While energy efficient homes are gaining in popularity, many homeowners still wonder what they actually entail. Expert in the creation of high-performing, energy-efficient homes, Andy Mitchell, Managing Director at 21°, demystifies the concept. Good planning means you can secure the benefits and the best features that make these properties low energy, comfortable, healthy and sustainable.
Through practical elements like airtightness, thermal insulation, and efficient ventilation, Andy explains how energy-efficient homes are far more accessible than many people realise.
An energy-efficient home comprises three main pillars – minimal air leakage, effective ventilation, and a thermally-efficient core building shell (wall, roof, floor, windows, and doors) and connections between them. All of these elements must work together in synergy for optimal results.
In fact, these ‘optimal results’ provide a level of health and comfort that often far exceed what most people have experienced. It’s therefore essential these components are carefully considered as a whole system, rather than being viewed in silo, to guarantee their overall effectiveness.
For example, installing thermally-efficient windows and doors is not enough to foster a comfortable indoor temperature if there is uncontrolled air movement throughout the house.
Airtightness is crucial in preventing uncontrolled air leakage, which can lead to energy loss and increased heating costs. Airtightness is often overlooked, yet accounts for approximately 30-40% of a home’s heat loss. An airtight home helps to maintain a stable indoor temperature and improves energy efficiency.
From tapes and membranes to advanced sealing solutions, airtightness products are essential for creating a well-sealed building envelope.
These solutions should also extend to products such as windows and doors – where not only the frame is well-sealed to the building, but the opening element has gaskets that ensure an airtight seal when shut. Class 4 (BS EN 12207) is the best grade of airtightness for windows and doors These products prevent air leakage which can typically account for as much as a third of a home’s heat loss.
Effective ventilation is essential for maintaining indoor air quality and comfort while also being energy-efficient. Although making our homes airtight is key to improving efficiency, some air changes are still required to stop the moisture buildup. If this is not done correctly it can lead to mould and dust mite issues, as well as the accumulation of other toxic gases such as VOCs.
Mechanical ventilation with heat recovery (MVHR) systems are engineered to provide continuous fresh air while recovering heat from exhaust air, maintaining a comfortable indoor environment and alleviating the need for additional heating, further reducing energy consumption.
MVHR systems provide optimal ventilation, ensuring properties remain fresh and healthy – without compromising on energy efficiency.
For example, in addition to providing triple-glazed windows and doors, we designed and supplied the MVHR system in a new build Passivhaus home project, utilising a Zehnder ComfoAir Q MVHR unit with rigid steel ducting.
For this project 21° worked with oak frame specialists, Oakwrights (also a NaCSBA member), to develop an MVHR system that would work alongside the encapsulation system. The client cited the quality of the products and the precise installation as being “crucial for the airtightness of the project, ultimately contributing to the Passivhaus certification”.
The thermal efficiency of the building elements is integral to overall energy efficiency, reducing the need for artificial heating and cooling by maintaining a consistent indoor temperature. High-quality insulation materials and solutions ensure every part of the home, from walls and the roof to floors and the foundation, is well-insulated.
High-performance doors and triple-glazed windows are also an essential factor in a properly insulated property, as they’re designed to minimise heat transfer and ensure warm air stays in during the winter and out during the summer. Windows and doors should also contribute to the overall airtightness of the home, furthering energy efficiency.
A whole house retrofit in Cambridgeshire springs to mind in highlighting the role of windows and doors as part of wider thermal performance considerations. Here, our client chose inward opening windows, a lift and slide door, a fold-aside door, and two entrance doors (styles PA2 and GR1) from the GBS78 triple glazed timber range. The result was a comfortable, sustainable home that came as near as possible to Passivhaus standards.
At 21°, we believe that energy-efficient homes are not just for the eco-conscious few, but for everyone. By combining high-performance products with the right specifications and integration, homeowners can achieve remarkable energy savings, improved comfort, and a healthier living environment. Whether building a new property or retrofitting an existing one, solutions are available to meet the highest standards of energy efficiency and sustainability.
Energy-efficient homes are characterised by airtightness, thermally efficient building elements, and efficient ventilation, all working together to create a comfortable, healthy, and sustainable living space.
Through advanced construction techniques and technologies, energy-efficient homes are becoming more practical and accessible to all. As an industry leader, we are committed to advancing the knowledge and application of these solutions, helping to build a more sustainable future for all.
MEMBER UPDATE
Church Grove, a Community Land Trust project in Lewisham, London, has welcomed its first families, who were involved in designing and building their own homes.
Co-ordinated by community housing group Rural Urban Synthesis Society (RUSS), the project has taken 15 years to complete from concept, a testament to the resilience and commitment of its residents.
The 250-year lease for the land was signed in early 2020.
The project has seen future residents and local community volunteers work to plan, design and self build elements of the 36 home development in London, including its volunteer-built community hub building.
Architects Shepherd Epstein Hunter, with contributions from Architype and Jon Broome Associates, worked with the future residents to co-design the development.
Organised and overseen by RUSS, the Church Grove scheme has seen a range of local volunteers driving all stages of the process. As such, the residents were involved with forming a group, acquiring land, raising funds, supervising architects and contractors, getting planning permission, and building and landscaping together as a community.
Most residents took on some of the work on their own apartments, with a choice of self build or self-finish. They were also involved, along with other volunteers, on communal elements, such as the community hub (see images).
Because community led housing projects tend to have a long timeline, four of the original group of would-be residents left the project as their circumstances changed during the timeline.
Being a Community Land Trust ensures Church Grove’s homes are affordable, with a range of sizes and tenures that means the homes are available for everyone, including lower-income families.
Residents also had input into how their housing would be managed, and remain involved with regular meetings in the on-site community hub.
The Chair of RUSS, Anurag Verma, said: “This has been a momentous and challenging project, but this community-led organisation has succeeded in creating a sustainable neighbourhood and unique housing model. This shows what can be achieved when ordinary people work together with a shared vision and determination.
“The project has been led by the community from the outset through the design, planning and building processes. The result is 36 homes with four tenure types, fully tailored to the needs of the residents. We hope that other community groups will be inspired to learn from this model and create their own housing to meet their needs.”
As the capital’s biggest community-led self-build housing project, the block has been supported by organisations, including the Greater London Assembly, the London Borough of Lewisham, the Cooperative Development Society, Triodos Bank, and Big Issue Invest. A new public riverside garden and play area is being built as part of the project, thanks to a crowdfunding campaign and a grant from the Veolia Environmental Trust.
RUSS was set up in response to the lack of suitable affordable housing in London. It continues to work to create new neighbourhoods for the local community with an emphasis on local volunteering. It has been awarded permanent planning permission for its Community Hub, which was used a centre for education and training for the self builders and other community volunteers involved on the site.
You can donate to support RUSS’ ongoing work
Image credtis: Andrea Vladova, Ellie Koepke
Dan-Wood, the manufacturer of energy-efficient, pre-fabricated timber frame homes has introduced a new S-Line range of six house designs into its standard offering.
Dan-Wood’s S-Line range takes quality to the next level with features that include unique architectural detailing and extra-functional design elements.
The S-Line has been developed to offer self builders an even more luxurious home at affordable prices, with the same trusted Dan-Wood design and technology that customers expect.
The architectural elements vary depending on your home design and customisation, but the range typically includes:
Windows – create drama with higher sash windows and balcony windows with French balustrades. Corner windows also feature, making the most of the plot, and extra elements, such as an additional stairwell window, flood the home with daylight.
Eaves – Depending on the design, the homes have a choice of eaves to complement the architecture, including minimalist or wider than standard.
Entrances – look out for designs with a cube roof over the entrance complemented by higher external doors to create a statement entrance.
Floor space – the S-Line range features spacious floor plans and a generous feeling of space, thanks to a raised ground floor of 2.67m and concealed joists. Integrated sliding patio doors visually extend the living area and create a seamless connection to the outside.
Luxury bathooms – the range features a spacious bathroom designed as a relaxing retreat, with enough room for a large bathtub, a separate shower and a double washbasin.
Like all standard Dan-Wood designs, S-Line is available with the full turnkey option. This includes the design and associated architectural drawings and the manufacture and construction of the house structure. This includes external and internal decorating and finishes, heating and ventilation systems, stairs, sanitary ware, doors, flooring and plumbing.
Air Source Heat Pumps (ASHP), Mechanical Ventilation with Heat Recovery (MVHR) and underfloor heating (UFH) throughout are all included in the standard Dan-Wood turnkey package.
Once designed, the house is manufactured in Dan-Wood’s factory in Poland before being shipped to your plot on your chosen date. The house itself is then typically constructed onsite in eight to 12 weeks, with a dedicated project manager looking after every stage of the process and taking care of the skilled Polish team of builders.
Main picture: Dan-Wood S-Line design Park 183s
After 30 years of trading as Green Building Store, the building products supplier and high-performance homes specialist has rebranded itself as 21°. The new name reflects 21°’s vision to support customers to create life changing homes that are healthy and comfortable, secured by optimising energy performance.
21°’s supports self builders by advising and supplying a range of products and services to help make their build as airtight as possible, such as by incorporating triple glazing and MVHR.
By concentrating on airtightness, the home benefits from fewer draughts and air that’s free from outdoor pollutants. This enables the home to maintain a year-round ambient temperature with the added benefit of ensuring that the building is ultra low energy.
Andy Mitchell, managing director at 21°, commented, “We’re thrilled to announce the rebrand of Green Building Store to 21°, and our customers can enjoy the same exceptional service and expertise they’ve relied on from us. While we’ll continue to offer advice and guidance for obtaining Passivhaus certification, we’ll also support those not able or looking to achieve full accreditation, but who still want to create a home that’s designed with wellbeing at the forefront.”
“When specified correctly with one another, windows, doors, and MVHR, along with airtightness and insulation, are the core products for optimising for energy efficiency and comfort. It’s this interconnected specification that is key, and central to what we do.”
Image, from left to right: Paul McGurk, MVHR designer, Mark Redmond, windows estimator, Luke Gilman, windows department manager, Tom Heywood, MVHR department manager, Mike Shufflebotham, sales manager.
21° is a NaCSBA member meaning you can trust them on your project.
Find all our members in the – and you can find all our members in the Membership Directory
NaCSBA member Oakwrights is celebrating a quarter of a century helping self builders create their dream oak-framed home. Specialising in green oak for homes, extensions and outbuildings, Oakwrights started with a team of six back in 1999.
Since then the firm has grown, providing perennially popular oak frame homes that marry traditional carpentry with modern technology and fabrication techniques.
Building in green oak, that is recently felled oak (up to 18 months), is a natural and historical building material that is capable of delivering in spades in terms of engineering strength and architectural detailing, as well as being sustainable as it is a natural carbon sink.
As well as having a show home, the Woodhouse, where clients can experience what it feels like inside an oak-frame home, the firm has gone on to build many self build homes, including turnkey homes, and now is involved with custom building on mult-plot sites. It’s received many awards from the industry press, both for the homes but also its systems, such as the 3i panel system. It recently celebrated winning its third award for Webbs Meadows (below), its custom build site, when it scooped The Daily Telegraph Homebuilding & Renovating Award for Best Custom Build 2023 in December.
Oakwrights also has plots available on its custom build sites, such as at Whipstocks and Webbs Meadow, Herefordshire
Below: Tim Crump, Founder of Oakrights, celebrates with the team
The National Self Build and Renovation Centre (NSBRC) in Swindon has launched a new event called Market Day, where many of its exhibitors will be encouraged to be on stand to chat to self builders in a relaxed and informal setting.
Kicking off on Friday 8 March, 10am-3pm, the Market Days will be on the second Friday of each month. The event is being organised following requests from visitors, to give people the chance to discuss projects in detail away from the busyness of the traditional show days.
Plus, visitors will be able to join a free guided tour of the NSBRC’s new-build educational zone at midday.
A list of exhibitors who will be on stand for the next upcoming Market Day is available on the NSBRC’s website, so you can plan you trip to speak to the right companies for your project.
Find out more about the NSBRC’s Market Days
The Right to Build Task Force has published new data that illustrates that not only are self build homes more sustainable than the average new build, but they have a greater beneficial local impact in terms of spend on materials and labour.
This is welcome news that adds weight to the case for a site when it is submitted for planning, contributing to the argument about a site’s impact versus its harm locally.
The National Custom and Self Build Association (NaCSBA) has long known anecdotally that individuals invest more in their own homes in terms of green tech and sustainable methods than mainstream builders, but welcomes the news that for the first time there is data-based evidence to support this.
In terms of building greener, this is mainly due to the fact that self builders invest more than a mainstream builder would as they want a home that’s more energy-efficient and in which they intend to live in for a long time. Equally, they don’t need to factor in a profit margin, unlike speculative builders.
NaCSBA also welcomes the news that the model contributes more locally than speculative building does, as it feeds into local economies – boosting SME businesses and offering training opportunities.
The analysis was conducted by Chamberlain Walker Economics, which used five local authority areas for the research, chosen as they represent a range of types and sizes. These were Breckland Council, Durham Council, Folkestone and Hythe District Council, Herefordshire Council and South Gloucestershire Council.
The Energy Performance Certificates (EPCs) of self build homes in the five areas were reviewed to compare energy usage, in comparison to new builds in these areas.
The research looked at two metrics: average energy consumption and average CO2 emissions. This found that the average energy consumption of custom and self build homes was significantly lower, by 8-42%, while CO2 emissions were also lower, by 7-43%, in comparison to new build local averages.
This adds to the growing evidence of custom and self build as a greener route to housing, such as the survey that showed that more than 50% of self builds have a renewable energy source as their primary heating system.
Using the same five areas, the research examined the economic factors around the local impact of labour and materials for custom and self build. It found that these homes roughly doubled the economic impact of mainstream housebuilding, as self builders buy more materials locally, and also source SME trades for their project.
This equated to self build spending nearly double, at £45 in every £100 spent, as opposed to mainstream housebuilders, who spend £22 on local materials and labour.
This is good news for local authorities, as well as providing a pool of work for SME housebuilders, a group that government is keen to see grow.
Analysis undertaken by the National and Custom and Self Build Association (NaCSBA) shows that there is an at least 64% under-measuring of demand by the Right to Build registers.
The analysis, published in the industry-focused Custom and Self Build Report 2023/24, took a fresh look at the registers, which every local or planning authority in England must host, as set out by the Right to Build legislation (Self and Custom Housebuilding Act 2015).
Looking at a three year period (2019-2022), it found that 83,430 people were interested in pursuing an owner-commissioned home, in comparison to the 29,697 people who had signed up to a local authority register for the same three year period. This shows that the demand reflected by these registers is underestimated by at least two thirds.
For the purpose of the analysis NaCSBA reviewed the postcode data of people interested in custom and self building and compared this data against total numbers who had signed a register. It marked interest as those people who had invested roughly £40 on either a magazine subscription or in attending a self build show, with the associated costs for the entire day. For this it assessed anonymised data from three of NaCSBA’s Gold Partners, Build It, Homebuilding & Renovating and the National Self Build and Renovation Centre (NSBRC).
The Right to Build registers are the go-to source of demand data for local authorities that acts as evidence of those people who want to build locally. This is important evidence that has a positive input into the decision making process around whether a site gets planning – or not.
NaCSBA is aware that there are many frustrations for people around the registers, such as local connection test or a joining fee, which can discourage people from signing, but strongly advises anyone wanting to self build to sign their register.
This is because the registers are starting to feed into appeals that are leading to companies being awarded planning permission for self build sites, when they were originally turned down, as well as contributing to more supportive local policy to emerge to help meet this demand.
However, local authorities should also be considering secondary sources of data for evidencing demand, such as the multiple effect that the registers underestimate demand – as shown by this research. This helps create a fuller picture of local demand.
The National Self Build and Renovation Centre (NSBRC) has released an infographic sharing the data from its 2023 consumer aspirations survey, which finds that three quarters of self builders are over 55.
The research, which is conducted in association with the National Custom and Self Build Association (NaCSBA), is the third annual survey of those interested in self building, made up of users of NaCSBA’s Self Build Portal or visitors to the NSBRC in Swindon. This resulted in the survey capturing the opinions and actions of 759 responses, giving weight to the data.
In line with the sentiments expressed in previous surveys, the data showed that over 90% said they would not buy a new, spec-built home, while over 90% also said that sustainability, including micro-renewables, was a major consideration for them.
Most self builders are between 55-64, with just 1 in 10 under 45. This older age profile has risen slightly over the last three years, but NaCSBA continues to lobby for more opportunities for younger self builders, such as more small sites.
While the average joint household income is £67,000, many people build with lower household incomes, but this is often because they are retired.
Only 40% of respondees said they worked full time.
NaCSBA welcomes the fact that over two thirds of resondees successfully found land to build a brand new house.
Of those who are self building, self-managed is the most common route, with 40% opting to get stuck in.
The spend for plot and build is up, on average ranging between £350,000-500,000. This has gradually been creeping up, in line with other costs going up across the board.
Two-thirds of respondees are using, or plan to use, savings to fund their project. This is typically made up of personal savings and the equity in their existing property.
Timber frame remains the most popular choice of build method for self builders, at 24%, with SIPs/prefabricated systems closely following at 23%. Brick and block was 14%.
There is good news that 4 out of 5 people had heard of the Right to Build legislation and the registers, as previous surveys showed less awareness. Just over half of respondees had signed a local self build register, which remains a vital part of every self builder’s journey.
Signing might not get you the plot you want, but it ensures the council knows you want to build and it has a statutory duty to consider this when carrying out its housing and planning work. NaCSBA encourages everyone considering a project to sign up to their Right to Build. For FAQs about the registers click the link below.
NaCSBA member Potton is celebrating its 60th year in the timber frame business with its first open day in 2024 on Saturday 6th January at its St Neots show centre
The day is a packed overview of the entire build process when building with Potton, ideal for novice and serial self builders. As well as the opportunity to see the range of show homes on the site, visitors can drop in, without an appointment, to have a chat and their questions answered.
Potton’s self-build consultants will be in the Gransden to offer expert advice informally, or with one-to-one sessions, and there is a programme of morning talks visitors can join.
Seminar timetable
10.40am – 11.20am Build & Budget. An overview of the self build process.
11.40am – 12.20pm Timber frame or SIPS Discover the pros and cons of these different build systems and the benefits of offsite construction.
12.40pm – 1.20pm Designing your dream home. A step-by-step guide to designing your ideal home, including the local authority planning context, approvals and tailoring your home to your needs.
Plus on the day, each show house a specialist in it acting as a hub with the: Design Hub in The Milchester, the Land Hub in the Wickhambrook, the Build Hub in The Elsworth.
Plus you’ll get the chance to raise a glass of fizz to Potton to celebrate it’s 60th year!
