Architects have said the Lib Dems’ ambitious policy to retrofit all homes to the Passivhaus EnerPHit standard is ‘unachievable’
With the Green Deal failing to address the UK’s retrofit challenge – just 746 households have installed energy efficiency measure in the scheme’s first year – the party wants to transform the government’s flagship scheme into ‘a comprehensive one-off programme to bring all homes up to the EnerPHit standard by 2050’.
Back in September, Liberal Democrat members voted in favour of the party’s green growth policy which suggested that if brought into power they would launch a retrofit programme to bring all the UK’s existing homes up to the Passivhaus standard.
But the profession has cast doubt over whether this is achievable with architects suggesting the policy is ‘short-sighted’ and could hold ‘unintended consequences’.
Fionn Stevenson, head of Sheffield School of Architecture, said: ‘This kind of commitment is only achievable with the political will to seriously invest in housing retrofit with government backed finance and loans. The tragedy about this short-sighted approach from government is that they are missing out on a ‘win-win’ situation - more jobs and energy saved.’
Energy efficiency expert and founder of the Usable Buildings Trust Bill Bordass added: ‘The Lib Dem’s EnerPHit commitment is not achievable for the whole stock. In my view, it is not sensible to apply uniform standards to all existing buildings - what is appropriate and practicable will depend on the context.
‘I also wonder why there is so much emphasis on domestic retrofit, when there’s so much that needs to be improved with new-build and with non-domestic.’
Concern was also raised about the lack of skills within the industry, which would be needed to make the retrofit commitment happen.
Architects do not have the skills to do this yet
Stevenson commented: ‘Architects do not have the skills to do this yet. Upstream we need to re-address how schools of architecture teach detailing. Many tutors are still not familiar with how to detail an airtight building. We need to capacity build our educators as well as architects solely in practice.’
Cullinan Studio’s Robin Nicholson added: ‘Architects ought to gain the skills if they want to remain employed. At 1,200 homes to be upgraded every day between now and 2050, there is a lot of work to be done and if architects don’t want to do it, others will happily oblige.’
But Jerry Tate, principal of Jerry Tate Architects remains optimistic: ‘This has the opportunity to make architects fantastically relevant to the future of building.
‘Frankly I think the basic consumer desire is there and legislation like this could kick-start a whole new chapter of building.’
Jerry Tate, principal, Jerry Tate Architects
‘The fabric of existing houses could almost certainly be upgraded at an elemental level to meet general EnerPHit standards, so long as you were to allow a few fundamental changes to the external appearance of buildings (which could be tricky in historic areas).
‘However to actually get the right result from the PHPP and gain certification for every existing building is definitely not possible, some are just going to be the wrong shape, face the wrong way or be too overshadowed.In our experience for example bungalows are tricky in the PHPP calculation as the ratio of external envelope to internal space is not good.
‘These are skills we probably all should have in terms of sustainable design and the ability to do our own energy calculations. This has the opportunity to make architects fantastically relevant to the future of building!
‘The appetite for retrofit comes down to legislation and energy prices. The problem with the Green Deal was the financing, as far as I can see lots of people have had an assessment and not many took the actual ‘Deal’. In a funny kind of way this could be positive, I cannot seem to find any figures about who then went on to do something separately; this might be hard to capture I suppose.
Legislation like this could kick-start a whole new chapter of building
‘Frankly the basic consumer desire is there and legislation like this could kick-start a whole new chapter of building.
‘A standard based on using the PHPP calculation is a great idea, but whether it should be a fixed level at EnerPHit certification, or whether there should be a more realistic sliding scale depending on the particular building is a question I think needs addressing in the policy proposal.
Fionn Stevenson, head of school, Sheffield School of Architecture
‘This kind of commitment is only achievable with the political will to seriously invest in housing retrofit with government backed finance and loans. Recent moves by the government to remove Green Tarriffs do not bode well in this regard. The tragedy about this short-sighted approach from government is that they are missing out on a ‘win-win’ situation - more jobs and energy saved.
‘Architects do not have the skills to do this yet. Upstream we need to re-address how schools of architecture teach detailing. Many tutors are still not familiar with how to detail an airtight building. We need to capacity build our educators as well as architects solely in practice.
‘A bigger question is - does the construction industry have the skills to do this? The answer at the moment is a firm no. Better standards of construction, codes of practice, skill training investment are all needed to ensure that EnerPHit does not backfire due to poor installation practices. We are already seeing the bitter fruits of poor MVHR system installation and commissioning, where residents just turn the whole thing off due to the excessive noise and draughts. We need to learn to run before we walk and that means getting the fabric right first.
The Green Deal was never going to work
‘The Green Deal was never going to work on the poor loan terms available and is a daft idea anyway, as it is based on a ‘pick and mix’ approach of individual measures, rather than a whole house system approach.
The better alternative would be something like EnerPHit, but without the MVHR systems and with a properly considered whole lifecycle approach in relation to resource use - I am not convinced yet that we want or need MVHR in a maritime climate.
We can achieve positive carbon retrofit if we pay attention to how we supply energy to our homes at a communal and district level, and turn our attention more to natural materials.
We also need our retrofit to be robust and resilient in the UK- mechanical systems are more vulnerable than windows, as they rely on power. We are likely to see increasing power cuts due to climate change and the gap between demand and supply in the UK, due to lack of renewable investment.
Robin Nicholson, Cullinan Studio
‘Whether this is achievable all depends on the money; at the moment there is neither money nor political leadership unfortunately.
Architects ought to gain the skills if they want to remain employed
‘Architects ought to gain the skills if they want to remain employed. At 1,200 homes to be upgraded every day between now and 2050, there is a lot of work to be done and if architects don’t want to do it, others will happily oblige.
Bill Bordass, Usable Buildings Trust
‘The application of uniform standards worries me, particularly for existing dwellings. It is important to take proper account of context - what you have got and how it is being used - or one may need up with severe unintended consequences, in particular for the health of the building fabric and the occupants.
‘I also wonder why there is so much emphasis on domestic retrofit, when there’s so much that needs to be improved with new build and with non-domestic!
The Lib Dem’s EnerPHit commitment is not achievable for the whole stock
‘The Lib Dem’s EnerPHit commitment is not achievable for the whole stock. It is horses for courses. In my view, it is not sensible to apply uniform standards to all existing buildings: what is appropriate and practicable will depend on the context. In some contexts, there may be risks of severe unintended consequences for example if moisture accumulates: this can affect the heath of the fabric and the occupants, sometimes catastrophically.
‘The EnerPHit standard was developed for a central European climate. Its preference is for external wall insulation, which may not be acceptable for some buildings of architectural and historic interest, or impossible for legal and boundary reasons. Its u-value standard is 0.15 W/m²K, but recent research into insulating traditional solid walls in the British climate suggests that values this low may take one into an area of increasing risks and diminishing returns.
‘Architects don’t have the skills yet. Unfortunately architectural education has focused mostly on the design of new buildings, not the performance of existing ones - including recently-completed ones. Experience and insights are lacking. Even the science and guidance commonly used leaves something to be desired.
‘Having said that, there is no reason why architects should not be able to develop appropriate skills and insights if they have the will to do so. However, this will need commitment and support, including educators, professional institutions and policymakers that are more knowledgeable about building performance in use.
‘We need a collective enterprise to improve the performance of the existing building stock in appropriate and responsible ways. It is horses for courses. What is the context? What are the opportunities and constraints? What are the risks and benefits? Is there the budget?
‘In my view the Green Deal went about things the wrong way round. It essentially started with the premise that the barriers were largely financial. In my view, they were much more about scientific understanding, technical competence, industry capacity both generally and locally, and client confidence. Saving energy and carbon also needs to be seen as a social enterprise, not just a technical one: committed individuals are much more likely to get good results. Policymakers are now beginning to realise some of these things, and the Green Deal may eventually be adapted accordingly. The cost and payback period of an EnerPHit project would also tend to be way outside the Golden Rule.
‘It is important to prioritise. It is not just where we get to by 2050 but how we get there, e.g. our total CO2 emissions over the period from now to then. Ideally we want the most improvement, all-round, at an affordable cost, in the short, the medium and the long term. Being a relatively expensive thing to do, EnerPHit may be a component in a long term strategy and appropriate in suitable circumstances where people have the money to spend and the risks can be minimised. Because of its cost, progress will be slow, and any work will best be done at an “opportunity point”, e.g. where the building is empty and in conjunction with other major work.
‘Meanwhile, there is often a lot that can be done in the short term to improve comfort and save energy and carbon without making major alterations to the building fabric.
‘Another complementary route would be a programme designed to appeal to people (e.g. some owner-occupiers with savings currently earning very little interest), who might be prepared to fund their own deep retrofits if they had more confidence in the solutions being offered. This could be used to help build capacity.’
Adrian Leaman, Usable Buildings Trust
‘I’m wary of ‘green growth’, it seems myopic, with a lot of ‘have your cake and eat it’, just as most of the green policies have been so far. So nothing new there.
‘[The commitment] is glib and technocratic. Why just domestic, for example? And why does it need to be so catch-all? If there is one thing that we have learned from thirty years of building performance studies, it is that context trumps everything. A second thing we have learned is that complexity of the enemy of good performance, and this looks like yet another way of achieving that.
We need a radical overhaul of architectural and professional education to achieve this
‘Do architects have the skills to do this? No. They are far too fixated with appearances and do not pay proper heed to performance. There needs to be a radical overhaul of architectural and professional education to achieve anything close.’
Chris Wilford, associate director, PRP
‘Both the EnerPHit and the Passivhaus standard provide a rigorous process of design and control through construction which has been demonstrated to successfully deliver in outturn performance something close to the designed performance. To this end, I think a commitment to the design process offered by the Passivhaus planning package is realistic, but there are some very real hurdles in expecting all existing homes to achieve the actual Enerphit standard.
‘Although EnerPHit, in recognition of the difficulties presented by retrofit, offers certain relaxations over Passivhaus, it still expects a target air tightness of 0.6 air changes per hour @ 50 pascals or at least a maximum airtightness of 1 air change per hour. This alone is very difficult to achieve without very invasive works inside the building. For example sealing floor void to wall junctions. For single, private family dwellings this is a labour of love, and most households will not get near this.
‘However, with larger apartment blocks the balance shifts due to the better ratio of floor area to external envelope, and the Passivhaus or EnerPHit target becomes more realistic.
‘To design with the Passivhaus planning package, architects need to understand the principles of building physics and low energy design. Not many architects are trained this way.’
‘Finding the incentives, financial or otherwise to encourage the take up of any retrofit is a different issue to the standard applied to that retrofit. Whatever the standard chosen, there are also stages towards achieving the whole house solution which can be sensibly mapped out and undertaken as financial viability allows.’
‘There is a big debate in the industry around the performance gap, and there doesn’t seem to be any standard which competes with Passivhaus (or EnerPHit) in closing this performance gap. So it is the methodology that is valuable. However, we know we can achieve good energy reductions without going as far as EnerPhit. So in many cases a bespoke, future proofed, upgrade strategy may be more appropriate and more viable, and the cost of going that extra not to achieve certification becomes disproportionate.’
Andrew Goodman, founder, Good Architecture
I don’t think the Lib Dem’s proposal is achievable, but I believe that space heating demand not exceeding 40 kWh/m²yr is achievable and should be become the statutory requirement (the AECB Silver Standard).
It will only work if there are some financial incentives, and not just 5 per cent VAT as per the AJ’s campaign.
The PHPP is based on sensible building physics. It is the best predictor of building performance and should be the accepted methodology for Building Regulations’ compliance.
The government does not understand the simplicity of the need to reduce energy use in buildings. It’s obsessed with counting carbon, with a compliance methodology designed and driven by political dogma that considers reducing energy consumption as an unacceptable regulatory burden. It allows all kinds of ‘offsets’ that result in unacceptably high levels of building energy consumption.
The rigour on site that comes from the Passivhaus/ EnerPHit certification process is also proven to result in buildings that perform as designed, which cannot be said of satisfying Building Regulations requirements at the moment.
Tom Dollard, head of sustainability, Pollard Thomas Edwards Architects
It is not financially viable to apply the EnerPHit standard to all existing homes
Whilst my experience of the EnerPHit standard on projects has been positive, I don’t believe it is financially or practically viable to apply this to all existing homes.
EnerPHit is a premium retrofit standard that should be incentivised for existing homes, but it will not suit all existing homes and clients.
We have already seen many architects, helped by engineers/Passivhaus consultants, deal skilfully with EnerPHit projects. Some architects have the skills and knowledge already to deal with this challenge, but the majority of the profession are not there yet and will need to rely on early M/E advice and Passivhaus consultancy.
This option will make more of difference than the green deal if it is suitably incentivised. EnerPHit is the best option (short of full Passivhaus), but it may not be realistic.
Profession casts doubt on Lib Dem's proposed retrofit policy