TM59 OVERHEATING CALCULATIONS

TM59: Overheating Calculations for Residential Buildings is a methodology developed by the Chartered Institution of Building Services Engineers (CIBSE) to assess the risk of overheating in buildings, particularly in residential settings. This is now required for Building Regulations Approval in most new build cases.

TM59 also emphasizes using occupant feedback in its calculations. This feedback allows for a more accurate assessment of comfort levels as it considers the specific needs, preferences, and behavior of the residents.

TM59 focuses on the potential for overheating in buildings by considering factors such as external weather conditions, building design, and internal heat gains. Overheating can be caused by factors like high outdoor temperatures, poor ventilation, lack of shading, and heat produced by internal activities (e.g., cooking, electronics). The standard suggests how to measure this risk and how to mitigate overheating, focusing on both occupant comfort and health and safety.

TM59 outlines two primary approaches for overheating calculations, Dynamic Simulation Method or Simplified Calculation Method. Dynamic Simulation Method (Preferred method but more expensive). This is a more detailed, complex approach. It uses a dynamic thermal simulation tool (such as IES VE, EnergyPlus, or others) to model the behaviour of the building over time.

For simpler projects or those where dynamic simulations are not required, TM59 also offers a simplified calculation. This approach considers fewer parameters and uses approximations to estimate the risk of overheating. Get into contact to today for a quote.