Part O Simplified
Overheating Method

Overheating Risk Analysis for Dwellings

Building Regulations Part O

Part O Simplified Method Overheating Analysis

The government has introduced Approved Document Part O of the Building Regulations to prevent overheating in buildings including dwellings, care homes and student accommodation.

Compliance Routes

Two Ways to Demonstrate Compliance

Approved Document Part O introduces two routes to demonstrate compliance with overheating requirements:

Route 01

Simplified Method

Limits solar gains and provides a means of removing excess heat through window sizing or window design. A prescriptive, calculation-based approach.

Route 02

Dynamic Thermal Modelling (TM59)

A standardised approach for predicting overheating risk for residential buildings based on CIBSE TM59 methodology.

Learn more

Compliance Measures

Two Key Compliance Measures

Compliance is based on designing and constructing the building to achieve both of the following:

Limiting unwanted solar gains in summer Controlling solar energy entering through windows and glazed elements to reduce internal heat build-up.

Removing excess heat from the indoor environment Providing adequate ventilation and heat removal so occupants can cool the building effectively.

Limitations

Situations Where the Simplified Method Cannot Be Used

Although designers can choose either method, there are situations where the simplified method cannot be used:

i. Buildings with more than one residential unit using a communal heating or hot water system with significant horizontal distribution pipework.
ii. Buildings in locations where external noise means windows will remain closed, thereby minimising ventilation.
iii. Buildings in locations where pollution prevents occupants from opening windows.

In such situations — or where the simplified method fails — dynamic thermal modelling should be used.

Dynamic Simulation

How Can We Help You?

We can assist you in carrying out the overheating risk assessment using the simplified method to demonstrate compliance with Part O. For projects where the simplified method is not suitable, we can carry out the overheating risk analysis using dynamic thermal modelling.

Send an Enquiry

01332 492082

07886 277818

Send us an enquiry

11 Caithness Crescent, Derby DE22 3XS

Part O SimplifiedOverheating Method