HVAC from scratch

My studio plans are posted on another topic under my name. I bought a used 2 ton "all in one" elec. heat a/c unit. I plan to mount it on a separate slab from the bldg. and duct it in. This unit is very over sized for the 600 Sq. Ft. studio. Would there be a problem with having only one supply and several returns to move the air through the rooms? I was thinking that may provide some noise reduction. Do I still need fresh air? If so, what size and type of fan for 600S.F.? Should I mount this fan away from the bldg?

Rod has some very insightful information on the construction forum regarding this exact topic. http://www.johnlsayers.com/phpBB2/viewtopic.php?t=8483

I so want to do this RIGHT from the start. Can you link me to some specific plans for installing the duct, silencers, and fresh air system. Do I need a separate fan?

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=8410 you'll need fresh air in order to breath... :shock: so you'll definitely need to include this plus calculate any load change due to fresh air. although you may not have this issue with the oversized unit, too large a unit can result in short run times and therefore possible wide swings in temp and humidity. I'm working on correcting this in my home because someone thought that 7 tons of AC would be better than 3.5 tons and we only needed 3.5 tons... go figure. you'd think a highly reputable HVAC company would know better. but back in the 80's (before we bought the house) this was the thinking...) I'm spec'ing a new variable speed multiple zone system to keep the refresh, static pressure, air velocity, run time, and economy aspects in balance. there's no single "just use this plan and it will work for you", you have to look at the situation and decide on your budget, comfort, and whatever your HVAC engineer recommends, as well as some of the links provided (and Rod's book), to get a sense of what will work for you.

Agreed... Oversized units not only have those disadvantages, but the uncontrolled humidity can cause mold, and the unit would be very inefficient because it's never given the opportunity to "warm up" and hit its stride. Every HVAC design needs to be totally customized to the unique requirements of the situation. Consider a heat recovery ventilator (HRV) for fresh air.

the HRV is a good idea. I think some of the blower units I'm looking at have something similar built-in (air exchanger) but now I'll have to re-check. here's a link to HRV and how they work. http://www.popularmechanics.com/home_jo ... 75121.html