Unexpected Results when Changing Sensible Heat Recovery for AllAir HVAC System

Hello Ladybug Tools Community,

I have recently started to implement the use of the AllAirHVAC component in my Honeybee energy models - until now I was simply using the IdealAir component.

I have tried adjusting the sensible heat recovery value for the AllAir component, trying out 0 and 0.6.

I am simulating an office building in Queenstown, New Zealand, which is in a heating dominated climate.

When I set the sensible heat recovery to 0, the resulting EUI is 139 kWh/m2/a.


When I set the sensible heat recovery to 0.6, the resulting EUI is 147 kWh/m2/a.


How can the EUI be lower for a building with an HVAC system with no heat recovery, compared to a building that has heat recovery, in a heating dominated climate? On further inspection of the outputs, the cooling output is the only one that changes significantly. Why is cooling changing by about 8kWh/m2/a but heating is unaffected?

I’m a bit confused about what’s going on - please let me know if you have any ideas!