Operational carbon
Retrofitting existing buildings with better insulation, glazing and heating systems etc allows us to radically reduce the amount of energy used to run buildings. This means a more comfortable environment and lower energy bills for occupants, but it also means that the amount of carbon dioxide produced in the operation of buildings is greatly reduced.
A huge number of buildings in the UK are very poorly thermally insulated, meaning that heat is lost very quickly and needs to be constantly replaced. These buildings were constructed at a time when fuel for energy was relatively cheap and there was little or no concern for the environmental impact of burning fossil fuels to heat them. From our current perspective we can see how expensive this approach really is. Fortunately, modern construction offers us the opportunity to have far better thermal comfort throughout the year with less energy needed to achieve this.
Air source heat pumps
Air source heat pumps (ASHP) can be a good way to switch to using clean renewable energy to heat your home. They are powered by electricity (either from the national grid, or on site electrical generation) and are an extremely efficient way to heat buildings. Approximately 3kWh of heating energy can be produced for every 1kWh of electricity used to power the ASHP. However, we believe that installing them without first carrying out other upgrades to the building fabric is not a sensible approach. If the heating demand is not first reduced, the ASHP may struggle to heat the property, or will need to be oversized for the property to compensate for the heat losses. In addition, electricity is expensive per unit compared to natural gas, so a simple swap from a gas boiler to an ASHP could increase your fuel bills.
Clients who improve the building fabric of their properties and swap to an ASHP can massively reduce the amount of CO2 produced to power their homes, by around 80 - 90%, even when using electricity from the national grid. As time goes on and the national grid decarbonises, this will improve further until theoretically the electricity produces will be totally renewable (zero carbon).
The anticipated reduction of carbon dioxide emissions is something that we model as part of our BFRA (Building Fabric Retrofit Assessment) report.
Click below to read more about this service.
Graphic comparing a typical Victorian property’s space heating demand with current low energy building standards (AECB, EnerPHit and Passivhaus)
RIBA 2030 Challenge
We want to reduce the impact of the projects that we work on upon the environment and to help clients do the same, so we encourage all clients to help us take on the RIBA 2030 challenge. As part of the RIBA Challenge, we are committed to attempt to meet ambitious but achievable energy, water and embodied carbon performance targets
It is important to clarify that the RIBA Challenge does not seek to replace or replicate a sustainability or an environmental assessment. There is no associated certification procedure. Instead, the RIBA Climate Challenge presents a set of performance outcome targets for projects to aim towards. Therefore, the Challenge has only two requirements for signatories: the first is to attempt to achieve the targets. (There is no penalty or consequence for projects that miss the Challenge’s voluntary performance requirements.) The second requirement is to submit anonymised project data. Clients are therefore requested to provide actual energy and water usage data one year after project completion via the project architect to the RIBA. These figures should be taken from energy/water meter readings (or energy/water bills) for the building over a year so that both winter and summer seasons feature in the calculation. Clients are asked to make this information available to project architects, whose responsibility it is to submit the data report.
Although it is heartening to see how much we can reduce our impact on the climate by taking these steps, if we are to make a meaningful difference to the impact that the construction industry has on the climate, and move towards net zero carbon, we must consider both the carbon cost of constructing the building in the first place (or the materials for retrofitting it) as well as heating, lighting and powering it in use. This is known as the embodied carbon. You can read more about our thinking and approach to this below:
