do solar extractor roof fans do anything

[ajm]

new house is very hot. its insulated but still seems hot. was thinking whirlybirds but saw solar extractor fans while doing the search. any opinions? good brands? bad brands? Price per unit, etc.

a couple of other questions:
what do people do to increase the efficiency of insulation?
how are flat roofs insulated?

[rambunctious]

New house as in new to you or new construction ?
You say it is insulated, how do you know
Is the roof colorbond dark or light, or zincalume/galvanised and how old ?
What are the external walls ?
You cannot increase the efficiency of insulation, it is usually good to have depending what it is.

Flat roof would usually be insulated with wool and sisalation blanket directly under the sheeting on top of the battens.
The question you have to ask is, what is the ambient temperature when it is hot because houses can be hot if the temp is above say 27 degrees.

eg here on the sunny coast there were a couple of days last week that were warm.
If we feel a little hot under the collar we have a ceiling fan in every room.
At night for the past few nights we have used the bedroom ceiling fan until it cools down early morning and one of us turns it off.
We also have 2 aircons, 1 in dining/ lounge and 1 in main bedroom but only ever use them for reverse in winter.
If??? they are turned on to cold in summer it would only be for half an hour to lend a little cool to the rooms.

edit...In relation to whirlys, yes they do work to remove heat from the ceiling but nothing beats keeping the heat out with insulation to start with.
As to solar extractors I would have to say they would work also (never had anything to do with them) but of course once any solar setup gets old they will break down also due to the fan having a collector and moving parts (fan)
Fitting either on a flat roof must be done correctly to avoid leaks.

[ajm]

new to us. 2 year old zincalume colourbond roof and roofspace is insulated with pink batts. its an old miners cottage that has been extended and then clad in bagged blueboard. we get a breeze but want better heat deflection. we do the same as you regarding the ceiling fans. hmm, m ight stick with the age old whirly birds on the peaked part of the roof. cheers rambunctious (we're now at Marcoola).