Energy effciency in housing needs to address...a wider range of issues...to solve a broader range of problems such as fuel poverty and bottlenecks due to under-capacity in the National Grid.
― Homes are responsible for 28% of greenhouse gas emissions and when commercial buildings are included that rises to 40%. Tackling the thermal efficiency of buildings is not only about climate change, but it is one of the most important single issues for addressing climate change.
― While it is technically possible to get to a position where no buildings emit greenhouse gases in operation, this report focusses on getting buildings to a point where it is no longer financial viable to go further. Installing renewable energy will then be used to ‘sweep up’ the remaining emissions. This is known as a ‘fabric first’ approach.
― There are many benefits to a fabric first approach – it is generally cheaper to do, produces better outcomes for the householder and directly saves them money.
― Should a fabric first approach be ‘realistic’ (simpler, cheaper and closer to existing standards) or ‘aspirational’ (more complex, holistic and costly)? There are many substantial benefits to an ‘aspirational’ approach, including overall cost. While the upfront cost of retrofit can look high, the all-system lifetime costs of renewable solutions instead is almost certainly much higher. The investment in the electricity grid alone to cope with a massive surge in demand if we move to renewable electricity will be enormous.
― Every house is different so there cannot be a single target for how ‘aspirational’ to be. But the goal should be a reduction of between 60% and 90% of energy usage through insulation for the entire housing stock, with a 75% average. This means an aim of reducing energy consumption from an average of 17 MWh per household now to an average of 5 MWh.
― This is made more difficult because of the ‘performance gap’. This is the difference between what official Scottish public policy says has been achieved in home energy efficiency and what has actually been measured to be the case. Modelling is greatly over-estimating the impact of current actions. The current SAP model used is not fit for purpose and poor quality work can simply render predictions meaningless.
― As well as operational energy (what it takes to run a house) there is embedded energy (the energy it took to create its materials and build it).
― But it isn’t only about energy – building moisture is bad for human health and the single biggest cause of damage to fabric over time. Retrofit can increase moisture problems by reducing drafts which act as ventilation, so this must be properly managed. Likewise some retrofit materials themselves can give off pollutants which are bad for health so should be avoided.
― About 25% of homes were built before 1919 and have a different set of issues. These must be treated differently because if they are treated in the same way as more modern buildings it can actually cause their performance to deteriorate.
― All of the above requires change – better surveying, returning to much greater use of natural building materials, refocussing on the ongoing importance of proper maintenance, greatly reducing resource use and waste in the construction industry and more.
― The focus on energy efficiency should not detract from the ongoing failure on basic fabric maintenance – Glasgow alone has a £6 billion backlog, largely because of poor maintenance by private landlords. Often these basic repairs are required before energy performance is tackled where for example a leaking roof must be addressed before insulation is fitted.
― All of this faces a barrier: a severe lack of qualified designers and contractors.
― The costs of ‘deep retrofit’ used in this report are high, but these cannot be reduced until we start acting at scale to gain proper efficiencies.
― The report then proposes 19 solutions to these problems, including levelling VAT on new-build and retrofit, subject retrofit projects to proper building control scrutiny and site inspections for quality control, require PAS 2035 standard for retrofit, require plans to demonstrate clearly and in detail how heat loss is to be prevented, use post-completion performance tests, make indoor air quality a key aspect of design, overhaul the SAP system, better training for designers and fitters, investment in much better bespoke surveying and put in place an assumption against demolition.
― The report then describes the practices that will be needed to achieve the above – loft insulation, floor insulation, replacing windows and doors, triple glazing, draughtproofing (this covers 40 per cent of heat loss) and heating replacement. The value of wall insulation is sometimes overstated but may be appropriate as well.
― Both economically and environmentally it is important to source the maximum amount of the materials required for this work from Scotland.
― To retrofit 100,000 a year will require a workforce of 25,000 people. These jobs would involve about ten per cent at managerial and senior technical level, about 40 per cent at skilled trades level (particularly joiners, plumbers and electricians) and the remaining half semi-skilled (trained on installation of insulation and draught-proofing).
― This will cost about £25,000 per building – but only if we do this at scale and therefore gain the efficiency benefits of doing that. The total cost in Scotland will be in the order of £60bn to £65bn.
― This only twice as much as current notional Scottish Government estimates but those do not bring buildings up to the necessary standard. To put this in perspective the sum needed is only two thirds of Scotland’s contribution to the UK defence budget for the period of time needed to complete this work.