CIBSE Heating & Cooling Load Calculations
Get Your Plant Sizing Right
Walker Energy Analysis provides CIBSE Guide A compliant heating and cooling load calculations, modelled in IES Virtual Environment. We work with consultants, architects, developers and contractors across the UK to make sure heating and cooling plant is accurately sized. A solid load calculation is the number everything else in the design gets built on, so it’s worth getting right from the start.
Steady-State and Dynamic Simulation
We calculate loads in IES Virtual Environment, and use whichever method suits the project and the stage you’re at.
CIBSE Steady-state calculations give you a fast, robust heat loss figure at design conditions — the industry standard basis for sizing equipment, and often all that’s needed for a straightforward heating design.
Dynamic simulation models the building’s response over a full year, hour by hour — fabric thermal mass, time lag, and solar gain through glazing with orientation and shading all factored in. This is the right tool for cooling loads, overheating risk, and any project where occupancy, glazing or thermal mass will meaningfully affect peak demand.
We’ll recommend the method that fits your project, or run both where the design calls for it.
Every calculation includes:
- Room-by-room and building-level peak loads
- Full traceability of assumptions – U-values, infiltration, occupancy, internal gains, so the numbers hold up under scrutiny
- Outputs formatted for plant selection, schematic design and Part L submissions
- A live model we can re-run quickly when the design changes
Working at all Design Stages
Concept / Stage 2 to 3: indicative loads to size plantrooms and risers before the design is locked in.
Technical Design / Stage 4: detailed, room-by-room loads for plant selection and coordination with the wider project team.
Design changes: fast re-runs when glazing, occupancy or the envelope build-up moves, so plant sizing keeps pace with the design instead of trailing behind it.
Why Work With Us
We’re a specialist energy consultancy. This is the core of what we do, not a sideline. Every load calculation runs through IES VE as standard, we turn changes around quickly, and results come back in a format your team can use straight away.
FAQs
What software do you use? IES Virtual Environment, the industry-standard tool used across UK building services for both steady-state and dynamic simulation calculations.
Can you calculate loads before the design is finalised? Yes – indicative loads at concept stage are common, refined as the design develops.
Do you cover both domestic and non-domestic buildings? Yes, across residential, commercial, education, healthcare and mixed-use projects.
Does your project need something else?