Hazel Tree Passive House has won the 'Best Eco-home' category at the 2023 Build It Awards. Wahooo!
The judges praised the design for its super-low energy demand as well as the use of natural materials of low embodied carbon. Achieving such high standards of energy efficiency with a relatively modest budget required a simple and compact design that made the most of out a small space.
Conceptually, the house is inspired by a hazel nut, with a warm and soft inner environment protected by a tough outer shell. The nut opens to revel the inner environment; where an atrium and glazed gable make the space warm and light with the timber structure expressed alongside the earthy and cosy clay plaster.
Our clients Janice and Colin had this to say about the design process:
Hazel Tree house is Modest, Calm, Contemporary, Joyful, Light & Airy, Eco-friendly and Blends into the landscape…. These are the words we investigated during the briefing stage with Josh. This was a fun process that helped us all reveal the vision for the house so that an initial concept could be designed. Our house has evolved from this initial meeting, onto paper, and finally into the real world. Now, I can look around from the comfort of the sofa at the architecture that has been born out of these words: The clean diagonal of the roof overhang provides shade from the summer sun and a place to sit out and connect to the landscape. The large area of south facing glazing brings lovely warm light which helps to heat the house in the winter. The atrium allows appreciation of the well crafted timber structure and enables that light to push deeper into the plan and us as a family to connect on multiple levels, making the place feel spacious without being big at all. The simple pitched form with low eaves and black crinkly tin roofing sheets minimises the visual impact on the landscape and creates a rural yet contemporary aesthetic. Like a hazelnut, this is a modest house with a thick shell and a warm heart. We couldn’t be more happy with the outcome, and indeed the journey we took with Josh to get here.
Hazel Tree House achieved Passivhaus certification demonstrating exceptional levels of energy efficiency and comfort. We carried out the rigorous energy calculations in the early stages to inform the design, and to ensure the Passivhaus standard could be met within the site constraints and budget. The house is heated by just two towel radiators! Most of the time the passive heat from occupation and beneficial solar gains is sufficient to heat the space. This is due to an incredibly air-tight (n50) of 0.135h-1 @ 50Pa) and insulated shell, the careful placement of windows and shading devices, and the overall form of the house.
The form is simple with a rectangular plan and pitched roof which contains the first floor rooms; meaning that the dwelling has a relatively efficient ‘form factor’. A large area of south-east facing glazing brings helps to heat the house in the winter via solar gains, whilst being shaded by the overhanging roof and hazel tree in the summer months. The hazel tree thus forms an important relationship with the house, both conceptually and for solar control, as well as it’s important contribution to the biodiversity of the site.
The house resolutely employs a variety of natural materials, chosen because of the low embodied carbon, low toxicity, breathability, and the simplicity of thermal bridge free detailing. You can read more about this here.
I believe that the success of the project is down to a great team of client, builder (Dai from the Passive House Builder) and architect. I feel we all shared the same vision for the house and a commitment to low-impact living.
Clients Janice and Colin had the following to say about the project:
Being completely new to the self-build world, Josh gathered our ideas for an eco-house, translated them into an elegantly simple and imaginative design that we couldn’t have conceived ourselves and worked with us at each step of the way towards achieving our dream house and Passivhaus accreditation. Always professional and quick to respond, he has guided us through many decisions and hurdles. From low carbon construction systems to solar shading mosquito nets, saving trees, planning strategies, building contracts, negotiating at crucial moments, and even learning on the job to successfully bring the project through the rigorous Passivhaus certification criteria. It has been a pleasure working with him and he has shown a real enthusiasm for our project, providing creative design solutions and good advice at all times.