a guide to XA

H4 Residential Dwelling KwaZulu Natal

We have done Rational Designs on literally hundred’s of properties in South Africa over the last 4-years covering every classification of project type in every climate zone across the country. It’s a fascinating journey understanding the rocket science of how any property might respond to its specific location in relation to the architectural design, orientation and effectiveness of shading on walls and windows.

On this journey we have seen specific standards of performance establish themselves with houses on the different residential estates in the KZN coastal belt and we have seen these require quite different construction technology solutions than properties located in Hillcrest or Pietermartizburg or Hilton or further inland in Mooi River for example (which are all assumed to be in the same climate zone according to the Regulation). Even on a tighter scale we see that Dunkirk Estate properties perform very differently to Zimbali Estate properties for example and require quite different approaches to their construction technologies in demonstrating regulatory compliance, rather because of the effectiveness of the architectural style that is inherent between the two estates.

What’s always quite astonishing is the substantial energy load that is (sometimes) imposed on dwellings when the prescriptive high-performance glazing is substituted for a single-glazed clear-glass design solution in a hot climate zone. An extensive amount of deep analysis and solution-finding has to be brought to any project in order to engineer those energy savings back into the dwelling so as to ensure that they are indeed as energy efficient, thermally comfortable, and as compliant as the SANS 10400XA Building Regulations would call for them to be.

Rational Design energy modelling isn’t just about magically ‘making XA go away‘ and single-glazed clear glass seem possible (as many assessors simplistically do), it is also about competently assessing thermal comfort, internal room temperatures and the electrical loads (and ongoing running costs) that any house will endure for its lifetime. It’s about helping you ensure that you are developing the best architecture for your client!

Besides heating and cooling, the energy embodied in the hot water generation is the single largest consumer of energy (and cost to the client) and so it becomes a vital part of the Rational Design assessment to accurately measure this and bring about energy savings that can help offset the gains caused by reducing the window specification.

The below Case Study is a beautiful example of both exquisite architectural aesthetics and optimised building performance. Rather than just simply seeking to ‘satisfy’ the Building Regulation at a minimum compliance level we rather competently found ways to optimise building performance in hand with minimising capital cost of construction… Better architecture built cheaper…!

(email us for a full copy of the Case Study)



Incompetent Rational Design Energy Modelling

What happens if you submit an ‘incompetent’ Rational Design Energy Report…?

By virtue of Regulation SANS 10400A A19 it is the obligation of the architectural professional to adequately provide sufficient information to satisfy the Building Control Officer that competency is being delivered and the requirements of the Building Regulations are being achieved.

If the Building Control Officer has doubt as to the integrity of the submission he/she has the authority to refer a rational design for what is called a ‘rational assessment’ – the rational design is recalculated by an independent third party, at the clients expense, so that the accuracy of the initial report can be verified.

In what is largely an unregulated industry the competency of energy modelling services in the current marketplace is not an assured certainty. As in any form of business, deal with people you know and trust, and do not be swayed by the simplicity of cheapest price!

Educate your clients to understand that when possibly developing a multi-million Rand investment that saving a couple of grand on ‘competent person’ energy modelling is not necessarily always going to serve them well when levels of thermal comfort, long term energy efficiency and all the related electrical running costs may be ill-considered and specified.