If passive house is Everest, we’ve left base camp

This article was originally published in issue 48 of Passive House Plus magazine. Want immediate access to all back issues and exclusive extra content? Click here to subscribe for as little as €15, or click here to receive the next issue free of charge

At present, many players in the construction industry are quietly investigating the passive house standard. With approximately 3,000 passive units in the pipeline in Ireland, on site or heading for site and in tandem with Cairn Homes’ recent announcement that they are adopting the standard and will add over 1,700 units, this has become a mega trend. So why the move to passive?

The rise of green finance and lower interest rates linked to Environmental, Social and Governance (ESG) has been a major driver.

This source of finance is especially important to the construction industry given the investment required to make projects happen. If you cannot prove through reporting that you are delivering on your ESG outcomes, not being able to access lower interest finance puts you at a competitive disadvantage.

The raft of legislation from Europe is another key driver. The Corporate Sustainability Reporting Directive (CSRD) comes into play in Ireland this year for twenty-six companies.

A further 2,000 companies must report next year, including many in construction, and this information will be data mapped, allowing the finance and investment industry to easily compare one company to another.

The recast Energy Performance of Buildings Directive was enacted in Europe in May, calling for zero emission buildings. Over the next couple of years government will be deciding what this looks like in Ireland.

Consider the E in ESG. We need to reduce both the embodied and operational carbon of the built environment. We need to look at how we design and build, the systems we use, and to engage with the entire supply chain – it is the collective effort from all that will deliver a lower embodied carbon result. This is no easy task and there is an industry view emerging that it will take some time, and that operational carbon interventions may more quickly deliver reductions.

Operational carbon is the in-use carbon produced from the finished building. A target to reduce is easier to achieve because it is the output of the design and build activity. What happens on site following appropriate design, reduces the performance gap and therefore operational carbon.

Why does passive house solve these problems?

In the 1980s, Professor Wolfgang Feist wanted to prove that it was possible to build without a traditional heating system even in colder climates.

The first building, built 33 years ago, is still being monitored and has been an intensive research project from day one. Feist set up the Passive House Institute, a not-for-profit independent research institute, and currently it offers the only internationally recognised, performance-based energy standard in construction. There are now nineteen affiliates globally, including the Passive House Association of Ireland, and as of June 2024, 43,800 units have been certified. To say that this standard is tried and tested is an understatement.

It has proven effective through post occupancy evaluation and the institute continue to review, learn and always improve the standard. A science-based approach, the standard also speaks to the G in ESG. It reduces operational carbon compared to NZEB with no green washing. Outcomes are explicit because the performance targets are absolute, with metrics defined through a transparent evidence-based process. The passive house planning package (PHPP) is a robust, accurate and practical tool that supports compliance and design, and produces energy forecasts with an elevated level of accuracy. The performance gap is now in the margin of error.

Our industry is on a progressive journey to zero and how we have done things to now has served us well. As Stephen O’Shea from Cairn Homes recently said, we already use the ingredients, it is just the recipe for passive is slightly different. To be bold, we have the solution for zero energy building. If passive house is the summit of Everest, then NZEB is a base camp on that journey.

But what will it cost?

We already use the ingredients, it is just that the recipe for passive is slightly different.

A study in the UK by Atkins in 2019 found that passive projects in the UK cost approximately an extra 4 per cent but reduce to nominal levels if adopted at scale. The reality is every time we want to do something different it costs money. Whether you build ZEB buildings today or in 3 years, you will incur the cost of doing so. The beauty of passive is that once you nail the process the cost difference is marginal.

There are so many more benefits, for homeowners, councils and housing bodies – passive house protects the value of your assets. Maintenance costs are lower, the building fabric is protected, and the need to retrofit new buildings to meet 2050 targets will be obviated.

The social advantages speak to the S in ESG. Passive buildings offer greater comfort, healthier buildings, improving the quality of life for the occupants. And because the performance gap is closed, the monetary savings are real. What would you do with the money you normally spend on heating if you had it in your pocket today?

Everything has its time

Consider Steve Jobs of Apple. In the 1980s he said that he wanted everybody on the planet to carry a computer in their pocket. In the apocryphal words of Henry Ford, who revolutionised the production of motor cars, “If I had asked people what they wanted, they would have said faster horses.” In the 1980s Wolfgang Feist designed a building without heating. So, as you get in your car and look at the little computer in your pocket, ask yourself – is now the time for passive house?