Warehouses must be considered carefully. The first consideration is whether it is going to be conditioned, cooled and/or heated, or semi heated. Next is the applicable energy code. Older codes did not require the building envelope to meet the energy provisions if the warehouse didn't include mechanical equipment and was unconditioned. In ASHRAE 90.1-2010 and -2013, buildings being constructed must be assumed to be conditioned.
ASHRAE 90.1-2010/90.1-2013 Section 18.104.22.168. Spaces shall be assumed to be conditioned spaces and shall comply with the requirements for conditioned spaces at the time of construction, regardless of whether mechanical or electrical equipment is included in the building permit application or installed at that time.
ASHRAE 90.1-2010/90.1-2013 22.214.171.124. In Climate Zones 3-8, a space may be designated as either semi-heated or unconditioned only if approved by the building official.
One of the reasons for this change, is years ago shell buildings being built did not have to meet the building envelope provisions, however, the intent of these buildings is that later on the spaces would be leased out and most likely conditioned. The expense of bringing an existing building up to code can be very costly especially if portions have to be completely rebuilt to accommodate insulation.
So, if you have a warehouse that is strictly just a warehouse (unconditioned), confirm with the code official as to whether the building envelope must meet the energy provisions even if you are complying to an older code