This guide, prepared in cooperation between APPLiA Hungary, HKVSZ and MAHÖSZ, provides professional information for outdoor installation of residential heat pumps with flammable refrigerants. As a result of changes in EU, and consequently national, legislation, more and more heat pump equipment using flammable refrigerants will be imported and installed in homes. It is therefore of paramount importance to comply with safety rules. This technical document is intended to help you do just that.