UK Government home energy efficiency

Two new studies show the UK government has been failing on home energy efficiency since 2012, and developers of speculative office buildings manipulate design modelling to achieve their desired results. They also show what can be done about it.

Progress has stalled

In the UK progress on tackling climate change has stalled. Emissions from buildings have risen by four per cent since 2014. According to the Climate Change Commission (CCC), “effective new strategies and policies are urgently needed to ensure that emissions continue to fall in line with the commitments agreed by Parliament”.

A projection of greenhouse gas emissions from buildings along the current path, and the required path, showing the extent of the British government’s policy gap. Source: UK Climate Change Commission

But the government’s Clean Growth Strategy, published in 2017, contains no concrete proposals for improving energy efficiency.

There is an aspiration to upgrade as many homes as possible to Energy Performance Certificate Grade C by 2035, provided it is “practical, cost effective and affordable”. But there is no definition of “cost effective and affordable” nor recognition of the broader social benefits of energy efficiency investments. This lets the industry off the hook.

Nineteen million homes (70 per cent) are currently below the Grade C standard. Fuel poverty is widespread. But the annual rate of insulation installed in existing British homes has fallen off a cliff.

The annual rate of insulation installed in existing British homes fell dramatically after 2012 and has not recovered because of a policy vacuum, despite several consultations

2016 figures for insulation against what should be happening (source: CCC):

Type2016 indicator levelActual level
Loft insulations545,00064,000
Cavity wall insulations200,00092,000
Solid wall insulations90,00031,000

Since most boilers have now been replaced with efficient condensing models (around 70 per cent in 2016), the focus needs to be on insulation. According to the CCC, the UK needs to insulate all lofts that are practicable by 2022, all cavity walls by 2030, and two million solid walls by 2030, to reduce overall emissions from the sector by 20 per cent.

Possibilities in the residential sector

What to do? One new study shows that energy use in all existing homes can be cost effectively cut by one quarter (or one half if allowance is made for falling technology costs) by 2035, but only if savings from the external benefits – greenhouse gas emission reduction and health and safety – are factored in to the cost benefit calculation.

This would not be done by the market alone, and therefore would need some form of subsidy or support, say the researchers from the Regulatory Assistance Project (RAP). Its uses the CCC’s central scenario – which meets the legally binding British carbon budgets.

The proportions of different energy saving methods in homes in the CCC’s three potential future scenarios:
  • Limited ambition scenario includes all energy efficiency measures whose energy cost savings exceed the associated capital costs
  • Cost-effective scenario includes all energy efficiency measures that are estimated to be cost-effective according to criteria used by the U.K. government to appraise public policies and projects, energy cost savings plus monetary value of comfort and air quality improvements, and carbon emissions reductions
  • Current technical potential scenario includes all measures currently available and applicable to today’s housing stock.

The analysis shows that between 66,000 and 86,000 new jobs could be sustained annually by this level of retrofit activity at a total cost of around £85.2 billion at today’s prices, which would deliver benefits of £92.7 billion.

Of the benefits, energy cost savings account for 54 per cent of the total cost, greenhouse gas savings for 37 per cent, and total air quality and comfort improvements for just under 10 per cent.

Policy support is required to encourage the building sector to make the necessary investments since investors would not recoup their investment from energy savings alone.

RAP’s research shows what policy it should address. It also shows the barriers – the fragmented supply chain, a focus on single rather than multiple or complementary measures with no guarantees on performance, and significant hassle for the household.

But there is a further problem. Because of cutbacks in local government spending, councils are not able to enforce minimum energy efficiency standards in the rented sector, which is over 20 per cent of the residential housing sector. Budgets for this work have been cut by one fifth over the last five years and more resources need to be allocated for this purpose to tackle fuel poverty and meet climate goals.

What about non-residential buildings?

Residential buildings account for over 75 per cent of emissions from all buildings.

One quarter of emissions from existing buildings are from non-residential buildings. A significant number of non-residential new builds are speculative building, where developers construct office blocks in the hope that someone will rent them.

These new buildings are often designed by computer modelling to achieve certain standards. The standards can be regulatory ones, such as the building regulations (specifically Part L which deals with energy), and voluntary ones such as BREEAM (the Building Research Establishment’s Environmental Assessment Methodology).

When researchers interviewed designers of these speculative office buildings they found that the software is manipulated during the design process to make it look as if the building would achieve a given energy-saving level without any actual in-use evidence to support this.

Furthermore, the use of software obscures any subsequent objective checking of how the results were achieved.

The energy savings claimed as a result of using this software are used by developers to promote their buildings to buyers or tenants. Because there is an incentive to exaggerate, this is factored into certain decisions that are made when using this software, the researchers found.

For example, several interviewees described this as ‘fiddling the models’, and the types of choices made are revealed in the following quotes:

“Comparing Tas and IES (two types of software packages: Tas Engineering and Integrated Environmental Solutions) you could get a 20% difference depending … on how you refine the … defaults”, said one consultant.

“A BREEAM Excellent rating requires an EPC of 47 … The M&E consultant said ‘Help! I can only get to an EPC of 54’. What we did to achieve the EPC was move from a level three model to a level five model,” said another architect.

“In practice, once a standard, for example BREEAM ‘Excellent’, has been reached, nobody ever asks the question of how it was achieved”, said a letting agent. The same applies to the process of securing a satisfactory Energy Performance Certificate.

The researchers note that “such strategic decisions in digital design are ‘black boxed’ away from view”. Besides, the eventual occupants are unknown and therefore their energy use patterns are unknown. The projections are built on guesswork.

Moreover, the data on the heat emitted by office equipment used to calculate the required mechanical ventilation and heat recovery is often out of date, since modern office technology gives off far less heat than it did just a few years ago. This could result in excess energy use being designed into the heating and cooling system to compensate.

Tenants and purchasers of such buildings should be aware of this, take the predictions with a pinch of salt and ask penetrating questions.

David Thorpe’s two latest books are Passive Solar Architecture Pocket Reference and Solar Energy Pocket Reference. He’s also the author of Energy Management in Building and Sustainable Home Refurbishment.

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  1. The figures are from another report, so maybe not one for you to answer, but I’m confused by the “Current technical potential scenario” for “Fabric”.

    Surely if we consider Passivhaus or just generally high performance fabric-first renovation, potential for improvements in space heating efficiency are enormous, removing any need for boiler, heat pumps or (gawd help us) heat networks.

  2. Something wrong with the images in this article. See all the image tags showing, eg “[insert total-buildings.gif. Caption: Residential buildings account for over 75 per cent of emissions from all buildings.”