There is a bit of comment regarding different versions of roof ventilation in the following topic that may help
The following I can recommend (particularly the roof and ceiling insulation rather than just the ceiling):
Getting insulation will make a big difference to your comfort, have you thought about splitting the insulation (2.5 and/or 2.0 batts) to put batts on the roof underside and on the ceiling, this may provide both noise reduction and reduction of cavity heat.
I have no recommendation either for or against about the following but it does show options regarding thermostat control and after dark operation. I am sure there would be similar in most brands
We did look at the Solar Whiz units on our previous house (whirlybirds were getting old) but have just moved into a new home and have split the insulation, and are awaiting summer to see if we need venting here or not. We do have ducted AC so we way up cost of the heat load and performance. If the cavity load isn’t too high we may not worry.
Motorised devices and motors make noise. The specific noise any motor makes may or may not be objectionable to any particular individual, based on frequency and volume. The fan and resultant air motion will add to it. What bothers one may not be a worry to another, so take input accordingly. If your 4.5R insulation will be on your ceiling, not attached to the roofing/sarking it should dampen the noise.
Basic solar fans run when the sun shines. They generally have options (priced) to add thermostatic controls but looking at the documentation from Bradford it appears yours does not have that as an optional package, but adding one should not be difficult and could solve your problem.
If you have or are about to install a PV system you don’t need a solar powered fan since your PV system will run it, you just need to have a power point added for the fan.
Whether or not you go with another solar powered unit be sure your quotes include a thermostatic control so it only runs when the ceiling cavity gets hot, and an on/off switch remote to the fan placed so you can reach it.
In your place I would first install the insulation and assess the noise. If the noise was treated I would investigate adding a thermostat ; the insertion of an on/off switch and thermostat should be easy even if Bradford does not reference them as options or provide a kit.
For piece of mind you might contact Bradford to ask, and I presume adding them affects your warranty, another issue.
Some homes have exhaust fans/vents that push air (humidity if from a bathroom, or smells from a kitchen or toilet) into the ceiling cavity so consider what might be circulating in the ceiling; others have ductwork to the outside. Whether that matters in your case? If it does you may be better placed for a fan (or whirlybird) to run all year to avoid damp in winter, potential mould, or less likely odours, even when it seems contrary to good heating/cooling practices.
Yep thanks. I found that thread and read through it. It was more about the different classes (mainly powered vs. “traditional”), but no specific brand and model recommendations.
I intend to ask the insulation people whether it’s possible to insulate right under the sarking, in addition to the ceiling insulation I already plan to do.
But I’d still need some ventilation in the roof because:
Even if it’s possible to put insulation under the tiles, it’ll be a very difficult job in some parts of my roof.
Still need to let air circulate in the cavity to prevent accumulation of moisture.
The vibration noise could be coming from the roof rather than the motor per say. If the fan has a slight imbalance (which most fans do), this imbalance can turn into a vibration when it is transmitted through a surface like a roof. If this is the case, it might be worth asking the installer if there is a rubber mount for the solar fan which can be installed or whether it is possible to place reasonable thickness silicone bead/rubber bushes between the fan casing and roof to try and minimise the vibration through the roof.
If it is fan noise (noise of the blades moving through air, it might be possible to install some acoustic sheeting under the roof beneath the fan…providing that there is sufficient space to allow air to readily move between the acoustic sheeting and roof. It would also be ideal to ensure that there is some acoustic absorbent sheeting also installed on the rood side to prevent sound bouncing off the roof bypassing the acoustic board. The acoustic sheeting also needs to be mounted in a way such that it doesn’t become a sound board…a surface which fan vibrations are not transmitted through. This can be achieved using rubber bushes on mounts to the roo trusses etc.
All fans produce noise, so installing another may not solve the problem unless the replacement fan is better balanced/produces less noise at the frequency which you find annoying. This may be difficult to now until after a replacement is installed…and you might find it hasn’t solved the problem.
You hit the nail on the head about my situation, so I’ll fill in on the missing info:
I just had solar PV installed on the roof so indeed the vent would probably mostly run on solar except times when there isn’t enough for all the power use in the house. I assume that’s not quiet a consideration since the fan doesn’t take much power?
I do have power access inside the roof but having a self-contained solar unit should avoid running an extra power cable connected to my home circuit close to a hole in the roof.
I recently also put ducts on the replaced bathroom vents to take the air out instead of into the roof cavity.
I’ll take your advice to check options to add thermostat to the existing fan and perhaps wait for the ceiling insulation to be in place. Maybe it’ll save me some money on complete replacement.
I took a video of the fan and to my unprofessional ears it sounded like it’s coming from the fan itself.
It seems that this is the first time this roofer installs a solar vent so not sure if he’s aware of all the options and considerations. (he looked experienced and professional on other stuff he fixed on the roof)
They don’t use much power. If you just ‘plug it in’ when the PV is generating it is generating and supplying as much as it can, but when it isn’t (cloud cover) the fan will be running off mains and still cool/moving air when it gets hot in the ceiling. If it runs only on its own solar it might be stopping on hot, humid, overcast days when it is needed. So many tradeoffs
If it is a humming or whirring type noise, it could to be a vibration If it is a blowing, propeller or whistling type sound, it is most likely the fan.
It is worth noting that one of the product guides states:
Avoid positioning SolarXVent over bedrooms, bedroom ensuites or on a roof area adjacent to, or overlooked by an upper level storey of the home where the fan noise may be heard.
I expect that this would be standard advice for any extractor type fan…but they seem to acknowledge that the fan isn’t silent.
Ask if a unit has been sound tested and has a ‘sound power level’ (SPL). Use the SPL if they exist and if noise is the overriding criterion. The lower the SPL the less noise they should produce (assuming they all produce similar sounds/frequencies).
Another thought is if you have too few under eave vents, this may create fan noise as it tries to pull air where supply is restricted. You need at least 4 under eave vents around the house to get the best airflow and they need to be in places so the flow in the cavity is evenly pulled from each as much as possible (to create even temps in the cavity).
As to brands we have looked seriously at the Solar Whiz, there are others eg Solatube. As we haven’t actually used them I can’t say who is best or not. CSR Bradford however should be a very decent provider and you should perhaps advise of your concerns and see if they can offer solutions.
I think the standard that applies to testing certification is ISO 5801 but I could be wrong, there are associated standards with that of which one at least is about sound levels. For embers from fires there are grills that meet AS3959-2009, if you need a grill it should be compliant at least with this standard. Noting that the 2018 version has been released but this incorporates 2 amendments which may not impact grill design.
Thanks. I haven’t searched for all of them but saw a few under eve vents. The roof is not airtight. There are also a couple of tears in the sarking here and there. I’ll check with Bradford about the existing fan.
Moisture management is critical in roof spaces. Airtight can create serious problems. Using a major recognised roofing insulation supplier the expectation would be for reliable advice. IE advice specific to the differences in design of a building and roof. Condensation problems in the roof space can result from inappropriate combinations of insulation and ventilation. The type of roof construction and climate zone also need to be considered. Solutions vary.
An assessment particular to homes in colder parts of Australia, courtesy of the Tasmanian Govt.
Note that metal roofs in particular encourage condensation. Effective ventilation of the roof spaces is a central recommendation.
The under roof sparking and insulation requirements vary with region.
We installed roof vents on our ridgecaps. No moving parts. No noise. Passive venting of hot air from the roof space. Many (probably close to 30) years ago my parents had something called “Cool Caps” installed on their roof. No electricity involved. Vents opened when a certain temp was reached. I cannot find any reference to them online. Maybe some “old-timer” will remember them. I believe that a contained temperature-sensitive substance expanding/contracting or melting/solidifying triggered their opening and closing.
I had two solar whiz motorised extractor fans fitted just under three years ago. Two of the medium sized (RAF900) fans because our house is basically U shaped. The thermostat is set to activate the fans above 26 C degrees and because of the long hot summer nights we have from time to time, I had both units wired to the mains power so if it’s hot enough the fans keep going when the sun goes down.
One of the fans is directly above our bedroom and I can just hear a low hum if I really concentrate. The other is above our living room and I’ve never been able to hear it. The ceiling has polyester insulation but nothing special.
