Got questions about BEPIT? Check out these FAQs. If the answer isn’t here, get in touch.
What, in essence, is BEPIT?
It’s a facilitated service offer where a construction expert, through meetings and workshops with your team, will review and improve design, procurement and construction
When and why do I need to use it?
BEPIT can help you if your project requires good ‘as built’ energy performance – as part of planning conditions, client aspirations or critical energy balances/ district heating systems. The earlier you bring us in the more effective our service can be. New homes generally turn out to have significantly worse energy efficiency performance than they are designed for. You can benefit from BEPT because we’re experts in understanding what causes this performance gap and how to close it.
How much time and money will it cost my company?
We tailor our service to your needs with project specific proposals. The whole process is managed and facilitated by us, meaning that beyond short attendances for critical personnel (~45min per briefing), there is very little time or training requirement. Typically, our service ranges between 18-25 person days. Our fee structure is £700 per person day.
Who in my company takes responsibility for using the toolkit?
The process is generally arranged through the project director or sustainability lead of the main contractor for a housebuilding project, and coordinated with the design manager on the project. Often our service is requested by the client but paid for by the contractors as part of the project fee.
What is the performance gap and how big a problem is it?
The performance gap is the difference between predicted and measured dwelling energy performance, generally evaluated using whole house heat loss tests. Most industry research estimates the performance gap to be around 50%* (UK average), meaning the tested (‘as built’) heat loss being 50% greater than the predicted heat loss. This larger fabric heat loss can be reflected through increased heating energy requirements to make up the shortfall.
For recent research on the performance gap, see this paper from Leeds Beckett University’s Centre for the Built Environment.
How can impact be measured?
The overall impact of BEPIT can be measured through air permeability testing, ventilation fan power, thermal imaging, heat flux and co-heating tests (whole house heat loss tests).
Air permeability testing is most helpful when staged at shell completion and after services installation (pre tack), to give feedback on air infiltration levels.
Ventilation fan power use can be estimated by isolating the appliance on the main fuse board and by counting electric pulses for a set time period (pulse meters only).
Thermal imaging, heat flux and co-heating rely on a heated fabric, so come relatively late in the construction process. They also require low external temperatures to work. The results are very useful but the tests are more difficult to implement. Thermal imaging can highlight major fabric weaknesses, whilst heat flux testing can give the as built point u-value at that location. The result of a co-heating test is given as a heat loss coefficient (HLC), a measure of heat loss through the fabric as a whole. With modifications, this figure can be compared to the as built stage Standard Assessment Procedure (SAP) heat loss coefficient.