The Whole Home and Nothing But says Darren Evans
The ‘whole home approach’ to energy efficiency is a way of looking at our homes as an energy system with interdependent parts, all of which play an important role in the creation of an energy efficient home. The features and performance of any one part or component – whether it is insulation, low carbon heating or energy efficient windows – are all affected by the rest, and the energy performance is considered a result of the whole system.
Initially, when implementing the whole-house approach, you should first reduce the need to use energy and then use energy efficiently when it is required. By understanding and implementing this approach, it can result in a significant reduction in energy use.
The fabric of a building will play a crucial role in a building’s success or failure. Therefore, a robust and well-designed fabric is key and it must have good levels of airtightness, measures to minimise thermal bridging and an appropriate ventilation strategy. If the structure is built correctly, it will perform as intended whilst meeting and exceeding building regulations.
Minimising fabric heat loss is integral to increasing energy efficiency. Nearly every building in the UK has a heating system so it is essential to understand how the building performs thermally. Understanding and quantifying energy usage, heat loss and air permeability provide the first steps to insulating. This will make the building more comfortable by helping to maintain a uniform temperature and making walls, ceilings, and floors warmer in the winter and cooler in the summer.
Devil is in the detail
The whole-house approach to house design means taking time over the details. For example, junctions should be appropriately designed and constructed as this makes a significant contribution to reducing heat loss. Thermal bridges occur at breaks in insulation at junctions and openings causing heat loss. This ultimately leads to a drop in internal temperature and an increased demand for heating.
When a home is extended, this provides a great opportunity to enhance its energy efficiency, but it is crucial the extension is not seen in isolation. A whole-house approach that takes the existing property into account should be considered. As well as significant savings on fuel bills, an improved Energy Performance Rating can be an attractive proposition for potential buyers.
Simple measures such as filling cavities, insulating lofts or lagging pipes might be overlooked, but will make a substantial difference to overall performance. An owner may want to extend a house to provide a new bathroom or kitchen to enhance a property’s value, however, if the project does not address the whole house in the process then they could end up creating one energy efficient room which is let down by the rest of the house. Good detailing at the junction between the existing building and the new extension can significantly reduce heat loss; conversely cutting corners on the building fabric of extensions can be a false economy if property owners end up spending more money to heat a poorly insulated or detailed extension.
Deliver energy efficiency from the outset
Once the best possible standards of insulation and airtightness have been achieved, other parts of a home’s energy system can be scrutinised. For example, a heating system should be adequately sized to meet the demand of the building. Under or oversized heating systems will consume much more energy than boilers correctly sized to match the anticipated space and domestic hot water demands. As part of the entire upgrade of the thermal envelope, the installation of high-performance windows and external doors will also impact on a building’s overall thermal efficiency and airtightness.
In order to deliver a positive change in the way buildings are built, we must ensure a new focus is put on whole-house approaches to addressing the fabric first and deliver energy efficiency from the outset. This approach will not only achieve compliance, it will bring tangible financial, health and wellbeing benefits.
For any support on your projects regarding energy and sustainability, please get in touch with Darren Evans Assessments Ltd at www.darren-evans.co.uk
What are yout thoughts on the ‘whole home approach’? We hear so much about fabric first, commonly known as a great marker for energy efficiency, share your comments in the forum below, email us or tell the world on Social Media use the hashtag #Insulatenetwork