The energy efficient retrofit of our leaky and inefficient homes and buildings needs to play a vital part in any post-COVID green recovery. The UK’s housing stock accounted for nearly a fifth of the UK’s total carbon dioxide emissions last year. 
3,200 excess deaths a year are linked directly to cold, damp homes and there is a £1.4-2 billion annual cost to the NHS of treating health conditions made worse by poor housing. 
Having a national programme to making our homes and buildings more energy efficient would help address the threats of climate breakdown and fuel poverty as well as generating a significant number of well-paid and skilled new jobs and would help kick-start a low carbon economy after the COVID-19 crisis.
As the Government Advisers the Committee on Climate Change (CCC) said: “Making homes energy efficient and climate resilient is one of the UK’s biggest opportunities.“ Pedro Guertler from energy think tank E3G said: “There is no other infrastructure project that can do more for the UK’s clean and resilient economic recovery ..it can quickly boost local jobs in areas of greatest need, stimulate demand by saving households hundreds of pounds whilst improving health and slashing carbon emissions.“
The £2 billion earmarked for the Government’s forthcoming Green Homes Grants scheme is a good start but not anywhere near the £45 billion annual investment on combating climate change that the CCC has recommended. There needs to be investment in a national retrofit programme as part of our green recovery of the economy after COVID-19.
The need for joined-up thinking
It is also important for policy-makers to consider that getting energy efficient retrofits right is not a simple box-ticking exercise of adding individual insulation measures. It helps to think of homes and buildings as complex systems with all the constituent parts adding to the whole performance.
Taking a ‘whole house’ approach involves consideration of all 4 key principles of energy efficient refurbishment.
Insulation: For walls, floors, roofs, lofts and windows, energy efficiency obviously depends on good levels of insulation.
Airtightness: Airtightness (or reduction of draughts) is an important aspect of energy efficiency which can make a huge impact on the warmth and comfort of a home.
Continuity of insulation (or minimising ‘thermal bridging’): To work best, insulation needs to work in a continuous ‘blanket’ around the house, minimising any gaps in the insulation (known as ‘thermal bridges’). Examples of ‘thermal bridges’ include through stones through cavity walls or gaps in insulation where the wall meets the roof, which breaks the continuity of insulation and loses heat out of the building.
The importance of reducing ‘thermal bridges’ increases as the level of insulation increases.
Ventilation: As airtightness improves in a building, it is also vital that suitable approaches to ventilation are considered carefully, so that there is no impact on occupant health or building structure.
It is obviously also important not to forget remedial and repair works before undertaking energy efficiency work to avoid trapped moisture and degradation of the building fabric.
Retrofit needs to be undertaken in a systematic ‘whole house’ approach, with a good understanding of the building physics behind the work and taking into account the 4 key principles of energy efficiency and any effects on the building fabric. If this is ignored or neglected then potentially serious ‘unintended consequences’ can be the result.
Mould growth and poor indoor air quality can result from applying insulation and airtightness measures without appropriate ventilation, and can lead to serious health issues for occupants.
Damage to the building fabric, particularly rotting timber, can result from not understanding the effect of insulation on the building fabric.
Reduced insulation performance and building fabric damage can result from interstitial condensation where airtightness and the principles of moisture movement are not understood.
The good news is that new 2019 Retrofit Standards PAS 2030 and 2035 are beginning to be adopted within Government policies, albeit slowly. These standards recognise the complexity of retrofit and specify professional levels of competency required to undertake retrofit work together with adopting the ‘whole house’ approach.
Green Homes Grants
The Government’s £2 billion Green Homes Grant scheme has been a welcome first step on the UK’s journey to a green recovery after COVID-19. We would cautiously encourage people to apply for the Grants, while making sure that a ‘whole house’ approach is undertaken which considers all 4 key principles of energy efficient refurbishment, to minimise ‘unintended consequences’ or problems.
Chayley Collis, Communications Manager, Green Building Store www.greenbuildingstore.co.uk