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Marmite the Dog · 13-05-2008, 11:03 AM

Quote:

Originally Posted by Bruce

And I've seen them spinning on windless days.

No you haven't.

Just because there isn't any noticeable wind at ground level doesn't mean there isn't any at roof level.

Smithson · 13-05-2008, 11:56 AM

Quote:

Originally Posted by Bobcock

If you say so...

answer me this though....

If the air you want to move is what is making the 'fan' move, what is the point of that fan????

The job of a fan is to move air from A to B.

If the hot air in A is moving to B on it's own and driving a fan what is the point of the fan??

Clear now?

I suppose the fan is there because if you just put a hole then the rain would come in. Even if it was covered birds etc might get in. There is more wind higher up, so they may work better than just a hole

Also it spins, which looks good. They are probably worth the money as I can't think of a cheaper alternative, but I think there are better ways to ventilate your roof if you were building a new place.

They are popular is Aust, but there's plenty of wind there. If you really want to check on the effectiveness there is probably some Australian research that has the answer.

lom · 13-05-2008, 12:46 PM

Quote:

Originally Posted by Smithson

Also it spins, which looks good.

Yes, so you can look at it and tell yourself "Holy cow, that was a good investment, I can see now how much hot air it is pumping out of my attic" .
And your neighbors will see it, will think "that's a fantastic thing", and then buy one..

lom · 13-05-2008, 12:49 PM

Quote:

Originally Posted by Bruce

Its the difference between the outside air and the interior temperature which creates the air current, not whether there is any wind outside.

Allright.. But tell me, where does the energy come from, the energy needed for spinning the turbine?

Smithson · 13-05-2008, 01:03 PM

Quote:

Originally Posted by lom

Quote:

Originally Posted by Smithson

Also it spins, which looks good.

Yes, so you can look at it and tell yourself "Holy cow, that was a good investment, I can see now how much hot air it is pumping out of my attic" .
And your neighbors will see it, will think "that's a fantastic thing", and then buy one..

Impressing friends and neighbors is a big factor when building. If this can be done for 2K+ then it's a good investment.

Bobcock · 13-05-2008, 01:13 PM

Iom

I don't have to, that is not my statement, despite you crediting it to me.

lom · 13-05-2008, 01:21 PM

^ Quote corrected, sorry

Bobcock · 13-05-2008, 01:24 PM

Smithson.

A louvred vent would do the same job in a NO WIND condition. In fact it would do a better job in a NO WIND condition (less resistance to air flow)

As I have said, these will work better in windy conditions than a straight vent, what we are disagreeing with is luckydogs nonsense that in a NO WIND condition his fan is happily spinning away sucking out warm air, which is wrong on two counts.

1. The air flow created by warm air rising is not strong enough to drive this, it is outside wind.
2. If the warm air is driving the fan, then what is the point of the fan? A fan is there to move air NOT vice versa.

It doesn't even need HVAC knowledge to understand this, just common sense.

Bruce · 13-05-2008, 01:35 PM

The reason its better with the ventilator is that without the ventilator the hot air can't escape, but with the ventilator the air can find a path out, so that creates an air current as the hot air rises.
I can look out the first floor back window of my Thai townhouse down onto the roof of the kitchen below, which is between two rows of townhouses so there is little wind movement, and see the ventilator spinning below me, but there is no breeze coming in my first floor window above it.
Its not about whether roof insulation is better than a ventilator. I support both.
Still, if you're happy being hot, stay sceptical.

Bobcock · 13-05-2008, 01:44 PM

You are still saying that the air is driving the fan.....what is the point of the fan then?

Louvred upstand, less resistance will perform better in the conditions you say.

Bruce · 13-05-2008, 02:22 PM

Louvres are also good. The ventilator is up high in the roof so empties the hot air out of the roof which is good.

Smithson · 13-05-2008, 02:45 PM

Quote:

Originally Posted by Bobcock

Smithson.

A louvred vent would do the same job in a NO WIND condition. In fact it would do a better job in a NO WIND condition (less resistance to air flow)

I understand I was only joking.

13-05-2008, 04:51 PM

Quote:

Originally Posted by Bruce

Louvres are also good. The ventilator is up high in the roof so empties the hot air out of the roof which is good.

You tell 'em Brucey baby. I am bored with all their stupid theoretical utterings.
WE know it works. THEY do not! So WHO BLUDDY WELL CARES?

NickA · 13-05-2008, 06:16 PM

Cool, over the last week, I too have noticed a 5 degree drop in temperature in my house and I didn't even bother installing an extractor fan.

Bobcock · 13-05-2008, 09:07 PM

Quote:

stupid theoretical utterings

The voice of a Pattaya bar owner.....55555555

buad hai · 14-05-2008, 06:46 AM

Quote:

Originally Posted by NickA

Cool, over the last week, I too have noticed a 5 degree drop in temperature in my house and I didn't even bother installing an extractor fan.

Same here. Just thinking about installing one has worked wonders....

Seriously, I've been wanting to put my remote sensor up in the attic so I can get a real-time measurement of the difference between the attic, ambient and room temperatures but it's been so cold I'd probably have to put on a jumper before venturing up there....

Bobcock · 14-05-2008, 07:02 AM

Doubtless the cold air outside falling through the fan has had it spinning like a top.

Bruce · 14-05-2008, 05:01 PM

Just think, if you'd hada ona these thingies it might have been 10 degree cooler instead of only five.

hillbilly · 14-05-2008, 05:19 PM

You guys can laugh, but I believe there might be something to this idea...

Besides, I like being a trendsetter!

lom · 14-05-2008, 07:08 PM

^ Got a scientific explanation for your beliefs?

13-05-2008, 01:24 PM	#68 (permalink)
Bobcock Llandewi Brefi's Finest Last Online: Yesterday 05:30 PM Join Date: Feb 2006 Posts: 4,673	Smithson. A louvred vent would do the same job in a NO WIND condition. In fact it would do a better job in a NO WIND condition (less resistance to air flow) As I have said, these will work better in windy conditions than a straight vent, what we are disagreeing with is luckydogs nonsense that in a NO WIND condition his fan is happily spinning away sucking out warm air, which is wrong on two counts. 1. The air flow created by warm air rising is not strong enough to drive this, it is outside wind. 2. If the warm air is driving the fan, then what is the point of the fan? A fan is there to move air NOT vice versa. It doesn't even need HVAC knowledge to understand this, just common sense. __________________ Can't win on a compromise, I'd rather lose on my own. TEAK DOOR FORUM - 'Giving wackjobs a voice'

13-05-2008, 01:35 PM	#69 (permalink)
Bruce Saraburi Join Date: Apr 2006 Posts: 269	The reason its better with the ventilator is that without the ventilator the hot air can't escape, but with the ventilator the air can find a path out, so that creates an air current as the hot air rises. I can look out the first floor back window of my Thai townhouse down onto the roof of the kitchen below, which is between two rows of townhouses so there is little wind movement, and see the ventilator spinning below me, but there is no breeze coming in my first floor window above it. Its not about whether roof insulation is better than a ventilator. I support both. Still, if you're happy being hot, stay sceptical. __________________ "If I knew what I was doing, I'd be doing it right now." Keith Urban

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13-05-2008, 01:13 PM	#66 (permalink)
Bobcock Llandewi Brefi's Finest Last Online: Yesterday 05:30 PM Join Date: Feb 2006 Posts: 4,673	Iom I don't have to, that is not my statement, despite you crediting it to me.

13-05-2008, 01:21 PM	#67 (permalink)
lom #&§~ Last Online: Today 12:07 AM Join Date: Jan 2006 Location: Dark side of the room Posts: 5,234	^ Quote corrected, sorry

13-05-2008, 01:44 PM	#70 (permalink)
Bobcock Llandewi Brefi's Finest Last Online: Yesterday 05:30 PM Join Date: Feb 2006 Posts: 4,673	You are still saying that the air is driving the fan.....what is the point of the fan then? Louvred upstand, less resistance will perform better in the conditions you say.

13-05-2008, 02:22 PM	#71 (permalink)
Bruce Saraburi Join Date: Apr 2006 Posts: 269	Louvres are also good. The ventilator is up high in the roof so empties the hot air out of the roof which is good.

13-05-2008, 06:16 PM	#74 (permalink)
NickA This is not my avatar Join Date: Oct 2005 Posts: 11,396	Cool, over the last week, I too have noticed a 5 degree drop in temperature in my house and I didn't even bother installing an extractor fan.

14-05-2008, 07:02 AM	#77 (permalink)
Bobcock Llandewi Brefi's Finest Last Online: Yesterday 05:30 PM Join Date: Feb 2006 Posts: 4,673	Doubtless the cold air outside falling through the fan has had it spinning like a top.

14-05-2008, 05:01 PM	#78 (permalink)
Bruce Saraburi Join Date: Apr 2006 Posts: 269	Just think, if you'd hada ona these thingies it might have been 10 degree cooler instead of only five.

14-05-2008, 05:19 PM	#79 (permalink)
hillbilly Still trailer trash Last Online: Today 05:54 AM Join Date: Jun 2005 Location: BKK & 'D&G Resort' Posts: 6,616	You guys can laugh, but I believe there might be something to this idea... Besides, I like being a trendsetter!

14-05-2008, 07:08 PM	#80 (permalink)
lom #&§~ Last Online: Today 12:07 AM Join Date: Jan 2006 Location: Dark side of the room Posts: 5,234	^ Got a scientific explanation for your beliefs?

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