The basic economic terms of typically more straight forward in a Class A Building where the rents are higher.

Base Rent – This is the minimum rent that the tenant owes the landlord either on an annual
basis, a monthly basis, or a per square foot basis.
Additional Rent – This is to account for the increase in the Landlord’s expense over time.
 1) Operating Escalation – This can either be a pro-rata share of the increase in operating
expenses or fixed annual increase of the base rent (e.g. 3% each year)
2) Real Estate Tax Escalation – A pro-rata share of the increase in the building’s real estate taxes.
  Electric – This is typically a separate and additional charge from the rent. There are 3
ways that a tenant can be charged for electric.
1) Direct meter – Pay the utility company directly.
2) Submeter: The landlord charges the tenant based on actual usage, as
measured by a submeter. This cost is based upon what the utility company charges the landlord plus an administrative fee to read the meter.
3) Flat rate: This would typically be $3.35 – $3.50 per sq ft

 After Hour HVAC – In most class A buildings the HVAC runs business hours Monday –
Friday and possibly limited hours on Saturday. If a tenant wants the HVAC non-business
hours than there is a charge to keep the system running. 

In a class A building the nightly cleaning and trash removal are included in the rent.  The electric charges may also be lower if the AC is on a building system.  

Class B & C Buildings
Most of the economics are the same. The base rent, the additional rent, and the electric. However, the
class B & C buildings are typically not full-service buildings and landlords of these properties will add
additional charges on top of the rent. These charges vary from building to building but can add up so need to be carefully evaluated.

Office Cleaning: In a class A building the landlord includes this in the rent. In the B & C
buildings the tenant typically must hire their own cleaning service and contract with a carting service for rubbish removal. A cleaning service can cost $2.00 – $3.00 per sq ft
and rubbish removal can cost $.15 – $.50 per sq ft.
Water/Sprinkler Charge: The B & C landlords will often through this in. The cost can be
anywhere from $.25 – $.50 per sq ft.
Security Guard: Just like the water/sprinkler charge, these landlords will often pass
some of this cost onto the tenants. The cost can be anywhere from $.25 – $.50 per sq ft.

 AC Maintenance: In a B & C building the tenant often has their own AC unit. The upside of this is that the tenant can run the unit whenever they choose. When the tenant has their own unit, it is typical that they maintain the unit and hire a vendor to do so. This cost can
vary greatly depending on the size of the space and the size of the AC unit.

Before you agree to business terms, always make sure your broker clearly explains all of these items.