Hybrid Car – More Fun with Less Gas

Reflective Attic Liner - Page 2

register ::  Login Password  :: Lost Password?
Posted by W on February 12, 2011, 1:32 am
 

The problem is the attic is currently about R8 insulation.  To go to R38
would take a lot of work and would have various complexities I am trying to
avoid (e.g., electrical wiring, planking of areas with free insulation,
channeling vents on the sides of home, etc).    I'm looking for any
alternative methods for lowering energy use, such as heat shield.

Without additional insulation, I am trying to objectively define whether the
savings of energy during the summer - by lowering attic temperature and thus
thermal transfer to the home - will be offset by additional energy cost to
fight cooling in the Winter from the ridge vents needed to support the heat
shield.

--
W



Posted by m II on February 12, 2011, 3:34 am
 



The problem is the attic is currently about R8 insulation.  To go to R38
would take a lot of work and would have various complexities I am trying to
avoid (e.g., electrical wiring, planking of areas with free insulation,
channeling vents on the sides of home, etc).    I'm looking for any
alternative methods for lowering energy use, such as heat shield.

Without additional insulation, I am trying to objectively define whether the
savings of energy during the summer - by lowering attic temperature and thus
thermal transfer to the home - will be offset by additional energy cost to
fight cooling in the Winter from the ridge vents needed to support the heat
shield.

--
W


This would depend on your local climate. If you have deep sub-zero
temperatures inthe winter adding insulation to you attic would save you big
bucks.

R8 wouldn't even be legal in any wall in most Canadian building codes. Our
attics are typically R50 - R60 in the latest building codes. If you have
cold winters bringing it up to R40 or better would pay back in two
years...they tell people.

Yes you would have to install insulation damns = "Moore vents" (or use you
reflective board for that) to maintain ventilation if you don't want wood
rot and other damage and be replacing your roof, come 10-15 years. We're not
talking shingles here. You may be talking trusses, ceiling joists etc.
Typically only affects the outside eaves lumber where most of the moisture
is from rain and condensation.

mike



Posted by m II on February 12, 2011, 8:07 am
 On 11-02-11 08:34 PM, m II wrote:




forged posting forwarded to idiot's internet provider


mike


Posted by m II on February 12, 2011, 2:26 pm
 


On 11-02-11 08:34 PM, m II wrote:




forged posting forwarded to idiot's internet provider abuse@x-privat.org


http://groups.google.ca/groups/search?hl=en&as_q=&as_epq=GymyBobism&as_oq=&as_eq=&num 0&scoring=&lr=&as_sitesearch=&as_qdr=&as_drrb=b&as_mind=1&as_minm=1&as_miny 03&as_maxd=1&as_maxm=1&as_maxy 08&as_ugroup=&as_usubject=&as_uauthors=m+II&safe=off


mike


Posted by limehand on February 21, 2011, 5:44 pm
 
There seems to be a number of different suppositions at work here.

The assumption that attic venting is necessary denies the fact that
cathedral ceilinged rooms or spaces dont have ridge vents or vents for
obvious reasons, heat loss. The need for asphalt shingles to be cooled
from below is I believe  unable to be substantiated through documented
side by side testing. Metal roofing far superior to asphalt roofing
would be a better choice anyway as a shiny silver steel roof will
reflect infrared eat as silver reflective surfaces do.(If there is any
doubt about this get a sheet of aluminum foil from the kitchen and
hold a lighter to the underside (not directly as this would be
conductance NOT radiation) and check the heat pass through with your
hand.)
There is some debate though about the need for heat over the need to
reflect it. It depends on where you are I expect or if you have a
ridge water tank you wish to heat up to save money producing hot water
for your hydronic heating system. If the attic is living space
accessed by permanent stairs then any heat build up could be vented
with gable end windows.
Conversely if a building has a crawl space then stapling reflective
foil on the underside of the floor joists will save some heat from
being radiated downward to the cold earth below.This is of course
usually tricky to do and will in time become less effective due to
dust etc settling down on it But it does work quite well if the floor
can be sealed above.

regards

Michael Lough







This Thread
Bookmark this thread:
 
 
 
 
 
 
  •  
  • Subject
  • Author
  • Date
please rate this thread

currently rated 4 out of 5 (1 ratings)