Ceiling fans

For what it's worth, we are off-grid in Texas and we purchased three Nextek Vari-Cyclone DC ceiling fans for cooling (we do not have A/C...just passive solar design with some strategically placed venting windows, no west-facing windows, etc...but that's a whole other story).  Anyway, the Vari-Cyclone ceiling fans are pure DC and are indoor/outdoor rated, which is nice.  We don't have A/C, as I mentioned, so our indoor humidity levels can get somewhat high in the summer, which means that an indoor fan's blades can begin to droop!

We have several 24 volt DC circuits in our place and these fans barely use any power...something around 18 watts on high.  On high they push a fair amount of air, but nowhere near a "blast".  The manufacturer does highly recommend the use of the 12v/24v speed controller for controlling the speed.  Without the speed controller you really only get one speed and no reverse, so it's totally worth it.

In terms of quality/cost...one fan plus one speed controller ran us about $320 total, plus shipping.  We were NOT impressed with the quality of the product when it arrived and was first set up, as all three fans wobble slightly and/or make noise at certain speeds.  We tried fan balancing kits, and various other remedies, and worked with Nextek over several months to solve the problem.  However, the only thing that made a marginal improvement (still some wobble and some slight noise) was making sure the Vari-cyclone fans had four blades instead of three (they sell them in three and four bladed versions...same price).  Nextek's support, however, was great and they did a good job supporting their product. So, mediocre product quality, but great customer service.

Hopefully this helps you out...

I wish I could find the link again, but ideally for best efficiency with minimum noise you really want the largest possible fan you can fit in, no smaller than 56 inches.