One of the projects that has been on my list to fix at our house for years has been our downstairs bathroom fan. The bathroom isn’t frequently used, but when someone showers it sounded like a 747 taking off. It probably won’t surprise you that it also wasn’t effective at pulling moisture out.
The old fan was 8 inches by 8.25 inches which is still a standard size. The problem is that the hose was located directly above where the fan housing sits which means there isn’t a lot of room in the ceiling for a new fan. Most bathroom fan housings are around 5 inches deep, but these models wouldn’t work. It seems as though these thinner bathroom fans were common in the 80’s when our house was built. Based on how the fan was installed and how much of a pain it was to remove I am assuming it was original. After 37 years of use I think it’s time for a new one.

After several frustrating trips to the store I finally found the Delta Breez Slim models. Specifically, I bought this Delta Breez SLM70 Slim 70 CFM Exhaust Fan
from Amazon. It set me back only $38 which I thought was very reasonable. Bathroom fans are measured by the amount of air flow measured in CFM (Cubic Feet per Minute) and sound. My preference is to always buy the highest CFM model with no regard to the level of sound. Now 70 CFM is around the middle of the range, but this is the only model that would fit in my existing hole. I didn’t want to go through the hassle of cutting a wider hole.
Note that they offer similar models in both 80 and 100 CFM options, but they have different housing dimensions and support a 4 inch duct, but come with a 4 inch to 3 inch adapter. Not surprisingly, if you go with a higher CFM model, but use a 3 inch duct you lose some of air flow the fan might otherwise be able to pull with the 4 inch duct. Also worth noting is that the 70 CFM model is rated at a sound level of 2.0 sones whereas the 80 and 100 CFM models are rated at 0.6 and 1 sones respectively.
The housing dimensions for the 70 CFM model are 7.5 x 7.2 x 3.9 inches which meant there would be a small amount of space around the new fan (my hole was 8 x 8.25 inches). My project started with taping up the existing holes in the hose. Apparently some squirrels thought the hose was a good place to hide small acorns. I quickly realized there was no proper vent on the outside of the house meaning squirrels were free to enter the hose and nibble? on my hose. One project sometimes leads to the next…
Once the hose was repaired, I turned off the power and began hooking up the electric. This was pretty easy, especially if you have experience installing a light fixture. There was a small metal piece that needs to be removed to access the electric. Once hooked up you simply reattach the metal piece, thus hiding the wires and wire nuts inside. The next step was to attach the hose which I then sealed with the same aluminum (foil) tape. Having the extra space made it very easy to work with the fan housing. Next, I used three nails to attach the housing to the joists. I was lucky that the location of the air duct, electric and the side that it attaches to the joist were all the same as my old fan. Note that you first install the housing and then screw the actual fan in later.
The below picture was taken with the housing still intact, but there are three screws to remove the fan which are then used to reinstall it once the housing is in place. The fan has a plug which attaches near the electric box.
The fan grille was not quite big enough for my hole so I had to make some adjustments so it covered up the gap. I then tested the fan and it successfully held up a piece of paper. Note that this model also has a green indicator light when the fan is turned on, but it isn’t necessary since you can definitely hear it when it is turned on.
Overall I am happy with the Delta Breez SLM70 Slim bathroom fan. I think for the money you can’t go wrong. Bathroom fans vary quite a lot in price and this seems like a good quality fan for under $40. The install was surprisingly easy and the included directions were helpful. The fan isn’t as quiet as the larger fan models or those marketed as quieter, but doesn’t bother me or my family. While it is hard to gauge volume from a video you can get a sense of what you might expect in the quick video I made below. If you’re not going to buy this specific model due to your needs you may still want to consider Delta fans. They were carried at my local hardware store but Amazon also stocks several of the models. I will continue to update this review with how the fan is performing over time.
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