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Thermal Bypass and Duct Leakage
Other Areas to Reduce Heat Load on Your Home
- Heat Sources:
-
- LEAKY DUCTS - Probably the most overlooked area on most homes.
If the air in your ducts were water, your attic would probalby
fill up within a few minutes. How bad is it? In California, they
REQUIRE duct testing/sealing be performed with the installation
of a new A/C unit. Read about it HERE. Many
homes (even newer homes) have duct leakage over 15%. In older homes
with metal ductwork, the leakage is usually OVER 50%. Don't waste
your time on radiant barrier or insulation until your ducts are
tight.
Here are some industry study results on Duct
Leakage and other Air Conditioning
Problems
- AIR INFILTRATION - Holes in your home. Once again, think of your
home like a refrigerator. It does not matter how much insulation
you put on it, until you close the door it's going to run all the
time. Can lights, Attic Door, windows, doors, etc. Anyplace air
can get in. SEAL them up!
- THERMAL BYPASS - This is a term for places HEAT is entering your
home. Essentially bald spots in the homes insulation or "Thermal
Envelope"
READ all
about the Thermal Bypass
Checklist at
the EPA/EnergyStar
website. If you have a 2 story home please read the section
on "Walls Adjoining Unconditioned Spaces" section 4.
- ATTIC VENTILATION - Radiant Barrier will reduce the heat getting
in, but you still need good airflow to help carry the heat out.
Attic Ventilation is very simple. HOLES in the top (Wind Turbines,
Static Vents or - NOT recommended - the terrible ATTIC FANS) and
holes in the BOTTOM (Soffit Vents) that are clear and open. You
must
have
BOTH!!
Air
cannot move out unless it can move in from the bottom. Electric
Attic Fans usually just suck the cold air out of your home.
- WINDOWS - I hate to tell you this, but windows and especially
West facing windows are a brutal source of heat gain. AS A RULE
A home's heating/cooling bill is always directly proportional to
the percentage of "Glazing" or window surface area. The
best window has about an R-Value of 3-4. Even low-e double pane
windows are a gap in the thermal envelope that allow heat to enter
or excape. What can you
do? If a window catches DIRECT SUN then solar screens or really
good window film (not the stuff from the home improvement store)
like a nano-ceramic window film like www.HuperOptikUSA.com will
make a HUGE difference.
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214-707-8600 |
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