12 cm is the optimal thickness!

On 1 March 2009 our company launched a broad campaign in Serbia to increase the thickness of facade insulation on buildings under construction or refurbishment. For many years the term "fasadna petica" (a 5 cm EPS board on the facade) had become so established that most people considered it the ideal facade insulation. The truth is quite different: Serbia lies in a European climate zone (zones II and III) where a facade insulation of only 5 cm is anything but optimal — and, as you will see, anything but the most cost-effective investment.

In summer 2011 the Government of the Republic of Serbia adopted the Rulebook on the energy efficiency of buildings ("Službeni glasnik RS", 061/2011), mandatory from 30.09.2012. It sets maximum U-values [W/m²K] for the various building elements, including the facade wall: Umax = 0.30 for new buildings and Umax = 0.40 for refurbishment. From this rulebook and the conductivity of our products we determined that 11 cm is the minimum thickness of our white facade EPS (Austrotherm EPS® AF) that achieves Umax = 0.30 in a new building. In our brochure "Optimal thickness of facade insulation" we compared the effect of 5 cm insulation (until then the most common thickness on Serbian facades) with 12 cm (the first thickness in our standard range above the required 11 cm, which, with the product named above, meets the rulebook).

As the brochure shows, the difference in investment between 5 cm and 12 cm of facade insulation is so small that the thicker solution (12 cm) is the obvious choice. Add that for Serbia's geographical position and climate zones (II and III) the EU recommends 12 cm of facade insulation, and it is clear these recommendations should be followed — all the more since joining the EU has long been Serbia's strategic goal.

Our campaign has run broadly in Serbia since spring 2009. We produced a four-page leaflet for it (photo left) and a wall poster (photo right) for all our partners (building-material dealers) and their yards.

Within this campaign, and independently of it, Austrotherm d.o.o. keeps explaining that the insulating effect of our products depends much more on the thickness of the board than on the EPS grade. Our Austrotherm EPS AF is the "facade EPS", made primarily for insulating facades. Many people mistakenly want one of our denser ("harder") EPS boards on the facade instead — which only costs more and gives no (or almost no) better insulation! Instead of choosing harder EPS (which belongs in floors!), choose a greater thickness of our facade EPS: 12 cm already reaches the optimum. If you can, thicker boards (14 cm, 16 cm etc.) are even better — they are already everyday practice in the EU, even in countries in the same climate zone as Serbia.

Austrotherm d.o.o. also offers grey facade EPS boards enriched with graphite in Serbia — Austrotherm EPS AF PLUS. A 10 cm board of it on your facade gives the same insulating effect as 12 cm of Austrotherm EPS AF (white facade EPS). The reason is that the graphite in the grey EPS stops energy loss by radiation; since radiation accounts for roughly 20% of the total energy loss through an insulation product, Austrotherm EPS AF PLUS (graphite EPS) insulates about that much better than Austrotherm EPS AF.