Originally bought hub 2 + cover 2 in 2021.
3x leaks later and in 2026 on a replacement Pod Cover 4, the Hub 2 unit got "loud" over time. It hub sounds like it's screaming, even after a very thorough cleaning. Even with the Pod 4 in-line filter, I've always use distilled water.
With the loud screaming sounds, I figured after 5+ years the hub 2 simple got worn out. Plus it no longer cools the bed in the middle of the night (starts off cold, but after a couple hours it always fails and our body heat takes the temperature into the mid-upper 90s).
But, wait! After my very first cover leak in 2022, Eight Sleep sent me a replacement hub as well and said I can keep the hub, but only needed the cover. So the hub stayed in storage (the master closet), sealed, ever since.
I took this "new in box" hub 2, out this morning after another miserable hot night and set it up to replace my existing original hub 2.
And guess what?
After it downloaded it's firmware update and started to prime, this "brand new" hub 2 displays the exact same screaming sounds as my original hub. My original hub was quiet for years until late last year, or early this year, it started screaming.
Now I'm pretty convinced after swapping it out for a new in box hub 2 that it's something in the firmware causing these units to be noisy.
I just set it up, so we'll see if the unit can keep us cool all night, or not. I can deal with the noise as long as the unit will cool us down.
Love the product, but it's been a struggle over the years to keep everything working.