Hello Everyone,

I am not sure this is the right forum to ask this type of queries. In the
ASHRAE climate classification, the climate zone (1 to 8) are based on CDD
and HDD on base temperature 10 deg C and 18.3 deg C respectively. In the
literature, the 18 deg C as base temperatures for both CDD and HDD have
been used for different classification systems around the world.

My question is regarding to methodology of defining base temperatures for
heating and cooling need of the building.

1. How ASHRAE arrived on base temperature of 10 deg C for CDD?
2. For classification of international cities should it be different?

Any help and guidance will be appreciated.

Thank you.

Regards,
Mayank Bhatnagar