The new Building Regulations Part O 2021 Edition is the first of its kind and will tackle overheating in new residential type buildings only.
The overarching goal of Part O is to encourage the design and construction of buildings that limit unwanted solar gain during the summer months and provide occupants with adequate means of removing excess heat from indoor environments.
It is important to note the measures themselves are not designed to guarantee the comfort of building occupants but to protect an occupant’s health/welfare.
The goal of Part O is to limit unwanted solar gains within summer and provide adequate means of quickly removing excess heat from indoor environments.
In mainland Europe the concept of dealing with summer over heating is nothing new, with buildings being designed accordingly, but in the UK it is now a necessary consideration given the increase in summer temperatures due to climate change.
Part O only applies to new residential buildings. See paragraph 0.3 of Approved Document O where this is explained further. Conservatories on new residential buildings must meet the requirements of Part O
Part O does not apply to extensions or conservatories added to residential buildings after they are built.
Part O does not apply to buildings undergoing a change of use.
Whilst it is not a requirement to submit a Part O Assessment at Planning Application stage, consideration should be given to it, otherwise there is the possibility that the design needs to be amended further down the line, which may require changes to the planning approval which would add time and cost to any project. For example, it may turn out that external solar shading is required, or the size and configuration of the windows needs to be changed.
It is important to balance the need to provide adequate levels of daylighting inside a new dwelling with the potential risk of overheating, therefore dwellings should be designed to provide an optimum level of daylighting whilst not giving rise to the risk of summer overheating.
In some locations the potential for opening windows for ventilation may be limited due to noise and air quality issues along with those of security, in these instances it will be especially important necessary to consider the issues alongside the ventilation strategy and mitigating overheating in the first instance.
By addressing the issues of summer overheating at an early stage it is possible to avoid costs and delays further down the line, it also allows for the optimum solution to be developed so that the design maximises natural light and views.
By designing for an optimum level of natural light and to take advantage of view, it is also possible to minimise the amount of glazing in a property which will reduce cost and also improve the thermal efficiency of the building as solid walls perform significantly better than even triple glazed windows at retaining heat and mitigating overheating.
Julian is a director of BB Partnership, an Architect with over 25 years of experience and also a Certified Passive House Designer, with an extensive knowledge of both planning and construction and a keen interest in sustainable development.
I hope that the above information has proved to be useful, at BB Partnership we believe that our experience of working on schemes all the way through to completion allows us to consider all aspects of a project at an early stage to ensure that our planning schemes can be successfully delivered.
Please contact us for more information.