Our office building is placed in Copenhagen, Denmark.

Our question is which climate zone to use? Is it zone 5, zone 6 or can we use either one of those?

- We are using a simulation Tool (IES-VE) which automatically suggests zone 6 as soon as Copenhagen is picked as location.

- However, according to the ASHRAE Standard 90.1-2007 table B-4 for international climate zone definitions we land in zone 5 with a HDD65F of 6288 hours.