments. With the Building Regulations tackling progressive issues around energy efficiency and since the Merton Ruling, local authority policies have also been taking increasing strides further, sparking technically questionable commitments to energy generation in the urban environment.

However, the practical consequences are less apparent. Putting traditionally robust district heating systems into highly energy-efficient buildings leads to overheating, comfort issues and even health risks from unduly warming domestic water systems.

Ultimately, we then increasingly see the counter-intuitive, reactive engineering measures of retro fitting energy wasting ventilation into air tight buildings to combat these problems. If the homes we are to design for tomorrow need little more than a hairdryer to heat them, why pump lots of heat through our streets to meet an ever-diminishing heat demand to principally facilitate local efficient electricity generation from CHP? To add to that, we have to invest up to 10 per cent of the development costs into heat infrastructure.

District heating and CHP or trigeneration does make sense where density, demands and synergies exist in the development mix. However, in imminent new residential developments, it is becoming increasingly difficult to justify this approach from a carbon efficient or practical engineering perspective.

A more practical, engineering-led approach to low-energy building design will be founded on passive design principles, taking a ‘fabric first’ approach. Where the building fabric and design is able to take great strides towards achieving energy efficiency, policy should perhaps be informed and flexible – not prescriptive.

Never in the history of the built environment has the recent level of heightened and dynamic change and influence been experienced. Challenges will be faced and lessons learnt. We are still in the midst of this period of change and adaptation; during this period, we must listen to building engineers and physicists to guide development through. Ticking policy boxes and designing by crude compliance will lead to unfortunate legacies.

Looking forward, we will see the logic of engineering and knowledge beginning to challenge the definitions set in legislation. More pragmatic solutions – even the simplicity of the definitive “on/off” switch that electricity provides – will take hold as we look to apply technology to improve the energy performance of buildings still further.

The economic potential of challenging assumptions ingrained in current policy is already under investigation, and the impact of the findings could be far reaching. In 2023, we’ll quite likely wonder what took us so long.

Stuart McDougall

Stuart McDougall

Partner – Buildings

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