Part O Overheating Calculations

Fast & Accurate Part O Simplified Method Overheating Assessments

We provide professional Part O (Overheating) simplified method calculations for new residential developments across England. Our reports meet all requirements of Approved Document O (2022) and are accepted by planning departments, building control, and local councils.

If you need a quick and cost-effective overheating assessment without using complex dynamic thermal modelling, the Simplified Method is the approved route—ideal for most low- to medium-rise dwelling types.

 
What Is the Part O Simplified Method?
The Simplified Method is the prescriptive route under Building Regulations Part O, designed to ensure new dwellings limit overheating risk through:

Control of solar gains through glazing limits
Adequate ventilation area (openable windows and vents)
Cross-ventilation assessment
Orientation considerations (North, East, South, West)
Maximum glazing calculations
Shading requirements
Mitigation measures where limits are exceeded
This route does not require dynamic modelling, making it faster and cheaper for compliant building types.

We provide full calculations for:

Houses
Flats
Maisonettes
Conversions (where applicable)
New-build and permitted development schemes
 
What Our Part O Simplified Report Includes
Our reports include every element needed to demonstrate compliance, including:

1. Maximum Glazing Area Calculations
We calculate:

Total glazed area
Maximum allowable glazing per orientation
Adjustments for overheating zones
Single-aspect vs multi-aspect dwellings
2. Ventilation & Openable Area Calculations
Minimum free area requirement
Effective opening sizes
Cross-flow potential
Window type compliance (side-hung, top-hung, tilt-turn, etc.)
3. Shading & Solar Control Assessment
External shading
Recessed openings
Overhangs
Solar protective glazing (if needed)
4. Council-Ready Compliance Summary
Clear tables and diagrams show whether each dwelling type passes the simplified criteria.

 
When the Simplified Method Is Suitable
The Simplified Method under Part O can be used when:

The building is not in a high-risk area
Noise, air quality, and security do not restrict opening windows
Window design meets minimum openable areas
Glazing meets the prescriptive limits
Rooms have sufficient ventilation potential
If these conditions are not met, the design may require TM59 dynamic thermal modelling.
We can provide both.

 
Council Requirements & Planning Expectations
Most councils now require Part O compliance at:

Planning validation stage
Pre-commencement conditions
Building regulations submission
Discharge of conditions (DOC)
Local authorities often request:

A Simplified Method Overheating Calculation Report
Evidence of window opening areas
Clear diagrams showing ventilation strategy
Confirmation that no dynamic modelling is required
Mitigation strategy where solar gains exceed limits
Our reports are accepted by councils across:

London
Manchester
Birmingham
Leeds
Bristol
Reading
Milton Keynes
Cambridge & Oxford
All coastal & high-density planning authorities
 
Why Choose Us for Part O Simplified Overheating Calculations?
✔ Fast turnaround – ideal for planning deadlines
✔ Cost-effective vs TM59 modelling
✔ Accepted by all UK councils & building control bodies
✔ Clear, easy-to-understand compliance summaries
✔ Expert assessors specialising in Part O
✔ Mitigation advice included if criteria are not met

 
Which Documents We Need
To start your Part O Simplified Method assessment, simply provide:

Floor plans
Elevations
Sections
Window schedule (if available)
Site location or orientation
We can complete the full report with minimal information.

 
Get Your Part O Simplified Overheating Report Today
Whether your project needs a fast simplified assessment or you want to check whether dynamic modelling is required, our team can help immediately.

Contact us today for a quote or send your drawings to begin.

Part O Simplified Method | Overheating Assessment
Overheating Calculations Part O | Simplified Compliance
Part O Building Regulations | Simplified Overheating Check
Residential Overheating Assessment | Part O Simplified
 
Fast Part O Overheating Calculations using the Simplified Method. Council-ready reports for planning and building regulations. Glazing, ventilation and shading checks included.

Part O Simplified Method overheating assessments for new homes. Council-approved reports covering glazing limits, ventilation and shading compliance.
Professional Simplified Method overheating calculations for Part O. Ideal for planning, building control and residential design compliance.
Quick and accurate overheating calculations using Part O Simplified Method. Glazing, solar gain and openable window assessments included.