Have been doing "the Google" re Roof Space Ventilation. There is a variety of devices and claims. Some can be installed in 5 minutes but you have to have them installed by the company ($900 ea +).
Has anyone had any experience with them ?
As the Summer is approaching any OZB wheeler and dealers able to source a good price for the OZB groupies.
Thanks in advance.
BH
Solar Fan Roof Ventilation - Product Experience & Advice
Lboo hoo on 09/11/2016 - 09:11
Comments
just came across your post,interesting idea,one.question,if the exhaust fan is hanging on a rope,wouldn't it swing when fan kicks in?do you have pictur of your set up?
The rope is very short, and the attached ducting holds it in place. Honestly the rope is not needed, just an idea I had to avoid annoying vibrations.
Sorry I don't have any pictures
thanks.
Thanks for the info klaw81,
You raise some valid points and they are expensive. I'm reasonably handy and will have a look into your suggestions.
kind regards
BH
Pretty much useless I'm afraid, unless your running your house at sub zero temperatures on a 45c day. That said, I put a whirly wig on my mums roof just to make her happy, but its a novelty at best.
Appreciate your comments but I think if there is some outlet for the "hot air"
it must alleviate the ambient roof temp and let the insulation work better in stopping heat from the ceiling.
regards
BHI live in bris. I was wondering about some sort of trap door on roof that could be opened closed with internal ropes. Then some solar powered air intake fans in the eaves. Hot air rises, so sucking in 30~40degree outside air will push the trapped in hot roof air (bloody hot) up and out through the trap door. Unfortunately my roof is asbestos so I can't touch it. The theory is there (somewhat).
Or/and install chimney/pipe out of the roof with a small electric turbine inside. Hot air rises up through the chimne,y which turns the turbine to generate power, to drive an intake fan in the eaves, which pulls in cooler air, which forces warm air up, which pushes air up through the chimney, which powers the turbine etc.
Paint the chimney/pipe black to heat the air inside it more so air travels faster more power.
Again, nice theory. - called a solar chimney turbine
Hi altomic, here is a link to explain the theory.
https://www.google.com.au/search?q=solar+attic+fan&client=fi…thanks .
found a nice scientific paper on solar chimney turbines -http://solar.org.au/papers/01papers/P935.pdf
Thks
Hey guys, those are some interesting theories. Anyone have any more experience with the buyable roof ventilation methods as I'm not that handy with tools?
I was having a look around this website 'Roof Ventilation Blog' www.roofventilationblog.com.au
Especially this chart here: http://www.roofventilationblog.com.au/roof-ventilation-alter…, there seems to be a lot of different options & solar might make it cheaper in the long run but would they really work?
Well found sam18oz, will have a read.
In my quest for the "holy ventilation" issu,e an alibaba supplier has provided this quote to Brisbane. (ie total of 10)30W, 10 pcs, shipped to shipped to Brisbane by sea
product price:
SFM-F30, 30W, 10 pieces, $135*10=$1350
2，wooden case package fee: $82
3，inland freight： $85
4，Customs fees and documentation fees：$50/BILL
5，Insurance fee： $20/BILL- VGM fee: $15/BILL
Total: USD1602 to Brisbane port (Destination local charge: about 295 USD)
average cost of a 30W unit: USD189.7
I looked into these a while back, in the hope that I could reduce the cost of AC during hot days. The theory was that if I could reduce the temperature in the house by a couple degrees by reducing the attic temperature, I could wait longer before turning on the AC, and reduce how hard it had to work.
My main concerns were:
a) You need to cut a hole in your roof (compromised waterproofing)
b) They're expensive
c) Many of them don't actually move a lot of air
In the end, I took a different route.
I bought a large interior-grade exhaust fan with a duct connection from Bunnings for $35, and an exhaust venting kit (silver flexible ducting + external vent grating) for $25 from eBay. Then I got a simple mechanical timer from Coles for $8. Total price: $70.
I mounted the exhaust fan in the very peak of my attic space, hanging on a short piece of nylon rope to prevent vibration transferring to the frame. I connected the flexible duct to the fan, and routed it to the eaves of the house. I cut a small hole in the eaves and connected the external grille to the duct. The fan motor was plugged into the timer and connected to a power point in my roof space.
The fan runs from 10am to 4pm every day. It only uses 18W and removes about 450m3/h of hot air during operation. I have solar panels on the roof anyway, so it's effectively free. I don't have any definitive measurements of the drop in attic temperature, but it's definitely a lot more comfortable to be up there - I'd estimate around 10 degrees lower. I switch the whole thing off during winter.
The best part is that I didn't have to cut a hole in my roof, so I have zero waterproofing concerns, and I could install the whole thing myself with rope, zip-ties and a screwdriver.