With the growth of living standards, there is an increasing demand for the cooling of living space. Rational energy use demands the use of alternative ways of cooling because the energy consumption of compressor cooling is high. In this article a new cheap and efficient paperboard compact heat exchanger and indirect evaporative cooling are presented. Indirect evaporative cooling is the most suitable way of cooling for low energy buildings especially if combined with heat recovery ventilation system. Operation simulation of an indirect evaporative cooler installed in a low energy house is also shown.