We are in the process of getting our house re-shingled (sp?). I know we need some extra type of ventilation up there, but I am unsure as to which type. I had both a 14" whirly-bird (spinny turbine-kind-of-thing) and 3 regular “vents” recomended. I live in a climate where the summers can get 30+ celcius (with a south facing roof) and winters -35 C. I am leaning towards the whirly-bird design, but unsure.
Can anyone tell me the pros/cons between them?
Thanks
Ugh. Please forgive the spelling. 
Those turbine things are undesirable because they allow rainwater in. Box vents are ugly and inefficient.
When I had a new roof put on, I chose ridge vents. They’re very efficient and practically invisible.
I have a turbine thing and never had any problem with water getting in. Im not saying a few drops might not get in but I’ve never had any problem that I noticed. The good thing is the wind makes them rotate and circulate the air out much faster. I guess you can also get an electric fan to do that.
I think a ridge vent is the best but only makes sense if you are building a new roof. For an existing roof, eave and soffit vents with a thermostat-controlled fan makes sense to me but my contractor advised adding “turtle” vents to the eave and soffit vents I already have and that is what I did. It seems to me for where you live where it doesn’t even get really hot (30 degrees C isn’t what I call hot), turtle vents should do the trick (I’m assuming you already have proper eave and soffit vents).
A roofing buddy of mine said that he removes more turbine vents than he installs. According to him, water will get inside the attic when there is a) rain, and b) wind.
I say, check out ridge vents. They’re cool.
well, YMMV. My experience is that no water gets in. I guess maybe it depends on the model. If it is windy and the vent is rotating, it just spins any water off. Maybe you can ask someone who has the same model and see what they say. I can see where some models may be badly designed.
You can ask a roofer or visit a store & check on what they have in stock these days. I can’t see the pitch of your roof or what may or may not influence the drafts around it.
Whatever you use for vents, make sure you have adequate venting in the soffits as well. If the air can’t get in, there’s no use in doing a better job allowing it to get out. I assume this is an unfinished attic, not living space.
You can too put a ridge vent on a finished roof - just take up whatever’s covering the top couple of inches on either side, cut away an inch or so of wood to expose a gap on each side of the ridge beam, and put the vent on. Cover it with pieces of new shingle, or else there are sheet aluminum ones that don’t need covering at all. You don’t have to strip the existing roof any more than that. It will be the most effective venting system, too.