In conjunction with the HomeMatic FHEM and thermostats HM_HM_CC_RT_DN (HomeMatic 105155) just great. The shutdown of the coupled thermostats are to open the window / door immediately and without noticeable time delay (only up to 5 degrees! What has so far not bothered me because the spaces at airing never as far as the cool down would open the thermostats here). The tedious manual turn off the heaters during release which was only too happy to forget sometimes omitted.