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Approaches To NetZero Housing And Common Failings?

Community Housing, Seend, Wiltshire

May, 2024 |

The complexities in interpretation and opportunities for obfuscation around NetZero mean that the housing industry is already embedded in confusion around delivery and flooded with greenwash claims. There is no doubt there are several essential elements for NetZero that are frequently omitted from new housing projects. The reasons for these omissions range from lack of knowledge to conscious decisions to prioritise ease by one or other party and short-term gains.

The three essential ingredients for NetZero are:

1. Highly energy efficient using ALL the Passivhaus criteria: This includes high levels of airtightness that enables effective use of whole house ventilation with heat recovery.
This ensures –

a. low energy demand so that a revitalised national grid could be viable in a future NetZero economy.

b. low bills for householders, especially important for social housing.

c. significant health benefits that will pay huge dividends in relation to untenable pressures on our National Health Service.

2. Use of bio-based materials: The UK Climate Change Committee advised in 2019 that all new housing should be built in timber, wherever feasible. This requires upskilling in the use of timber and using this resource sparingly (sequestered carbon claims can simply disguise unnecessary profligate use). Using bio-based materials beyond the frame itself, considering the insulations specified, their embodied carbon cost, and their potential to be recycled. Understanding the behaviour of insulations (and rigid boards) in relation to moisture and vapour permeability.

3. Simplified heating and hot water solutions: Prioritising investment towards longevity (fabric) rather than high embodied carbon and expensive technology. Technology will need replacement over much shorter time periods and require regular maintenance. The technology route is a convenient fix, especially for developers who leave the complexity of managing those systems behind them, but it is not a great outcome for housing associations or councils. The more complex the system, the higher the risk that design and commissioning are not executed well, and the system underperforms in practice. Hundreds of thousands of heat pumps will be installed over the next decade, how large might your maintenance and replacement budget need to be if you oversee large numbers of houses? Can you be sure the controls will be used/managed optimally by occupiers? Additional investment in higher quality housing requires a keen focus to achieving the full Passivhaus criteria (this MUST include triple-glazing, very good airtightness, and whole house heat recovery ventilation).

If we follow these three key approaches to NetZero, we can ensure there are multiple co-benefits to individuals, to the organisations that own these houses, and to the wider society we live in. Greenwash solutions to NetZero will not deliver highly valuable outcomes and unfortunately remain embedded in business-as-usual attitudes, especially maximising profit for the few. NetZero should be part of an integrated shift to better economic approaches that takes account of all the value gains and long term capital consequences, well beyond short term financial profit – this full accounting is what makes a truly sustainable future possible.

On the 20th of June a ten-house scheme in Seend, Wiltshire has an Open Day that showcases this approach. If you want to attend, then the details for this event are on this link: https://www.passivhaustrust.org.uk/event_detail.php?eId=1321

 

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Passivhaus Trust Member
Anti-greenwash Charter - a structured framework to ensure transparent and honest environmental communications.
Buildoffsite Property Assurance Scheme (BOPAS) was developed to address the concerns and perceived risks associated with innovative construction. BOPAS is recognised by the principal mortgage lenders as providing the necessary assurance underpinned by a warranty provision, that the property will be readily mortgageable for at least 60 years.
certified passivhaus consultant
Buildoffsite Property Assurance Scheme (BOPAS) was developed to address these concerns and perceived risks associated with innovative construction. BOPAS is recognised by the principal mortgage lenders as providing the necessary assurance underpinned by a warranty provision, that the property will be readily mortgageable for at least 60 years.