Any solar users in SoCal also using a whole house fan?

[russ]

Friends and family have them. Pros: quiet, easy installation, flexible in terms of where you can install them. Cons: more expensive compared to other alternatives.

In my previous house I installed one from Home Depot (~$300 and some elbow grease). Worked great. In my current home I hired a company to install one (small attic so I left it to the pros). They use a 6 blade model that apparently cuts down on the noise. Nice unit. Paid $1,699 installed.

Fan tip speed is where the noise comes from - low tip speed is what you want

[sdold]

Fan tip speed is where the noise comes from - low tip speed is what you want

I've noticed this, the slower fans with the big blades seem much quieter. These are usually belt-driven. Do you think they need to use faster-turning fans with direct drive because the motors need to turn at a higher speed?

[silversaver]

any installer/system in Socal area/Orange County? Pm me.

[bcroe]

I've noticed this, the slower fans with the big blades seem much quieter. These are usually belt-driven. Do you think they need to use faster-turning fans with direct drive because the motors need to turn at a higher speed?

That is pretty much how it is, bigger & slower is quieter. Becomes obvious if you design enough
electronic equipment. Variable speed fans help a lot. Work to reduce fan noise includes that
uneven spacing of my car radiator fan blades, spiral center supports, and interesting asymmetric
blade shapes. The centrifugal fan in your furnace is generally a quieter design than an axial flow.
I built quite a few speed controlled fan systems. Bruce Roe

[J.P.M.]

I've noticed this, the slower fans with the big blades seem much quieter. These are usually belt-driven. Do you think they need to use faster-turning fans with direct drive because the motors need to turn at a higher speed?

Partly, but mostly its a cost thing. Obviously, direct drives don't have the belt/gear/etc. losses and thus have lower power requirements = smaller motors & lower op. costs. Lower speeds need large dia./areas for same vol. of air movement. Lower speed -> less noise, but bigger fan area, more mechanical losses and higher mfg./maint. cost. Quieter operation is sure nice but it's the no free lunch thing.

[SunEagle]

Partly, but mostly its a cost thing. Obviously, direct drives don't have the belt/gear/etc. losses and thus have lower power requirements = smaller motors & lower op. costs. Lower speeds need large dia./areas for same vol. of air movement. Lower speed -> less noise, but bigger fan area, more mechanical losses and higher mfg./maint. cost. Quieter operation is sure nice but it's the no free lunch thing.

A bigger and slower "fan" seems to be the direction the large wind turbine are going. The original ones were in the 100 kW size. Now they are taller and about 3 MegaWatts.

[TypeRx]

any installer/system in Socal area/Orange County? Pm me.

Look at my original post in this thread. I purchased my fan locally (south orange county) and installed it this weekend myself. They will install for you if you want. I am mildly handy (at best). Works great..looking forward to see how well it performs as the heat rolls in this week.