In the last blog I outlined the Energy Hierarchy required by the London Plan, this week we’ll be looking at the first step - be Lean. If you’re submitting your planning application for a major development, in this part of your Energy Strategy you’ll need to demonstrate that compliance with Part L 2013 is achieved through the use of efficient building fabric (fabric first) and services, without the use of renewable energy or district heating systems. But you don’t need to stop there; the greater the improvement over the TER from building fabric, the less investment you’ll need in renewable energy or district heating.
So what do we mean by fabric first?
For residential developments you can consider measures such as increasing insulation to walls, floors and roofs, reducing air leakage and reducing heat loss from thermal bridges. In many instances you would need to model thermal bridge heat loss as there are no standard psi values for the bespoke constructions often seen in London apartment blocks.
The efficiency of your lighting design is paramount and you should use low energy lighting throughout the development. Mechanical Ventilation with Heat Recovery can also be an effective means of ventilating a property, whilst minimising heat loss. MVHR may also be essential to maintain indoor air quality, especially for developments adjacent to main roads. For non-domestic developments, similar principles apply, although the impact of your services design is greatly increased. You need to focus on LED lighting where possible, heat recovery if you are using mechanical ventilation and high efficiency heating and cooling systems. Avoid the use of electric heating systems where possible as the high carbon factor for electricity can make compliance a challenge.
For both domestic and non-domestic developments solar gain is a large influence. In residential developments, solar gain will reduce your heating demand in winter and lower carbon emissions. However, you need to be careful not to allow too much solar gain, as this could create an overheating risk in summer. This can be controlled through the g value of the glazing, which determines how much solar radiation penetrates the glass, along with shading measures.
For non-domestic developments, look to reduce solar gain if comfort cooling or air conditioning is being provided. Excessive solar gain will increase the cooling demand and subsequently carbon dioxide emissions. Adopting these measures should show you how to how achieve compliance with Part L 2013 and the first step of the London Plan Energy hierarchy. If you’ve achieved a further reduction over the TER here, then it’s only good new, as you’ll need to invest less in renewable energy or district heating. Look out for our next blog on the Be Clean step of the Hierarchy where we’ll cover off district heating networks and combined heat and power.
But if you can’t wait till then and have a burning London Plan question, get in touch on 020 7129 8123.