Susan, It's not that a remote fan has to be sized larger than a normal fan. It's that a fan just needs to be properly sized. Period. And if you have to choose between slightly smaller and slightly larger, I'd recommend larger. Small baths are typically sized by the volume of the room. Larger baths can also be sized by the fixtures within that room. Smaller baths can still effectively vent with a single vent. Larger baths can be more effectively vented with more than one vent. You'll find many people look at the volume of the room (say 150 ft) and then specify a 150 cfm fan to give you one air change per hour. However, that fan, while rated at 150cfm, won't move 150 cfm of air due to the resistance of the ducting, the number or bends in the duct, etc. Solid 4" metal duct offers less resistance to air movement than the ribbed flex duct. More bends offer more resistance than straight ducting. These inefficiencies mean that your 150cfm fan is now, in reality, only moving 120cfm, or 100 cfm, or 90cfm. To make up for that added resistance, the fan needs to be upsized. Some of the better manufacturers have always considered basic duct resistance in their calculations. With the Fantech, it's rated at 230 cfm. However, Fantech realizes that the basic static resistance due to basic run of ducting is .4 pull, so the effective volume of air that the fan can move is actually about 195-200 cfm. Add a couple of more bends, or extra feet of straight run, or ribbed flex versus the smother solid wall duct, and you can get up to .6, then you're only getting about 170 cfm of real air movement. Nutone? If I needed a fan for a powder room, I might be persuaded. But for good quiet ventilation, Panny's are good, they're quiet too. For larger volumes of air and with only using a single fan, Fantech remotes are better, and quieter. Do realize that it's sometimes tough to spend extra money on ventilation. Until you realize that your existing fan can be so loud that you prefer to not use it. Then you can end up with air problems, excess moisture, mildew, etc. And the expense of replacing a fan is tough to swallow. The Fantech 230-3 is about $180-200, that's for the fan and the two vent asemblies. For remote fans, Panasonic does have the FV-20NLF1, it's comparable to the Fantech 230 in regards to how much air it moves. It's a 240cfm with no load, which means it should be around 200cfm at .4, and cost wise it's probably around $130-$150 for the fan, then you'd need the two grids to go in your ceiling. Total cost for the fan and two grids might be slightly more expensive than the Fantech, which includes everything. But I do have to say that when it comes to large fans, I'm more familiar with Fantech than Panny. Conclusion? Either the Fantch 230-2 or the Panny 20NLF1 will, even when "derated", move enough air to vent your bathroom using two ceiling vents. Both are remote, so they will both be quiet if properly installed. If you decide to go with two individual, fully contained ceiling vents, each with their own fan, then make sure they are properly sized for the mount of ducting they will have to push the air through. Size the one in the shower for the size of the shower. Size the one in the bath for the size of the bath. I've never had to replace a Fantech for being noisy. I've replaced a couple of Panny's for noise, but never a "whisper" series, although I did have to redo the ducting of a Panny whisper because the installer had a coupe of bends that mad too much air noise. After I tweaked things it ran quieter. I've replaced several Nutones due to noise. All my opinion. Your mileage may vary. Mongo

Thanks. Perhaps it's a typo in the advertising and the airflow efficiency is 84, but I will follow up with the company to double check. If that's the case, however, is fan V still more efficient? Also, if it helps, fan A has a "premium power 188x25 mm torque-induction motor," and fan V has a "premium power 165x25 mm dc motor."

True, you do not want to cover recessed lighting with fan blades unless you like the strobe effect. In some ways I'd prefer two fans as it will cover more than one, and give the option of running just one. Let's remember that fans don't actually 'cool' a room, they move air around, and make us feel cooler from evaporation (I've seen people switch on a fan and leave the room for it to 'cool down' lol) Keep in mind the option of some sort of roof vent and/or ventilating skylight, that would be very effective in the evening.

40s & 50s attic fans resembled a modern ceiling fan but were belt driven. Similar fans are still used in livestock barns,construction sites and commercial warehouses. They are whisper quit if mounted so that viberation isn't transferred to structural framing.