Passive House – a luxurious way to take climate action

 

At RISE Design Studio, we work hard to minimise the environmental impact and energy consumption of our projects. One way we do this is by working with the Passive House and EnerPHit standards. In October 2021, publisher and editor of Passive House Plus magazine, Jeff Colley, gave a TEdx talk in Tralee on ‘How Passive Houses can improve your life and help the planet’. Jeff’s talk highlighted some of the key reasons why the Passive House is key to tackling the climate emergency.

Passive House RISE Design Stdio

What is a Passive House?

A Passive House (or Passivhaus) tends to use energy sources from within the building, such as body heat, heat from the sun or light bulbs, or heat from indoor appliances to create a comfortable, healthy living environment. Typically, a Passive House features high levels of insulation to roofs, external walls, ground floors (with no heat loss at junctions), triple glazing and air tightness. A ventilation system recovers heat from stale outbound air and passes it onto incoming fresh air that is then filtered when entering the house.

Your home is your sanctuary

In an increasingly uncertain world, we are often made to feel that taking climate action equates with making sacrifices in our lives. However, the Passive House shows us how climate action does not need to feel like this. Instead, it can improve life in several ways. Most importantly, a Passive House costs very little to heat (and in some cases nothing at all), and the internal environment always feel fresh and comfortable, whatever the weather.

The emphasis on ‘future proofing’ means that a Passive House can withstand any weather and/or temperatures that the future may bring. As Jeff Colley explains in his talk, people who live in Passive Houses regularly describe constant comfort, no ‘cursing at the cold’ in the mornings, and peace and quiet – acoustic performance is very high, making it hard to hear anything outside or between party walls in flats/other shared accommodation.

No need for heating

Impressively, there are many examples of Passive Houses whose residents rarely or never turn on the heating system. In some houses, a heating system is not even needed, with only small battery-powered back-up if required. For example, of 18 sheltered housing units built in Devon for elderly people, the heating had not been turned on in nine of the units five years after construction. Similar accounts relate to Passive Houses in which there has been a boiler issue but this is not an urgent problem, as in more standard homes.

A healthy home is a happy home

In the west, we spend about 90% of our time in our buildings, making it important that our home is a healthy place to be. Experiences during the pandemic have also made us think more about air quality and ventilation. Recent research in Ireland suggests that the benefits of Passive Houses go even further than reducing energy use and creating a comfortable living environment. Over 200,000 global lung cancer deaths each year are estimated to be caused by the presence of radon in buildings. This is a particular issue when the weather is cold outside and the indoor environment is warm – radon can rise up from the ground into the living environment. The average levels of radon in a Passive House have been found to be much lower than in an average home.

Drawbacks?

Some critics have questioned whether the Passive House standard restricts architectural freedom. However, the standard is remarkably flexible and accommodates good design, in both retrofit and new build projects. The standard can be applied to any building, including commercial and residential, and even listed period buildings.

The first Passive House hospital is nearing completion in Frankfurt and Passive House schools are becoming increasingly common, such as the Harris Academy in Sutton. Impressively, the standard has also been used in a very progressive council housing scheme in Norwich. The standard can be used to create a good indoor environment for ‘things’ rather than people as well. For example, an Imperial War Museum archive near Cambridge uses the approach to protect its artefacts for future generations.

Jeff Colley suggested that the main drawback of living in a Passive House is that it may become hard to stay in other people’s homes when one has become so accustomed to such high comfort levels. Joking aside, the Passive House is an excellent example of how ‘being green’ doesn’t have to mean sacrifice. As Jeff argues, it is one form of radical climate action that everybody can agree to. We fully support this argument and we continue to work with clients on new build and retrofit projects that apply the Passive House and/or EnerPHit standard.

Photo: Hervé Abbadie and Karawitz

Passivhaus explained

 

Increasing the energy efficiency of buildings is a key concern for a sustainable architect. In this blog post, we look at the basic principles of the Passivhaus (or Passive House) standard: a sustainable construction concept that is the fastest growing energy performance standard in the world. Developed in the early 1990s in Germany, the standard can be applied to any type of building – residential, commercial, public and industrial – in any part of the world. 30,000 buildings now have the standard worldwide, with more and more non-residential buildings such as administrative buildings and schools being built to Passivhaus standards. Passivhaus standard components are also being applied to retrofit projects.

Passive house

So, what exactly is a passive house?

Not to be confused with solar architecture, although it shares some common principles, the key concern for an architect designing a passive house is to reduce dramatically the need for space heating/cooling and primary energy consumption, while at the same time creating good, healthy indoor air quality.

A well-designed and constructed passive house can allow for energy savings of up to 90% when compared to typical building stock in Europe, and over 75% when compared with the average new build designed for low energy consumption. This means that passive house owners and tenants tend not to worry about rising energy prices – passive houses require less than 15 kWh/(m2/yr) for heating and cooling, compared to an average of 150 kWh/(m2/yr) for the space heating demands of a typical house built since 2000.

A passive house uses energy sources from within the building, such as body heat, heat from the sun or light bulbs, or heat from indoor appliances to create a comfortable, healthy living environment. A mechanical heat recovery ventilation system allows fresh air to enter the building without letting heat out, and allows heat contained in exhaust air to be reused. This highly efficient heat recovery system means that fresh air is supplied without draughts and guarantees low radon levels and improved health.

In order to ensure that the ventilation system is effective, a passive house must be properly insulated and airtight, allowing for minimal air leakages in and out of the building through thermal bridges such as the walls. This means that heat can be kept out during the summer and in during the winter. Windows are triple paned glazing and the whole building is oriented so that shade is received in the summer and low angle sunlight in the winter.

It is an exciting time to be working with the Passivhaus sustainable construction standard. Even though ventilation systems require an extra investment, passive house owners/users can save a considerable amount of money over the long-term in energy savings, with many projects showing how applying the standard can be surprisingly affordable as a new build. A Resolution of the European Parliament in 2008 called for implementation of the standard in all member states of the European Union by 2021. With 2020 as a deadline for all new buildings to be nearly ‘zero energy’, the Passivhaus standard provides architects across Europe with a robust, holistic set of guidelines for achieving this goal.