res. vs. comm. heat load calc.

[cwog]

how much or is there a difference between calculating heat load between residential and commercial a/c?

[hvac3901]

yes there is a difference, residential is by manual J (generally), and commercial i believe has three different methods (not sure of count). But the size of the install and experience, I believe, is the determining factor which method is used. the quality or lack there of in the structures insulation or envelope is the determining factor for most buildings. some resi's could be much better than equivilent commercial sq. ft. and vice-versa.

or were you wondering if the different methods themselves would derive different tonnages for the same structure?

commercial loads account or have allowances for osa, people, commercial loads, etc. were as residential structures only really by manual J, account for the structure, as i recall. They can be tailored for make-up air and the like but the standard form does not. There are some minor differences but i think both achieve the desired goal otherwise they would'nt be approved methods.

[Edited by hvac3901 on 04-11-2005 at 09:44 PM]