Passive House/Passivhaus space heating demand criteria (kWh/m2/yr)

Hi All,

I’m currently running a parametric simulation of different input variables using colibri, and wanted to use the Passive House ‘annual space heating demand criteria’ as one of the output variables to optimise.

I’m currently using an ideal air loads HVAC system in the simulation, and normalising ‘heating’ output from the EPResult component to get kWh/m2/yr.

Is this output reporting what I hope it to be? Or should I be obtaining this figure from another source?

I know @edpmay has explored Passive House criteria through honeybee in the past - any way you could clarify this please?

Hi @jwoodall,

For whatever its worth - as far as I know you are correct. When I’ve used HB tools to evaluate Annual Energy Demand (in PH lingo) that can be approximated using Ideal Air Loads and then the outputs you’d look at in the ‘in.csv’ result file are:

  • “Zone Ideal Loads Supply Air Total Cooling Energy” ( = Annual Cooling Energy Demand)
  • “Zone Ideal Loads Supply Air Total Heating Energy” ( = Annual Heating Energy Demand)

Note though that the PH certification targets for both PHI and PHIUS use a ‘conditioned floor area’ (net interior, excluding walls and columns over a certain size, etc…) rather than a ‘gross floor area’ as their reference dimension for certification targets - so just be aware of that when normalizing the zone’s gross energy demands you’d need to calc TFA/iCFA yourself rather than use the HB Zone’s gross floor area. For some buildings we’ve worked on (office) the gross and the net-interior floor areas can be off by as much as 20-30% depending on the internal configuration.

For details on the TFA/iCFA protocols in case you are interested:

There are a couple other places where the PH model protocols are quite different than HB/EP, but that gross-floor-area vs. net-floor-area is the biggest one to pay attention to IMO. (the other main one would be to set heating set point to 20°C and cooling to 25°C, then not use any setbacks)

hope that helps,

@edpmay thanks so much for the swift response. Clarification much appreciated, and point noted regarding treatment of flood areas when normalising.