Nenthorn Self-Build: Sustainable Home Design and Living

In the peaceful setting of Nenthorn, Berwickshire, our architects partnered with a forward-thinking couple on a journey to create a characterful, eco-home that prioritises energy efficiency. The project was fueled by their desire to retire in Scotland and their ambition to incorporate meaningful eco-house design features into their new property. Our role was to merge the client's vision for environmentally friendly, inviting living spaces with the realities of planning regulations. Balancing these requirements was key in bringing the project to fruition while adhering to local standards, and the challenge required careful consideration of the home's size, materials, and shape to create a truly sustainable house design.

Interior Architecture and Sustainable Home Design Elements

Central to the environmentally friendly home is an expansive, barn-style living area with vaulted ceilings and an impressive timber-framed window that floods the space with natural light, providing panoramic views across the Tweed Valley towards the Cheviot Hills. This choice enhances the ground floor living space by adding height, character and individuality, while connecting the inhabitants with the beauty of the surrounding natural landscape, promoting a feeling of well-being for the occupants.

Beyond the central living area, the client sought a home office with scenic views to enhance the work environment with a natural feel. They also desired a front deck, reminiscent of an American-style porch, to facilitate casual greetings and interactions with neighbours, embracing the importance of community in sustainable home design. These elements reflect the client's intent to personalise their eco-friendly home and to create a space that prioritises well-being in its living spaces.

Harmonising with the Landscape and Local Architecture

In aligning with local planning requirements, our design ensured the house's ridge height matched that of neighbouring properties, maintaining a sense of architectural alignment in the area. The chosen materials, a slate roof and white render, reflect the village's existing character, with added timber elements introducing a contemporary feel.

Window designs were thoughtfully selected to emphasise verticality, subtly echoing the traditional architecture prevalent in this part of Scotland. By selecting sustainable materials, we aimed to reduce the project's carbon footprint and ensure the environmentally conscious home contributes positively to its natural surroundings.

Our design approach integrated these various elements, leveraging the house's geometry and massing to achieve a unified design. The main roof aligns in one direction, complemented by the distinctive barn roof that projects towards the landscape at a right angle, creating a visually compelling and coherent structure that respects its surroundings while maintaining its individuality.

Energy Conservation Through Prefabricated Construction

The clients wanted to prioritise high thermal efficiency and low energy consumption for their new house, so we used a prefabricated timber frame system from Fleming Homes. This system is designed with high insulation and air tightness levels in mind, aligning with the energy efficiency goals of eco-friendly houses.

Collaboration with a SAP (Standard Assessment Procedure) assessor during the design phase ensured a comprehensive strategy for surpassing the required SAP performance criteria, reducing energy consumption and securing exceptional thermal performance for the home.

This approach laid the groundwork for an eco-house that exceeds energy efficiency expectations, substantially reducing the home's carbon emissions and carbon footprint.

Enhanced Insulation with High-Performance Glazing

The eco-friendly home also incorporates high-performance glazing with a U-value of 1.0, a feature that is helpful in creating more energy-efficient homes. The choice reflects our commitment to sustainable design, as glazing with such a low U-value significantly reduces heat loss.

Historically, this level of thermal efficiency in glazing came at a substantial cost. However, technological advancements and increased market availability have reduced costs to just a 10% premium compared to standard options.

This shift towards more accessible eco-friendly features allows us to improve a home's insulation envelope substantially. Windows, traditionally seen as a vulnerability in thermal performance, are among the strengths of the Nenthorn eco-house project.

Managing Solar Gain for Optimal Comfort

Given the home's orientation on a south-facing slope and the inclusion of the barn-style

living area with large south-facing windows, we anticipated increased solar gain and a risk of overheating in the summer. As a result, the Nenthorn home has been fitted with blinds for solar shading and ceiling fans in the double-height area to help circulate air and keep the space cool during warm weather.

This aspect of house design has become increasingly important with climate change and the evolving building regulations, which now emphasise the need to mitigate overheating risks, a focus highlighted in the 2023 building regulations revision.

Mechanical Ventilation Heat Recovery: Air Quality & Efficiency

Optimising indoor air quality and energy efficiency in the home is achieved through the strategic installation of a Mechanical Ventilation with Heat Recovery (MVHR) system. This innovative system enhances the home's environment by preheating incoming air via a heat exchanger, capturing the warmth from outgoing air to minimize ventilation-related heat loss. Such functionality is key to preserving the home's airtightness while ensuring a steady flow of fresh air.

Located in the garage, the MVHR system is instrumental in regulating the home's temperature, markedly boosting comfort during the winter months. It features a summer bypass option, ensuring the home remains comfortable throughout the year by adapting to seasonal changes. Our adoption of MVHR technology is a testament to our dedication to constructing homes that are not only comfortable and energy-efficient but also promote a healthy living environment.

Wood Burning Stove and Air-Source Heat Pump

The property's heating system further benefits from the inclusion of a wood-burning stove and an air-source heat pump. The wood-burning stove serves as the primary heat source during the winter months, significantly contributing to the home's warmth, while the air-source heat pump plays a supplementary role. This minimal reliance on the heat pump is due to the home's effective insulation and the efficient heat output from the stove.

Given that heat pumps can be slow to react, the system is designed with a thermal store to address the fluctuating demand for hot water. This water tank functions as a 'heat battery,' storing energy until needed, thus ensuring a consistent and on-demand hot water supply. To accommodate this setup, careful planning was necessary to allocate sufficient space within the garage, underscoring the importance of integrating this efficient and responsive heating solution into the home's design.

Achieving Sustainability Through Innovative Home Design in Nenthorn

Incorporating thermal strategies, such as advanced insulation and high-performance glazing, alongside important climate control measures like the MVHR system, our strategy for this eco-home in Nenthorn embraces sustainable design elements to reduce energy usage and create an innovative and welcoming property. Our careful consideration of the home's placement and the integration of eco-friendly features ensures that the house harmonises with its picturesque Scottish setting and epitomises Vellow Wood’s commitment to sustainable residential design. Read our blog to learn more about how we craft high-quality eco houses that minimise environmental impact and maximise sustainable living. Plus, learn more about our eco-homes in Kent and our eco-friendly house in Argyle by visiting our projects page.