whirlies....
- Thread starter BMan
- Start date
Whirlybirds
Hubby installed 2 last week in son's roof he has insulation but not sarking, yes they do help a bit we wer aiming to reduce heat in garage as he keeps house locked up when at work.
Now I was at Woolworths Masters store after we installed whirlybirds and they have a model with an internal fan for $120, we paid $75 for coloured whirley birds and plain were on special for $59
Regards
Sheryn
Hubby installed 2 last week in son's roof he has insulation but not sarking, yes they do help a bit we wer aiming to reduce heat in garage as he keeps house locked up when at work.
Now I was at Woolworths Masters store after we installed whirlybirds and they have a model with an internal fan for $120, we paid $75 for coloured whirley birds and plain were on special for $59
Regards
Sheryn
It helps quite a bit. I think they are very effective. Make sure the bearing is good, so you don't get a constant annoying little squeak.
One of these....
http://www.ascentonline.com.au/html/products_gallery/roof_ventilation_products_gallery.html
One of these....
http://www.ascentonline.com.au/html/products_gallery/roof_ventilation_products_gallery.html
It does help, but the insulation helps heaps more. I put insulation and a whirlybird.
thanks i may get some whirlies then
it has some really old sisolation stuff (like the alfoil stuff) but its got what looks like foam or something inbetween its about 15mm thick and is falling down so probably pretty useless now and even counteracting what its meant to do
the roof is just zincalume iron but old and dull
i want to get insulation but if i do it while its getting rented out could it be claimed as a deductible expense?
and drawback in winter with the whirlies? sucking too much hot air out and making it too cold?
it has some really old sisolation stuff (like the alfoil stuff) but its got what looks like foam or something inbetween its about 15mm thick and is falling down so probably pretty useless now and even counteracting what its meant to do
the roof is just zincalume iron but old and dull
i want to get insulation but if i do it while its getting rented out could it be claimed as a deductible expense?
and drawback in winter with the whirlies? sucking too much hot air out and making it too cold?
i have put 2 in and dont really notice a difference during the day
have found in the morning the place seems cooler but could be from colder nights who would know, being stone that keeps releasing heat all night im sure there doing something
i probably require 3 or 4 to notice a benefit as those little holes compared to the roof size is nothing really
have found in the morning the place seems cooler but could be from colder nights who would know, being stone that keeps releasing heat all night im sure there doing something
i probably require 3 or 4 to notice a benefit as those little holes compared to the roof size is nothing really
I think they are a waste unless you try to improve their performance.
They are there to draw the heat out not suck in fresh cooler air.
You need to add vents under the eaves to get a flow happening.
And they are not going to work on a hot stinking day with no wind.
They do cool the roof space down quicker when the southerlies arrive.
I think you would be best to put in solar vents which can be expensive.
http://solarvent-px.rtrk.com.au/
http://www.solatube.com.au/residential/product-catalog/solar-star-roof-ventilation/index.php
They are there to draw the heat out not suck in fresh cooler air.
You need to add vents under the eaves to get a flow happening.
And they are not going to work on a hot stinking day with no wind.
They do cool the roof space down quicker when the southerlies arrive.
I think you would be best to put in solar vents which can be expensive.
http://solarvent-px.rtrk.com.au/
http://www.solatube.com.au/residential/product-catalog/solar-star-roof-ventilation/index.php
You still need vents in the eaves.
You're talking about the whirlybirds, right?
They would help a little bit.
A light coloured roof would help a bit.
So would Air Cell (or similar) sarking.
And decent insulation.
If you do one of them, you'll possibly notice some difference. Do all four, and you'll notice a greater difference.
I reckon the one that would give the best bang for its buck would be good quality ceiling insulation.
A light coloured roof would help a bit.
So would Air Cell (or similar) sarking.
And decent insulation.
If you do one of them, you'll possibly notice some difference. Do all four, and you'll notice a greater difference.
I reckon the one that would give the best bang for its buck would be good quality ceiling insulation.
air does not come in a whirly bird
savonius rotors of which the whirly is one spin even when made of cut barrels,
a barrel cut vertically and arranged as an S around an axle, spins,
by the difference in pressure between air striking a vane tapered inwards, and a vane tapered outwards
the spin, creates low pressure at the outer edge
(moving air is always at a lower pressure than adjacent stationary or slower air, high school physics, I cant remember why, high school is a long while ago)
the spin and associated low pressure annulus in a whirly, draws air from the plenum, and thence the roof space
on moving vehicles
on roof tops
powering generators
powering water pumps on the stuart highway at the tennant creek telegraph station from ~1930
whirlies create quite significant air movement, but are useless without eave vents to let replacement air in, the total pressure drop created is small, they cant suck through cavities (made toilet paper parachtes for one of the camper's kids here, and launched them out the whirly in the bathroom, steam removal and parachute launcher, not a normal household installation)
whirly(s) at the top
foil sarking sealed to rafters(?, sloping timbers) eave vents in the bottom to make a chimney system with 'hot side' separate from the general roof space, good insulation on the ceiling
savonius rotors of which the whirly is one spin even when made of cut barrels,
a barrel cut vertically and arranged as an S around an axle, spins,
by the difference in pressure between air striking a vane tapered inwards, and a vane tapered outwards
the spin, creates low pressure at the outer edge
(moving air is always at a lower pressure than adjacent stationary or slower air, high school physics, I cant remember why, high school is a long while ago)
the spin and associated low pressure annulus in a whirly, draws air from the plenum, and thence the roof space
on moving vehicles
on roof tops
powering generators
powering water pumps on the stuart highway at the tennant creek telegraph station from ~1930
whirlies create quite significant air movement, but are useless without eave vents to let replacement air in, the total pressure drop created is small, they cant suck through cavities (made toilet paper parachtes for one of the camper's kids here, and launched them out the whirly in the bathroom, steam removal and parachute launcher, not a normal household installation)
whirly(s) at the top
foil sarking sealed to rafters(?, sloping timbers) eave vents in the bottom to make a chimney system with 'hot side' separate from the general roof space, good insulation on the ceiling
sidebar
and there will be a noticeable effect from the whirly(s), it(they) will be only pulling heated air from the much smaller space between roofing and sarking, not from the whole roof cavitythe minimum insulation in other places is R20,
Aus ads for R2.5, as hi-efficiency
crapola, increased insulation saves more than it costs(ppor yay)(ip ppphhhhhht), insulate underfloors, walls, ceilings to as high a number as there is,Aus ads for R2.5, as hi-efficiency
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We had whirly birds fitted around 15-20 years ago. We had two installed close to the high points of our roof.
We also fitted at least 2 fairly large vents to the eaves on each side of the house (8-10 altogether). These were around 10" x 5", plastic mesh to keep out insects. As already said, the vents are essential if you want the whirly birds to work properly. You need a good air circulation so the hot air can be sucked out.
The have worked brilliantly. Winter is not a problem as we live in Brisbane.
Together with a passive solar design house (accident rather than intent), they have been very effective. We always reckoned we did not need insulation, but installed it under the Rudd scheme and found it really did not make any difference. We even had the installers back to check it had been installed correctly.
Marg
We also fitted at least 2 fairly large vents to the eaves on each side of the house (8-10 altogether). These were around 10" x 5", plastic mesh to keep out insects. As already said, the vents are essential if you want the whirly birds to work properly. You need a good air circulation so the hot air can be sucked out.
The have worked brilliantly. Winter is not a problem as we live in Brisbane.
Together with a passive solar design house (accident rather than intent), they have been very effective. We always reckoned we did not need insulation, but installed it under the Rudd scheme and found it really did not make any difference. We even had the installers back to check it had been installed correctly.
Marg
Good insulation should be more effective. Certainly works in my PPOR in Brisbane.
Engineers will discount the whirlybirds as they believe the largest factor in hot climates is radiating heat - i.e. radiating from the roof and directly heating up sections below.
I had a recent 'discussion' with an architect on one our large residential projects at work, and he wanted a black roof. Claimed it didn't significantly affect what was happening below in the units as the largest proportion of heat transfer was - once again - raditaing heat.
I told him to make the roof as light as possible regardless! lol
Engineers will discount the whirlybirds as they believe the largest factor in hot climates is radiating heat - i.e. radiating from the roof and directly heating up sections below.
I had a recent 'discussion' with an architect on one our large residential projects at work, and he wanted a black roof. Claimed it didn't significantly affect what was happening below in the units as the largest proportion of heat transfer was - once again - raditaing heat.
I told him to make the roof as light as possible regardless! lol
