Quick question. I have an older house remodel in which I am taking out
the old HVAC system from under the house to install a complete new
system.

My options to reinstall would be either in the attic which would get
really hot. I redid the roof with ridge vents down the length of all
ridges to help with this.

I could install under the house-- however, the crawlspace is really
crampped-- (I wonder how they ever got the original system in unless it
was during new construction.) Yet, there is a tendancy to get a lot of
moisture under the house.

What is your advice in this matter? Attic?? Under house?? Eliminate
the moisture problem?? Ensure I have solved the hot attic problem??

Thanks for any help.

Soffit vents? If not, your ridge vents may be totally useless.

If it's "really hot" up there, I'd look into fan-assisted,
thermostatically-controlled ventilation. I did recently, as did a
friend, and it works great in terms of avoiding roasting shingles and
heating house from above. In your case, you may want the fan blowing in
with exhaust along ridges.

As to where to put unit, I'd ask the installer- you may need all new
ductwork. Furnace may enter discussion, too.

Moisture problem definitely should be addressed, with vapor barrier,
ventilation, exterior swamp drainage, whatever works. DAGS on this and
await a deluge of hits.

HTH,
J

"doof" wrote in message
oups.com...
Quick question. I have an older house remodel in which I am taking out
the old HVAC system from under the house to install a complete new
system.

My options to reinstall would be either in the attic which would get
really hot. I redid the roof with ridge vents down the length of all
ridges to help with this.

I could install under the house-- however, the crawlspace is really
crampped-- (I wonder how they ever got the original system in unless it
was during new construction.) Yet, there is a tendancy to get a lot of
moisture under the house.

What is your advice in this matter? Attic?? Under house?? Eliminate
the moisture problem?? Ensure I have solved the hot attic problem??

Thanks for any help.

Can not see the installation from here. Call some local pros and ask them.

Hey doof,

I've owned my own HVAC business for about 28 years and think I have a
pretty good idea of what you should do.

Fix the water/moisture problem under your house, then put some vapor
barrier (plastic, 4 mil) on the ground, then put your ductwork back
under the house, use metal trunk line with metal ATDR take-offs/taps,
either flex or metal for the lines and return, insulate ALL metal
with 2" foil backed ductwrap after you screw and tape all seams.

I've done thousands of systems in middle tenn, in both attic and under
floors, unless the house is on a concrete slab, or it's a two story, no
way would I put it in the attic.

Also, about attic ventilation, I would not live in or have a home
without POWERED ATTIC VENTILATION, I've had to work in attics when the
temp was 180, after several tests I have performed with attic
ventilation, Powered Fan Ventilation more than pays for the 1 to 3
cents per hour the the fans use compared to the 25 to 50 cents the a/c
compressor uses.

A very good site to find out more info is
http://www.buildingscience.com/

Have fun,
mrkool