Since moving into the house back in March the internal temperature measured in our hall way running through the center of the house has consistently remained between 21 and 23 degrees. Here is a picture of our simple hall termostat showing current and min/max temp. This was for at least a 6 week period.
We have found that the roof over-hang is vital in preventing over-heating in our south facing living areas during the all too rare hot sunny days. The overhang provides shading when the sun is at its highest point during summer. In autumn/spring and winter when the sun sits lower all of the sun is needed for solar heating.
Our REC-Temovex Air handing unit has a bypass facility to disable Heat recovery. This is necessary during very hot spells when there is no requirement for it. We find that on some evenings during warm weather it is good to open our utility room window as this is the hottest room in the house. This allows a lot of the heat to escape quickly.
I took some pictures of the Temperatures displayed on our Temovex today. The first picture shows the temperature of the fresh air in the supply air duct (15 degrees). Fresh air is drawn into the house via a vent on the west gable.