Hi All, I have a question regarding the whirlybird (and similar) roof ventilators - i know they can be quite effective in reducing the temperature of the roof cavity space. But does that temperature reduction translate to any significant change on the interior of the house for an insulated roof? Thanks for any comments, Cheers, Scott
g'day scott, it will help if you put vents in the ceilings of the rooms as well, try to put the vents into the appropriate places in the ceilings. also another thing for the main from what i have seen most try to get good results with minimum spinners ie.,. the use 2 where they should use 3. better designed homes will do the job better. len 8)
Roof ventilators Hi Scott, I was involved in performing energy assessments for the Alternative Technology Association (ATA) The assessments involved me going to peoples homes and discussing their energy usage & how to reduce costs etc. One of the things that came up on a fairly regular basis was roof ventilators and their benefits. As a result I did a lot of research on them. After looking on the web for ages I was surprised that I was unable to find any independent report that showed that roof ventilators had positive benefits. I found quite a few that stated that they had no effect/benefit at all and quite a few actually recommended that you don't waste your money on them. The end result was that I no stopped recommending them during assessments.
ventilators Thanks for the info Simon. Given that's the case, that the whirly bird thingmejiggys aren't of much chop, then i suspect in an insulated roof they'd be next to useless. I must admit though, i can think of one example where use of the whirlybirds was effective - i do some volunteer work for an amateur radio astronomy group, and their shed/workshop gets extremely hot during summer. Installing a whirlybird made quite a lot of difference - not only in drawing out the hot air, but also allowing air circulation via the door and window. Of course though, this is an example where the ventilator is drawing hot air directly out of a hot 'room' rather than an enclosed roof cavity sitting above the room. This leads to Len's comments about ventilation holes in the ceiling of rooms being important. Cheers fellas, Scott
I remember a solar installer guy telling me about having grill type vents in the arcatraves (spelling) to allow cooler air to be drawn in from under your over hang.. this then increases air flow in the roof, blah blah blah.. I can't really remember what it was he was drolling about , as it had nothing to do with my question.. But it was something he did satndard in all solar installs, to help insulation..
Nowadays most new houses don't even have eves to help shade the walls...... And the number of houses I've seen recently with black tin or black tiles on the roof.... :shock: So much easier just to turn on the A/C.......
I know, and arent' they shit... I lived in Cottesloe for a while when I was working over there, and all the new houses had no eves and there was no nice big trees for shade or anything. AAHhhh would drive me made.. I don't think I've had aircon for a while.. I've grown no to fuss much about it.. Strip off and walk around in my undies,,, good for the skin, good for the env, probably not so good for the neighbors...
hahaha :lol: :lol: :lol: You just have to be sure to remember that your only wearing your jocks before you answer the door or get the mail etc..... It works... I agree, I don't have A/C, never have.. I have enough mature trees around to keep things reasonable on bad days, and yep, those really bad days, strip off and have a cold drink.... Joel "permaculture naturalist group"
We too have never had air conditioning - when it gets really hot we strip off and lie on the cool tiles inside - it is just lovely - sometimes too cold even :lol: :lol:
Gee id better not mention that we bought a reverse cycle last year..not for me but my wife...shes not as permie as i...spoused to be for those bad days over 50degs summer below 00c in winter.How do u keep warm? Gotta be better then a fire i think ,,,,maybe? how do thers keep warm/cool? Tezza ps I thought wirlythingys could be good but need maybe open shut vnts to allow out of rooms if no ceiling holes isnt hot air supposed to be displaced by cold air from the bottom etc
we keep cool in summer, warm in winter, no roof cavity to worry about all because we have our properly designed home, oriented on the right aspect on our land too easy. think outside the square come outside the comfort zone it works and is efficient. len 8)
Roof Ventilator choices We recently installed an Edmonds Supavent rotary ventilator on our house in Melbourne, to extract hot air from the ceiling cavity in summer. We fitted an optional throat damper to damp the air flow during winter. It is also important to install an eaves grille to allow air to freely enter the roof space. Rotary ventilators are very common on houses in the tropics but not so common in te mperate Melbourne. I have personally got up in the roof cavity of Melbourne houses during February/March and the temperature easily gets up to 50 degrees celcius. Down below people have their aircons blasting because the ceiling is acting like a radiator. There are two main companies in Australia- Edmonds and Condor. See https://www.edmonds.com.au or https://www.condorvent.com.au/comparison.
How do you go about heating that space Anissa? I'd love to see photos of your converted church. Is it stone or timber?
It's timber. Winter wasn't too back this year. We had a woodfire heater which does the trick. This is the only photo I have on the computer at the moment. Not a very good shot!
I love the brooding sky in the picture Anissa! Looks like you are in a lovely piece of the world. Looks like a lovely house - I imagined it on a hill - being an old church. I love the chook dome too
Yeah we are on the top of a hill, but the church hall was relocated 7 years ago and renovated. We get some killer winds here though. Of course it is usually windy the day we want to do some mulching.
This turned out to be a livelier thread than it would appear, all of you nudists! Our house is designed to ventilate naturally, and we have no doors internally, to allow flow of air. All of our privacy gradients are created by changes in elevation opr changes in angle. Our first floor is open to the environment, except the stone part of the house, which is sheltered by big eaves and the rest of the house. It stays cool, and the outside part, also under the house, stays cool too. The trick for the humid lowland tropics is to bea able to harvest breezes, but still be able to close up rapidly in the event of inclimate weather. We seem to have done that, tho the roof has a few itty bitty drips when it pisses. If it gets really hot we go down to the river, which comes out of a spring about a half klick up the valley, so the water is coooooool, and refreshing. And, Anissa, your house looks beautiful in the photo. I especially love the chook dome! Joel, your aquaponics garden :wav: looks like a very cooling addition to your house.
Next month we are getting our (colorbond) roof painted with solar reflective paint. It's supposed to reduce the internal house temperature by up to 8 degrees celsius on hot days. I have checked it out quite thoroughly and we have decided to book a painter to do it. The paint will cost about $800 (for a roof that is about 130 squ m, and the painter (with two guys working for him) another $800, making $1600 for the whole roof. This is what a reverse cycle would cost isn't it? Actually the price of the paint has recently gone up by around 50%, but I am getting it at the old price - I think I am the last buyer to squeeze in. We have no air con - just wall fans which cost about $16 ea at Bunnings and I installed them myself - easy. We do have roof insulation, but as someone said on really hot days that just radiates the heat through, but, worse, it continues to radiate heat till about midnight. Cheers Peter
I believe Peter Clements meant to say https://www.condorvent.com.au Looked at the site and the design is vastly different to the conventional and quite benign in appearance
