Nova wrote:
Andrew Barss wrote:
I'm looking for advice and ideas for improving energy efficiency in
my house, especially heat from the roof and attic.

I own an older house in Tucson, and we are trying to do what we can
to decrease our electricity (mostly air conditioning) bills. The
house has a peaked roof, with a low attic that has minimal access. The
attic
has some blown-in loose insulation between the ceiling joists, and
nothing on the underside of the roof itself (and putting anything
there is essentially impossible). We have some degree of venting --
there are small vents on the two end walls near the peak, and two passive
vents
(rotary type) on the roof, about four feet down from the peak.

I've heard various things, some conflicting, about how to better
the situation:

a) blow in a lot more insulation.
b) increase airflow using soffet vents (aka birdboard).
c) do both
d) do both, but with some sort of a channel up from the soffet
vents to above the insulation.

e) tear the roof off, put a lot of money into a high-tech roof
treatment. The curent roof is light-colored shingles,
and in quite good condition.


Anyone living in the Southwest have advice on what the best move is?


Thanks,

Andy Barss

For energy efficiency I would recommend more insulation above the
ceiling rafters.

Roof venting will lower the temperature in the attic crawl space but
the main advantage of proper roof venting is that it extends the life
of the roof. If you do vent the roof at the ridge you should also
add soffit venting at least equal in area to that of the ridge vent
for proper air flow. See:

http://www.roofhelp.com/ventilation_main.htm

Almost totally non-applicable to the OP:
* "Water vapor will condense..." Not in 0% relative humidity
* "Frost will form....." In Tuscon?
* "... problem of mildew..." Meh.
* "Ice dams..." Again, in Tuscon?


http://www.cor-a-vent.com/pdf/balancedventilation.pdf

Commercial brochure on ridge vents. Good explanation (except for the bit
about exhausting hot, HUMID, air).


and

http://www.energysavers.gov/your_hom.../mytopic=11390

Typical government simplistic check-list. Superficial, but good,
suggestions.