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solar roof extractor

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  1. #1
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    Default solar roof extractor

    Hi,

    Not sure if this has been discussed previously. I'm considering putting in a solar roof extractor system to remove hot air from the roof. I was told that whirlybirds do not too much and relies on the wind. I'm thinking whether an active system will be better. Something similar to this https://www.solarking.net.au/

    Anyone have any experience with them? Love to hear your feedback and/or reviews.


  2. #2
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    I have a gable roof with simple 'passive' vents. Until recently I didn't think they did that much, but when needing to paint directly in front on them, even on a cool but sunny day there was heat flooding out of them. Story short, I see no need for powered vents

  3. #3
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    You position passive vents high up on the roofline, hot air rises meaning that it escapes regardless of the wind. It is evidenced by the fact that they will turn by themselves on hot days without wind. Wind will result in additional vacuum increasing their efficiency.

    When you compare the CFM of solar ones to passive vents, if the passive vent doesn't give you the result you want, the solar one won't either.

  4. #4
    2K Club Member toooldforthis's Avatar
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    Quote Originally Posted by r3nov8or View Post
    I have a gable roof with simple 'passive' vents. Until recently I didn't think they did that much, but when needing to paint directly in front on them, even on a cool but sunny day there was heat flooding out of them. Story short, I see no need for powered vents
    I put them in a weatherboard house ages ago and they worked a treat.
    I often hear the whirlbirds don't do much.
    Thinking aloud ... apparently crossflow ventilation in a house works best when the intake window is open more than the outtake window, so I am wondering if the problem with these whirlbirds is they are not creating enough airflow cause where are they sucking air in from/how?

  5. #5
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    Quote Originally Posted by toooldforthis View Post
    I put them in a weatherboard house ages ago and they worked a treat.
    I often hear the whirlbirds don't do much.
    Thinking aloud ... apparently crossflow ventilation in a house works best when the intake window is open more than the outtake window, so I am wondering if the problem with these whirlbirds is they are not creating enough airflow cause where are they sucking air in from/how?

    The correct install of any roof space ventilation also requires installation of entry ducts, the normal location of these is in the eaves and should be equal to or larger in cross section area that the roof vents.
    https://www.roofventilationblog.com....ntilation/197/

  6. #6
    Je pense, donc METRIX's Avatar
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    I put one of these Solar things in the last house, you need to have air coming into the roof space via under eave vents for them to be effective.
    Same as wirlybirds, if there is no cooler air coming into the cavity then the hot air just sits there, if cooler air can get in the hot air will rise quicker, if you have a forced sucker fan it will remove the hotter air.

    These solar fans do work, if you don't have sarking I wouldn't bother as you need to seal the intake part of the solar fan to the sarking so it's forced to suck air from inside the cavity.
    The problem with sarking is when the roof cavity does get hot, the air cannot escape easily, where a roof with no sarking the air will leak out the tiles, but a roof with no sarking will get a lot hotter than one with sarking.

    I will be putting one in this house, as the roof cavity does still get quite warm (dark tiles) and sarking, overall this house stays quite cool even on the hottest days aircon only needs to come on if it's been really hot day.
    So if I can get the hot air out of the roof then I think it will be fine.
    Mieux vaut prévenir que guérir

  7. #7
    Je pense, donc METRIX's Avatar
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    Quote Originally Posted by droog View Post
    The correct install of any roof space ventilation also requires installation of entry ducts, the normal location of these is in the eaves and should be equal to or larger in cross section area that the roof vents.
    https://www.roofventilationblog.com....ntilation/197/

    I love the way this guy grinds the holes in the eaves with no PPE !!!!

    Even if it's not asbestos eaves it still contains Silicate, which is just as deadly as Asbestos, this is a great video to show how NOT to install the vents.
    Mieux vaut prévenir que guérir

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    Quote Originally Posted by METRIX View Post
    I love the way this guy grinds the holes in the eaves with no PPE !!!!

    Even if it's not asbestos eaves it still contains Silicate, which is just as deadly as Asbestos, this is a great video to show how NOT to install the vents.

    Come on, I swear he was holding his breath while he was cutting. ��

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