A renewable system only pays for itself if it is sized against how the building actually uses energy. Specified from roof area alone, arrays are routinely too large for the demand underneath them and the export is worth a fraction of the self-consumption.
Because the renewable design sits with the same team as the energy model, the demand profile it is sized against is the modelled one — and the resulting contribution feeds straight back into the Part L and NZEB calculation rather than being bolted on afterwards.
Who this is for
Projects meeting a renewable requirement
The renewable contribution is part of the Part L and NZEB calculation, so it is worth establishing early what the building needs rather than sizing a system to fill a gap at the end.
Commercial and industrial sites
Larger loads change the economics considerably. Demand profiles are modelled first, then arrays and storage sized against them.
Schemes considering a heat network
Solar thermal and district heating are assessed alongside PV rather than treated as separate questions, so the comparison is made on one set of numbers.
How the process works
- 01Establish the demand profile from the building model
- 02Assess the site and the technologies that suit it
- 03Size the system against measured demand, not roof area
- 04Optimise storage and, where relevant, heat network connection
- 05Feed the result back into the energy and compliance model
Frequently asked questions
How do you size a solar PV system?
From the building’s modelled demand profile rather than from available roof area. What matters to the return is how much of the generation is used on site, and that is a function of when the building actually draws power.
Is battery storage worth adding?
Batteries raise the share of generation used on site, which is where the value is. Whether that justifies the cost depends on the demand profile, which is why the optimisation is done against the model rather than by rule of thumb.
Does renewable generation count towards Part L?
Yes — the renewable contribution forms part of the Part L and NZEB calculation. Designing the system alongside the compliance model means the contribution is accounted for properly rather than estimated.
Are you tied to any installer or supplier?
No. The design and feasibility work is independent of installers and equipment suppliers, so the specification follows the analysis.
Other services
Energy performance and BER
Domestic and non-domestic BER, Part L and NZEB compliance modelling, and IES thermal modelling — from baseline assessment through to SEAI registration.
02Overheating analysis
Dynamic 3D thermal modelling to CIBSE TM59, TM52 and TGD-020 — identifying overheating risk early enough to design it out rather than mitigate it later.
03Daylight and building performance
Daylight, thermal comfort and CIBSE load modelling — Radiance and IES analysis used to improve comfort, evidence compliance and size the plant properly.
04Planning and sustainability consultancy
Climate Action Energy Statements, Sustainability Reports, Building Lifecycle Reports and the supporting technical analysis a planning application needs.
05LEED, BREEAM and WELL certification
Accredited across all three systems — certification strategy backed by energy modelling, credit tracking and technical consultancy, from one point of contact.
Talk to the team
Tell us about the project and the stage it is at. We'll set out what the analysis would cover and what it would tell you.
Request a quote