I need a new bathroom exhaust fan

The exhaust fan in the guest bathroom hasn’t really worked well ever since we bought the house a couple of years ago. It makes a horrible noise and I’m honestly not even sure if the fan actually turns. My toddler is starting to potty train and he accidentally turned the fan on last week and the noise scared him. Now he’s to scared to go to the bathroom if the light is off because he doesn’t want to accidentally turn the fan on. For now, I’ve disconnected the switch and capped off the wire. I want to replace it before it starts getting to hot to work in the attic.

Since I have a Sense, I’m naturally concerned about saving energy. So even though I’m sure a bathroom exhaust fan doesn’t turn on very often or consume a ton of power, I know it’s something that will be used consistently for many years. I’ve just been casually browsing the web and I see some that claim to use only 6.5W and some that use up to 100W. That’s a big difference.

So I’m wondering if anyone has any feedback about their exhaust fans in regards to

  1. How much power does yours use?
  2. Has it/they been detected by Sense?

According to what I’ve read online, to be effective it should be able to exhaust the whole room’s worth of air 8 time in an hour. For this room, that comes out to 52 CFM. There are other factors I’m taking into consideration as well. Things like how loud is it? Does it have any other features?

Also… I know pretty much nothing about motors. What should I look for? What should I avoid?

California Title 24 puts a couple of low energy requirements on any new bathroom fans installed. I’m guessing you can find compliant fans throughout the US. Most employ LED lighting as well.

  1. Fans shall be ENERGY STAR® compliant and be ducted to terminate outside the building.
  2. Unless functioning as a component of a whole house ventilation system, fans must be controlled by a humidistat which shall be readily accessible. Humidistat controls shall be capable of adjustment between a relative humidity range of 50 to 80 percent.

Replacing bathroom exhaust fans can be fun! You have already overcome the first hurdle in understanding how much air you need to move (52 CFM). With air movement, more isn’t necessarily always better. I’ll explain.

I have had a few friends that have pulled out one exhaust fan, and opted to install one of a much higher capacity (pulled out a 50-ish CFM fan, and put in a 110cfm). In today’s energy efficient and air-tight homes, this can cause a negative air pressure in your bathroom, pulling drafts, causing doors to move/jar, etc.

If you are concerned with the loudness of the fan you’re looking at, check the package for a rating in “sonnes” - this is a measure of the noise made by the fan. As @kevin1 pointed out, it’s always a great idea to watch for the energy star symbol when shopping.

As you asked, my Broan bathroom fan uses 28W of energy when activated. It is controlled by an electronic humidity control, and has not been identified by my Sense yet…

Yeah, I’ve noticed this. I will need to research what this means. I’ve never heard of loudness being measured by anything other than dB.

I replaced all my original builder grade bathroom exhaust fans with Panasonic fans. They use 23 watts when running. Mine are also on a timer now too as my wife would always leave them running.

So far everyone that has chimed in on the places I’ve posted about this say to go with Panasonic, so will definitely look into them.

That’s what I found when I was researching replacements. We have four of them and love them.

Look at the Panasonic DC fans with multiple speeds … with adjustable settings you can comply-with or outperform Energy Code requirements. Houses are often unpredictable so the ability to switch things after the fact is very handy.

There are models with a motion and humidity sensor and adjustable humidity settings and timer.

One option, if you want to integrate things with other ventilation (vent hoods; ERV; fresh air intake), would be to get a single-speed fan adequate to code and then modulate it (switch it on/off) using a smart plug via Sense. I’m doing this in a crude way with my vent hood and bathroom fan via Sense and IFTTT. It’s more of a “proof-of-concept” than practical. I’m waiting to install an ERV before working out the details.

Consider insulated piping & exit thru attic wall, not soffit which can let humid air back into attic. Check utilities for free home efficiency audit, which can include nearly free work of this type. Blower door test included.
The new fan I installed is on a mechanical timer & quiet but unrecognized by Sense. Another fan is recognized; not sure if that matters to you.

I will also agree that Panasonic’s “whisper” series is the way to go. Low wattage, rated for continuous use, quiet, and some even have static pressure sensors to ramp up the fan power to overcome crappy ductwork installations.

Or just pull numbers off the motor and replace the motor instead of the whole fan. Avoid the attic and potential drywall/ceiling issue. The few minutes a day it’s on isn’t a huge deal.

I just replaced a bathroom fan I had, which contained a Fasco motor. See pages 19-20 of this PDF: http://www.koffler.com/pdf/Fasco_Full_Catalog.pdf. I matched up the motor and ordered one off of Amazon.

I installed one of these BreezSignature VFB25AEH – 130 CFM with Humidity Sensor. If you were to run it 24/7/365, at $.10 per kWh, it would cost less than $20/yr to operate.

I have it outside my shower door. It senses the humidity from the shower and turns on automatically. When the humidity returns to normal, it turns off. You can also flip the wall switch off then on and it’ll turn on until flipped off. Flip back to on and it’s humidity sensing again.