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Energy Modelling

Any new building or substantial renovation will require energy modelling in order to comply with building regulations and, in some councils such as Bath and North East Somerset, planning policy. We can help you navigate what type of energy modelling you require and at what time to comply with the necessary policies and guidelines of the modern construction industry.

PHPP Modelling

We carry out PHPP modelling in-house.


The Passivhaus Planning Package (PHPP) is a sophisticated energy modelling software tailored for the Passivhaus standard, which emphasises ultra-low energy consumption and high thermal comfort in buildings. Created by the Passivhaus Institut in Germany, the PHPP is an essential tool for designers and architects aiming to achieve the stringent requirements of the Passivhaus standard.

  1. Input Data: The PHPP process begins with the collection and input of comprehensive data about the building. This includes architectural details, insulation levels, window specifications, ventilation system efficiency, and more. It's essential that this data be as accurate as possible to ensure valid results.

  2. Energy Balancing: Using the data provided, the software calculates the annual energy demand of the building. It evaluates the balance between energy gains (like solar gains through windows) and losses (like transmission through walls or ventilation losses).

  3. Verification: The software then verifies if the modelled building meets the Passivhaus criteria. For a building to qualify for the Passivhaus Standard, its heating demand should generally not exceed 15 kWh/m²a, and the primary energy demand should not be above 120 kWh/m²a.

  4. Optimisation: If the building does not meet the criteria, designers can use PHPP to adjust various parameters, such as improving insulation or changing the window type, to see how these changes affect the building's energy performance.

  5. Component Selection: PHPP includes a comprehensive database of building components, such as windows, doors, and ventilation systems, that are certified for use in Passivhaus projects. This helps designers choose appropriate components for their designs.

  6. Detailed Outputs: The software provides detailed outputs, including monthly energy balances, peak loads, and internal temperatures. This granularity allows for fine-tuning of the design and system sizing.


The PHPP software is a rigorous, detailed tool for energy modelling in line with the Passivhaus standard. It's both a verification tool and a design guide, helping architects and engineers create energy-efficient, comfortable buildings.

Solar Panel Yield Calculations

Solar photovoltaic (PV) panels are devices that convert sunlight directly into electricity. Made primarily of semiconductor materials like silicon, they capture photons from the sun and release electrons, creating an electric current. Solar PV panels play a crucial role in on-site energy generation, allowing homes, businesses, and other facilities to produce their own electricity. This decentralised energy production reduces the reliance on fossil fuels, mitigates greenhouse gas emissions, and lessens transmission losses. On-site solar generation also provides consumers with increased energy independence, reduces electricity costs over time, and offers a sustainable and renewable energy solution, aligning with global efforts to combat climate change.

Local Planning Authorities are increasingly demanding that on-site energy generation is taken into account at planning stage. In Bath and North East Somerset, applicants are required to submit calculations that demonstrate what yields could be expected from solar arrays on new residential projects. We can provide this service in-house using a variety of specialist tools.

SAP, SBEM and BRUKL Modelling

SAP (Standard Assessment Procedure) is the UK's official methodology for assessing the energy performance of residential buildings. SBEM (Simplified Building Energy Model) does the same for commercial buildings, providing consistent evaluations of a building's energy consumption and carbon dioxide emissions. BRUKL (Building Regulations UK Part L) modelling is an output document produced using SBEM, showcasing a building's compliance with Part L of Building Regulations, which pertains to energy efficiency. All three tools are pivotal for achieving building regulation compliance in the UK. They ensure that new constructions and significant renovations meet the necessary energy efficiency standards, supporting the nation's sustainability and carbon reduction goals.

Navigating what modelling to commission and when can be confusing. This is especially the case given that some councils now also require PHPP modelling for certain types of building.  We can take the lead on this; sourcing the necessary expertise for clients to gain consent and compliance.

BANES Local Planning Policy SCR6

Policy SCR6 pertains to new build residential developments in the Bath & North East Somerset district. It mandates such developments to target zero operational emissions by reducing heat and power demand and then meeting all energy demand through onsite renewables. Key requirements for these developments include:

  1. Space heating demand under 30kWh/m² per annum.

  2. Total energy use below 40kWh/m² per annum.

  3. Onsite renewable energy generation equivalent to total energy use, favoring roof-mounted solar PV.

  4. Connecting to a low- or zero-carbon district heating network if available.

Developments should submit an energy assessment in line with the Sustainable Construction Checklist SPD to demonstrate compliance.


We can: 

  • use our expertise to design a policy compliant building from the outset

  • provide the necessary energy modelling in-house using PHPP

  • provide on-site solar PV yield calculations

  • support your application with architectural design advice 

  • collaborate with your architect to assist in achieving compliance

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