High velocity HVAC

[thcri]

</font><font color="blue" class="small">( As long as you DON'T use a central return? I thought that it was supposed to be a major advantage with these systems that you only needed one return per zone. I take it that you end up with hot and cold spots with the single only return?

Ed )</font>

Ed,

Yes you can install a single whole house return. It says to do that in the installation manual even. My experience is, if you want to eliminate noise split the return up system some and it will help with noise. It is just our experience.

murph

 

[PineRidge]

<font color="blue"> Notice that I didn't call it Junkatrol </font>

At one time lots of technicians in my area referred to them as Janijunk. The manufacturer did clean their act up however.

 

[keeney]

If you are building new and have the freedom to put in larger ductwork, I would say to do it that way instead. All the same techniques to reduce noise can be applied to conventional ductwork and since you are starting with a velocity 4x to 10x lower, it will be that much more quiet.

If you are going radiant heat and the forced-air is only for cooling and filtration, you will optimize the placement of the ductwork for cooling. That means putting the supply and returns in or near the ceilings, not the floor or the baseboards.

You could put the air handler in the attic (common in warm climates), but from a noise point of view, I think its best to put it in the basement. This also avoids any issues with condensate drainage being plugged and dripping on things.

The placement in the ceiling plays into the main advantage of the high velocity systems for dedicated cooling - the smaller lines are much easier to insulate in the attic than larger conventional duct work.

However, I would try to avoid the issue of ductwork in the attic as much as possible. Returns can be in central partition walls (still up near the top). Supplys can be run up interior partion walls, flanking the exterior wall (presumed heat load of windows on that wall) from both sides.

Even in the areas where it is unavoidable to put ductwork in the attic, it can still be hard-smooth conventional square or round duct. Both can be insulated easily. They just don't come in a box with the insulation already applied. You have to slide it over the pipe sections as they are assembled.

I would avoid a single, central return unless your house has no doors that close between rooms.

- Rick