What is the difference between Passivhaus and BREEAM?

 

At a time when energy prices are rising, it is helpful to know about options in the home for reducing energy consumption. From an architectural and design point of view, this equates to much more than having a shorter shower or reducing the time the heating is turned on. Today, there are several ways to deliver a high standard in energy-efficient construction, using well-developed design principles and sustainability assessment methods. We work with two approaches in particular – Passive House and BREEAM (Building Research Establishment Environmental Assessment Method).

RISE Design Studio Passive House London

Passive House – Energy savings of up to 90%

In recent years, there has been growing awareness of the benefits of a Passive House (or Passivhaus). This is a construction concept that dramatically reduces the need for space heating/cooling and primary energy consumption, while at the same time creating good, healthy indoor air quality. In Europe, a Passive House generally uses as little as 10% of the energy used by a typical building, or 25% when compared with the average new build designed for low energy consumption.

A Passive House relies on energy sources from inside the building, such as body heat, light bulbs, heat from the sun, or heat from indoor appliances to create a comfortable and healthy living environment. A mechanical heat recovery ventilation system is used to enable fresh air to enter the building without letting heat out, and allows heat contained in exhaust air to be reused.

For a building to achieve the Passive House standard, there is strong focus on energy conservation, particularly via insulation, air tightness and optimal glazing.  It is quite a simple approach and checking the design and build against the standard is straightforward.

BREEAM – thinking about carbon emissions

Although more complex to apply in practice, the BREEAM standard is concerned with more than energy conservation. The standard takes into account carbon emissions as well as energy consumption, and is more holistic than the Passive House approach. BREEAM considers the environment/infrastructure surrounding the house – good management, water consumption, biodiversity, transport, pollution, waste management, etc.

This broad-reaching approach allows careful master planning of projects, infrastructure and buildings, which is increasingly important in areas where pressure for housing development is high. BREEAM ratings focus particularly on the reduction of carbon emissions, low impact design, biodiversity protection and climate change adaptation, allowing the client or other stakeholders to compare building performance. To date, an ‘Outstanding’ BREEAM rating has been awarded to less than 1% of new non-domestic buildings in the UK and serves to inspire developers and others to improve, innovate and make effective use of resources.

Sustainability assessment at RISE Design Studio

We regularly work with both the Passive House and BREEAM standards, on both new build and retrofit projects. Our recent work that follows Passive House principles of sustainable design has incorporated the use of air source heat pumps, solar panels, airtightness, mechanical ventilation with heat recovery, and additional insulation.

The focus on sustainable value and efficiency makes Passive House and BREEAM certified projects a worthwhile investment, not least for creating a healthy home or work environment with reduced operational costs, and contributing to sustainability both within and outside the home.

Refurbishing homes for net zero – upskilling our design team

 

Refurbishing and retrofitting existing homes is a large part of the challenge of transitioning the built environment to net zero. We are faced with a significant task, especially as every home is different – efficiency measures that work in one home may not be appropriate for another. Retrofitting is also a daunting task for homeowners, particularly in terms of engaging a contractor with the right skills and experience for the job. At RISE Design Studio, we have worked on several projects that have included energy efficiency measures and, as the push to net zero becomes ever more critical, we are working hard to upskill our design team so all our projects are as energy efficient as possible.

Retrofit flat London

Embracing refurbishment

The 2008 Climate Change Act committed the UK to reducing its greenhouse gas emissions by 80% by 2050. The buildings sector accounts for 37% of total UK GHG emissions and, of these emissions, 65% are from the residential sector. As a result, there has been growth in the residential retrofit industry, with buildings being adapted to be more sustainable and energy-efficient. The majority of our existing residential stock requires some level of retrofit to enable the government’s ambitious emissions targets to be reached.

Common measures include improving insulation. A new heating system might also be installed, or double glazing might be fitted. Yet, conserving energy is not the only reason to retrofit a building. Improving indoor environmental quality, reducing dampness and mould will all lead to increased health and productivity levels of residents.

Upskilling our design team

Recognising the increased momentum in London around reaching net zero, we have really enjoyed working with clients on refurbishment projects that incorporate environmental considerations. Modern architects are well-placed to add creativity and innovation into the drive to retrofit existing housing stock, particularly those that may prove very expensive to retrofit. For example, historic buildings such as Edwardian terraces are protected, and increasing energy efficiency can pose a real challenge. However, there are exciting options to retain the façade and rebuild the living spaces within the building.

More and more clients are seeking energy efficient homes and we are fully aware of the important role architects play in helping to reach the government target for 2050. As a result, we have been working hard to upskill our design team to work on these types of projects.

Maximising design benefit

There are several industry standards designed to increase the efficiency of residential property, including the Passivhaus and EnerPhit certifications. A Passivhaus project 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. However, it can be difficult to reach the exact requirements of the Passivhaus standard in a retrofit project.

Recognising this, the Passivhaus Institut has developed the EnerPHit standard for projects that use the Passivhaus method to reduce fuel bills and heating demand. We are working hard to implement this standard in our projects and our design team has developed the skills to align retrofit projects with this approach. EnerPHit takes into account the limitations associated with retrofit projects and relaxes some of the Passivhaus criteria to reflect this. Nevertheless, it is still a very demanding standard and generally results in a building that outperforms a new-build property both in terms of energy and comfort.