Roof Ventilation system?

Air conditioning, fans, and anything related to keeping it cool, such as insulation. This would include any posts generally discussing how to keep it cool, such as which types of blocks are better insulators.... ideal wall thickness for keeping an A/C house cool, etc.

Moderators: Sometimewoodworker, MGV12, BKKBILL

Re: Roof Ventilation system?

Postby BKKBILL » Fri Jan 14, 2011 1:06 pm

Since we are having a show and tell this is the fan I put in about four years ago. There is no ducting it just exhausts into the attic space.

On a warm day the blades will start to rotate with just the hot air rising. That's the time to turn it on. The temperature at the top of stairs drops immediately so one would think the air temp. in attic would also be reduced.

Had no problems with this set up and may use something similar on my next build.
Attachments
IMGP3227.JPG
Stairs fan
It's not who you know, it's whom you know.
User avatar
BKKBILL
 
Posts: 2946
Joined: Tue May 26, 2009 10:05 pm
Location: Mae Taeng, Chiang Mai

Re: Roof Ventilation system?

Postby Treysd3 » Sat Jan 15, 2011 3:13 am

So We are going with the CPAC Monier Roof Vent System. We ordered them from Home Mart. Lets pray they are same color as my roof. ha ha

I will post pic when they arrive.

Another Question ???

Is there a certain amount of Sofitt Vents that I should put on my house?

Do I put the vents on just the front or back of house? or on all sides of house? 2 per side. So total of 8 ?

Thank you everyone.
Attachments
02.jpg
My House roof will be similar to this roof
images-2.jpeg
How Many Soffit Vents are needed per house?
images-2.jpeg (3.15 KiB) Viewed 1225 times
ppi_3.gif
ppi_3.gif (3.5 KiB) Viewed 1225 times
ppi_1.gif
Roof Vent system CPAC Monier
ppi_1.gif (10.12 KiB) Viewed 1225 times
Treysd3
 
Posts: 174
Joined: Thu Dec 02, 2010 1:08 pm

Re: Roof Ventilation system?

Postby BKKBILL » Sat Jan 15, 2011 10:12 am

Treysd3 we have done this one @

viewtopic.php?f=40&t=1457

Now jazzman put up a picture of his soffit venting that shows what I think is a good way to go.
It's not who you know, it's whom you know.
User avatar
BKKBILL
 
Posts: 2946
Joined: Tue May 26, 2009 10:05 pm
Location: Mae Taeng, Chiang Mai

Re: Roof Ventilation system?

Postby Treysd3 » Sat Jan 15, 2011 10:13 am

BKKBILL wrote:Treysd3 we have done this one @

viewtopic.php?f=40&t=1457

Now jazzman put up a picture of his soffit venting that shows what I think is a good way to go.



Thank you sir :) much obliged!
Treysd3
 
Posts: 174
Joined: Thu Dec 02, 2010 1:08 pm

Re: Roof Ventilation system?

Postby BKKBILL » Sat Jan 15, 2011 10:25 am

Here is a little more about soffit venting from CPAC. Seems the recommendation is a full-vent soffit


http://www.google.com/url?sa=t&source=w ... vg&cad=rja
It's not who you know, it's whom you know.
User avatar
BKKBILL
 
Posts: 2946
Joined: Tue May 26, 2009 10:05 pm
Location: Mae Taeng, Chiang Mai

Re: Roof Ventilation system?

Postby fredlk » Sat Jan 15, 2011 11:22 am

BKKBILL wrote:Here is a little more about soffit venting from CPAC. Seems the recommendation is a full-vent soffit

A very interesting and relevant article. Thanks for posting it bkkbill.
It started me thinking: do I need a perforated ceiling in my bathroom?
Maybe yes because it is a dropped ceiling.
Maybe no because there is no heat accumulated in my attic space with my white roof.
It seems that the normal stack-principle won't apply in my case.
What is your opinion, perforated or not perforated?
User avatar
fredlk
 
Posts: 5879
Joined: Tue Apr 07, 2009 3:11 pm

Re: Roof Ventilation system?

Postby BKKBILL » Sat Jan 15, 2011 2:05 pm

MGV12 uses solar chimneys to induce natural ventilation in his house and when we visited it seemed to work very well. You always hear the argument that you just draw hot air in from outdoors. Now that always made sense to me but can tell you it was noticeably cooler inside than outside. Another thing he did was to have the lower inlet openings situated close to his Koi pond thereby pulling in cooler air.

It is a shame there were no roof vents higher up in the attic of this experimental house as I think this would have helped reduce heat build up in this space even faster also increasing the stack affect.

Personally think the perforated bathroom ceiling is ugly and overkill. For me a high capacity exhaust fan would give more control at low-cost possibly with a delayed shut-off control.

This article does prove soffit venting and vent stacks are beneficial in hot humid countries.
It's not who you know, it's whom you know.
User avatar
BKKBILL
 
Posts: 2946
Joined: Tue May 26, 2009 10:05 pm
Location: Mae Taeng, Chiang Mai

Re: Roof Ventilation system?

Postby fredlk » Sat Jan 15, 2011 2:22 pm

BKKBILL wrote: Another thing he did was to have the lower inlet openings situated close to his Koi pond thereby pulling in cooler air.

That also happens in my house once all the water features are built. The water is a probable constant 26 or 27 degrees and the air flowing over it will certainly be cooled down.
BKKBILL wrote:Personally think the perforated bathroom ceiling is ugly and overkill.

I agree about the ugly and your "overkill" has helped me decide.
BKKBILL wrote:For me a high capacity exhaust fan would give more control at low-cost possibly with a delayed shut-off control.

I hate the noise plus I will hardly ever use lights - and therefore the fan - in my bathroom because there are so many windows and it should be very light.
User avatar
fredlk
 
Posts: 5879
Joined: Tue Apr 07, 2009 3:11 pm

Re: Roof Ventilation system?

Postby Roger Ramjet » Sat Jan 15, 2011 2:58 pm

Fred,
I don't know where you bought your latest exhaust fan because mine are whisper quiet...less than an air conditioner and only turn on when the hot water shower/bath heater cuts in and you can hear neither. I don't know how the chimney works, but the man in the townhouse across from us has one and it is remarkable the difference in temperature on a hot day. As we don't have the answers, as yet, it might be an interesting experiment when I finally get to the second floor of my house. So far I have an exhaust fan in each bathroom venting through the wall at the ceiling. I might talk to the architect and see what he thinks.
User avatar
Roger Ramjet
 
Posts: 5281
Joined: Tue Apr 27, 2010 12:55 pm

Re: Roof Ventilation system?

Postby BKKBILL » Sat Jan 15, 2011 4:33 pm

fredlk wrote:I hate the noise plus I will hardly ever use lights - and therefore the fan - in my bathroom because there are so many windows and it should be very light.


Unlike BKK where it never gets dark and you can walk around quite easily without turning lights on you might find where you are building that is not the case. At least it's true up in Mae Taeng where it does get dark and seeing stars becomes a treat.
It's not who you know, it's whom you know.
User avatar
BKKBILL
 
Posts: 2946
Joined: Tue May 26, 2009 10:05 pm
Location: Mae Taeng, Chiang Mai

Re: Roof Ventilation system?

Postby fredlk » Sat Jan 15, 2011 4:42 pm

BKKBILL wrote:Unlike BKK where it never gets dark and you can walk around quite easily without turning lights on you might find where you are building that is not the case.

It's pitch black there, but I was talking about using lights in the bathroom during the daytime which is when the most of the water / moisture will be used / created.
And Roger I (almost) always shower without using any hot water.
User avatar
fredlk
 
Posts: 5879
Joined: Tue Apr 07, 2009 3:11 pm

Re: Roof Ventilation system?

Postby dozer » Sat Jan 15, 2011 5:03 pm

The roof vent system by CPAC Monier is used to vent plumbing appliances which is correctly done through the roof (seldom done here though), eg toliets, floor drains, sinks. I don't think it would be very effective as a general vent and haven't seen them used that way.
dozer
Site Admin
 
Posts: 1940
Joined: Tue Mar 15, 2005 4:21 pm

Re: Roof Ventilation system?

Postby otis-a » Sat Jan 15, 2011 7:02 pm

seems the maths favor Dozer answer. See below

we sit on hill side so the thermals we used with my habberdasher side vents 0,50m x 0,50m in middle of each side, also added r12 bat insulation above suspended ceiling
mechanical venting seems worth a try, my concern is to keep out pests, hence the screened approach, also adding insulation between roof and supports- the more capital outlay the less operating cost of ac, in areas of low humidity using humidification of incomming air works well- in denver colorado we never ran ac's just used 'swamp coolers' as very dry in that location- 5280ft or mile high city
Attachments
Scr000358.jpg
U.S. customary units:
where:
Q
= stack effect draft/draught flow rate, ft³/s
A
= area, ft²
C
= discharge coefficient (usually taken to be from 0.65
to 0.70)
g
= gravitational acceleration, 32.17 ft/s²
h
= height or distance, ft
Ti
= average inside temperature, °R
To
= outside air temperature, °R
See also
Chimney
where to park dog when in town? A barking lot... :-)))
User avatar
otis-a
 
Posts: 1206
Joined: Sat Jun 19, 2010 8:26 am
Location: thai/usa

Re: Roof Ventilation system?

Postby BKKBILL » Sat Jan 15, 2011 9:08 pm

dozer wrote:The roof vent system by CPAC Monier is used to vent plumbing appliances which is correctly done through the roof (seldom done here though), eg toliets, floor drains, sinks. I don't think it would be very effective as a general vent and haven't seen them used that way.


Here is what thaifly had to say about these vents I believe he had the vent pipes made up in Stainless Steel.

thaifly wrote:
somdet wrote:No ifs necessary Jazzman. They ARE in the brochure.
To HomeMart everyone!!!
its a gidday to u fellas ITS THE THAIFLY FROM MAE RIM ....the tile which u are talking about is cpac monier...i purchased 6 of them @ 700 baht a pop.... and as i have previosly posted w MONEY WELL SPENT.... as they look real neat and do a job ITS A GIDDAY TO ALL ITS THE THAI FLY FROM MAE RIM


Also attached are a couple of pictures jazzman posted on the same thread. I will be using Triangle Gable Vent on my next build.
Attachments
file.jpg
It looks like you could use a vent up to about 10cm
file.jpg (17.02 KiB) Viewed 1152 times
file-1.jpg
file-1.jpg (39.79 KiB) Viewed 1152 times
It's not who you know, it's whom you know.
User avatar
BKKBILL
 
Posts: 2946
Joined: Tue May 26, 2009 10:05 pm
Location: Mae Taeng, Chiang Mai

Re: Roof Ventilation system?

Postby geordie » Tue Apr 26, 2011 3:40 pm

roof ventilation is in the uk required to refresh the air in the roofspace because we install vapour barriers that will trap moisture and rot the timber
In thailand it is now becoming common to use foil or metalized film to stop radiant heat and therefore no air can escape as easily as it would with a tiled roof
heat builds up even on a roof with no foil its a requirement to let the heat escape through vents keeping the house cooler hopefully
my comments may be wrong but never deliberately
If it aint broke, dont fix it
User avatar
geordie
 
Posts: 3867
Joined: Sun Oct 12, 2008 4:39 am

PreviousNext

Return to cooling systems

Who is online

Users browsing this forum: No registered users and 1 guest