Residential Cooling Loads - Plug load

[gooutandgetem]

I dont work with residental HVAC designs much.

I have a 800 SF unit with 3 exposed walls (r-6 wall, r19 attic insul). I can up with 1.3 tons (about600 sf/ton).

I used .7 watts per SF lighting and .5 watts per SF plug load. Are these reasonable values for a residental unit?

Is the overall tonnage seen resonable? (I would use a 1.5 ton unit).

 

[IRstuff]

I think that's a bit of an overkill, but it depends on what your customer likes and tolerates. My previous home, at 2200 sf, used a 3-ton, while most of the other A/C wanted to install a 4-ton. The 3-ton probably ran longer and a bit harder, but seemed to do the job reasonably well. The rule of thumb seems to vary from about 500sf/ton to 700sf/ton. Hypothetically, you could get by with a 1-ton system.

TTFN
faq731-376

 

[317069]

check ASHRAE tabls for values, 1 ton I think is enough.
in residential lighting is not ON all the time like commercial, especially in day time.

 

[walkes]

Newer technology using digital scroll compressors in the condensing unit can help if your a/c is slightly oversized.

 

[gooutandgetem]

Great point, this project in in GA, so units that short cycle to maintain temp and don't reduce humidity (latent laod) is a concern.