Getting conflicting advice - save me!!

[Big Ed]

The rule of thumb is used on the estimate only. Once you sell the job then spend the time designing the system...

[41gasman]

Brianmu.
Hey I was out driving in the rain
today and your project was running
around in my head.One of the things
that gets done alot is using the
brand new heating system to keep
the house warm during constuction.
Do NOT let this happen.You would
not believe the crap that I find
in the ducting.But by far worst
than that is the dust.They keep
the house pretty darn hot when
the sheetrock goes up.With all
the dust that is created from
the mudding,tapeing,sanding,
and saw dust to.This stuff get
into everthing.And in a big
way.Filters or not.If anyone
disagrees just point them to
the manuals.Most all manufactures
will void the warranty if this is
done. We don't want that with
those nice new variable speed
air handlers now do we!!!
Have them use there own space heaters.

In regards to return air ducting.
Do your best to avoid panning
off floor joists.They are almost
never sealed well.And invite dirt
and dust in to the system.Remember
returns operate under a negitive
pressure.And are usually not very
well insulated.Something that gets
missed a lot during inpection.
If at all possibe use metal ducting.
Thanks for your time.
41Gasman