Lots of post recently about attic venting. One of my HVAC units is in the
attic. Would an attic fan help with the HVAC? It gets pretty hot up there,
even with a ridge vent and undereave venting.
This is Turtle.
this is the hottest time of the year and you need to check the temperature up
there at about 3:00 P.M. . Any temperature of 120ºF or more up there is hurting
in the form of heat being transmitted into yoiur duct work to be brought into
First Ridge venting in my opinion is trash because i have seen attic i would
have to go into with temp.s of 140ºF and have ridge roof vent system on them.
Now also here it is nothing to see 100ºF+ all the time and hot sun on the roofs.
Second Even with a Ridge vent. You can add a motorized attic vent and if the
ridge vent holds the temperature down . The Motorized vent will never come on
because of it being run by a thermostat to come on at set temperatures.
This is Ron,
The real issue at hand is heat oppression and I agree with Turtle,
Ridgevents are for the most part a waste of time. But i would go a step
further and offer that electric fans as their presently offered are are
an even bigger waste of money and energy. The issue is understanding
the dynamics of heat. At dawn the roof gets hot, the air in the attic
begins to warm, expand and then rise. Conventional thinking is that as
hot air rises, it will draft through either passive ventilation or
ridgevents, and replacement air will be replaced through your soffit
ventilation. The bonus with a "ridgevent" is that any breeze might
create venturi, and can be that much more efficient. It simply doesn't
work, Heat pressurizes the attic and your soffit vents prove it every
afternoon. Hold up a feather duster to your soffit and you'll see
heated air streaming from them. That pressure literally impregnates
everything in your attic, including the ceiling itself. Heat gain
compounds, once it's allowed to begin it cannot be stopped short of
dusk. 110 volt fans are thermostatically controlled, they start out
behind and never can catch up. In addition over 80% of all fires in
attics are attributable to electric fans shorting out. I seriously
recommend solar powered attic ventilation. It's proactive, It's on at
dawn, before the heat of the day. A properly sized unit (1100 CFM+) can
actually keep heat gain from happening all day long.
If you have air exhausting from the soffit vents then you either have
ductwork problems (leakage into the attic) or attic air exhaust
problems. This isn't normal. You could have a light breeze hitting the
opposite some other side of the house or a lateral breeze across the
side you're on causing a venturi effect. Normally there is a net rise of
air through the soffit. Heat doesn't generate extra air molecules. If
there is air leaving the roof vents then it had to enter somewhere
first. If its exiting everywhere through every opening then you should
probably call ghost busters or get the ductwork repaired.
Any preferences as to makes, mods, etc (other than 1100CFM+),
or,conversely, brands to avoid.
And, how about this aspect of the problem in general:
This is Turtle.
Roy the fellow was speaking about the Electric blower fan type attic fans and in
all cases said the problem was not installed correctly in every cases he made
again them. Everything he said bad about them , was the cause of not enough of
supply air to the fans in every cases he sighted and if they were installed
correctly he would not have a case at all as to say they were bad. Now he does
like Solar type and I can't say bad about them.
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