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.

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

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.

Architecture and the planet: a crucial moment

 

David Attenborough’s ‘A Life On Our Planet‘ brings into sharp focus the destruction of Earth’s habitats that he has witnessed during his nearly 70 years in broadcasting. There is no mistaking the significant scale of the issues currently faced by our planet. At the end of the film, Attenborough offers us some rays of hope: the power of the right financial incentives to encourage reforestation and renewable energy development; the potential to replenish the seas with fish by protecting our coastlines; the importance of raising the global standard of living to slow population growth. But what role can architects play in tackling the pressing issues such as climate change, biodiversity loss and pollution?

Garden studio RISE Design Studio

Cultivating a circular economy

It is common knowledge that buildings have a significant impact on our environment. In 2014, a European Commission report noted that construction and builing use in the EU accounts for 40% of all energy use, 35% of greenhouse gas emissions, 50% of all extracted material, 30% of water use and 35% of all generated waste.

Armed with this information, it has become imperative that architects consider how their design decisions can reduce the impact of the industry. It is time to move away from the traditional ‘take, make and waste’ system towards a ‘take, make and reuse’ approach – a circular rather than linear economy. Recycling materials becomes paramount, working hard to divert construction and demolition debris from landfill and reusing, repairing or remanufacturing materials where possible.

Burrows road home renovation RISE Design Studio

– This glazed extension to the rear of a house in London used bricks reclaimed during the demolition to create a feature wall in the new space. 

Building in biodiversity

We also now know that plants and trees in our cities play an important role in tackling climate change and improving the health and wellbeing of residents. Green infrastructure – networks of green space and other green features in our communities – is central to quality placemaking. There is a compelling case for developing more natural and semi-natural habitats in our cities, towns and buildings, and architects play a key role in considering green infrastructure in the earliest stages of design.

Mill Hill new build RISE Design Studio Green roof

– Our new build house in Mill Hill features a green roof (along with other Passivhaus principles) to minimise the environmental impact and energy consumption of the house.

Embracing energy efficiency

Increasing the energy efficiency of buildings is a concern that has been increasingly recognised in UK legislation and policy. This may involve retrofitting buildings – using new technologies and materials such as insulation to increase energy efficiency. Conserving energy not only has environmental benefits – improving the quality of the indoor environment and reducing dampness increase health and productivity levels of residents.

Rise-Design-Studio-Douglas-House-ph-Edmund-Sumner-25-600x817

– Our Douglas House renovation features a range of passive and active environmental technologies (insulation, airtightness, solar panels, a mechanical ventilation heat recovery system, rainwater harvesting and smart thermostats).

At RISE, we see the importance of contributing to positive change in the way we conceive, construct and deliver the built world. We have made a serious commitment to reducing the impact of our projects on the environment and creating designs that improve the health and wellbeing of our clients and communities.

What does it cost to extend your home?

 

We’re often asked how much a house extension costs in London. Extending the home is a popular option among clients who perhaps need another bedroom, an office space, or a living area, without the hassle (and stress) involved with moving house. Although home extensions in London generally cost more than elsewhere in the UK, they remain a viable and cost-effective option to create your ideal additional living space and increase the value of your home. In this post, we set out the main costs associated with a house extension project.

How much does it cost to extend your home

Harvist Road Glazed Envelope

Extending into the garden and optimising natural light

You generally have three options for extending your home: single storey, two storey or basement. The construction cost of extending the ground floor of your home (in a single storey) is, as a general rule, between £2,200 and £3,900 + VAT per square metre, depending on the level of the specification you decide on. This is a popular option for extending into the back garden to add a dining area, studio or additional living space. It is also an excellent way to bring more natural light into the property, with the ‘glazed envelope’ (like the one in the above image) making the new space feel very spacious and ‘open’. If you plan to use the new space for a kitchen or bathroom then the cost of the fitting will need to be included (typically expect an additional £10,000 + VAT for a kitchen [low-mid level of specification] or £5,000 + VAT for a bathroom [mid range]).

The value of two floors

A two-storey extension generally costs an additional 50% of the construction cost of a single storey extension. It gives you the option of adding an upstairs bedroom or other room and the investment will seem like good value as once the foundations and other structural supports are in place, you do not need to bear these costs again for the second storey. It is important to note that a two storey extension may impact on the amount of light reaching your garden and may also present additional complexity in the planning process (achieving consent for a two storey is often more difficult that for a single storey and sometimes not permitted at all for example in a Conservation Area).

Going underground

A basement addition tends to be the most expensive option per square metre because of the structural and construction complexity and risk. The construction cost of a new space in your basement in London is likely to amount to between £4,000 and £5,000 + VAT per square metre. The costs may be less if you have an existing basement which may instead need converting or extending partially.

Other costs to consider

In addition to the estimated costs set out above, you will also need to factor in the cost of the professional services that you require, such as an architect and any other consultants that you need to involve – for the majority of projects you’ll need a Structural Engineer, Party Wall Surveyor, Building Control Approved Inspector and sometimes a Mechanical & Electrical Engineer as well as a Quantity Surveyor. This typically adds 15-28% to the construction cost. There are also planning fees (£200 to £300 for a house extension, although some extensions may fall under Permitted Development Rights), home insurance costs, and VAT. The costs of windows, doors and central heating will also be in addition to the costs already listed.

Site access and other constraints

There can also be costs associated with mitigating the constraints of a site. For example, the soil type may affect the type of foundation required or the types of building material that can be used, or there may be trees, drainage or other pipework that need to be (re)moved to allow access. If your property is listed and/or situated in a conservation area, you will need to allow for higher costs overall.

Despite the long list of costs, a home extension can greatly improve your living space and also increase the value of your home by 10% to 30%. We take pride in the home extensions that we have completed for our clients and it is always a pleasure to bring more light and space into the home. You can browse some of our recent residential projects here. If you would like to discuss a potential project with us, please get in touch.

What is retrofit?

 

The 2008 Climate Change Act committed the UK to reducing its greenhouse gas (GHG) emissions by 80% by 2050 (against the 1990 baseline). The buildings sector accounts for 37% of total UK GHG emissions and, of these emissions, 65% are from the residential sector. With this in mind, there has been growth in the residential retrofit industry, whereby buildings are adapted to become more sustainable and energy-efficient, while in the non-domestic market, retrofit can often be part of a larger refurbishment project. The majority of our existing residential and commercial stock requires some level of retrofit to enable the government’s ambitious emissions targets to be reached. In this post, we look at some of the methods available for retrofit and consider the role of architects in the retrofit of existing buildings.

retrofit living spaces

Making homes more energy-efficient

A study in conducted in 2014 estimated that 40 million houses in the EU would have to be retrofitted by 2020 if the reduction of emissions is to stay on track. In general, retrofitting involves the use of new technologies and materials within the home, to increase energy efficiency. A popular and simple example is improving insulation. A new heating system might also be installed, or double glazing might be fitted. There is also the option to carry out a Passivhaus retrofit. Although it is more difficult to reach the exact requirements of the Passivhaus standard in a retrofit project, the Passivhaus Institut has developed the EnerPHit standard for projects that use the Passivhaus method to reduce fuel bills and heating demand.

High performance buildings

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 the building’s users (read more on our blog about sustainable architecture principles that improve health). A retrofit project also presents the opportunity to reassess the accessibility, safety and security of a building.

The role of the architect

Retrofitting the home to increase energy efficiency can have significant architectural implications for the interior/exterior of houses. 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. There are exciting options to retain the facade and rebuild the living spaces within the building. Because architects have an overview of the whole build process, they tend to be well-placed to act as a lead co-ordinator in retrofit projects. If you are keen to implement the Passivhaus method, you are likely to need planning permission as the work may require external insulation or changes to the roof, for example. Again, an architect can help with this.