It is always disappointing when you have high hopes for a product, and they just completely fail your expectations.
I had that recently with a portable HVAC unit.
Sometimes in the summertime my bedroom can become really hot. I don’t know why it is, but my bedroom is always the warmest in the entire house. Naturally, this can make it hard to sleep sometimes. Even though my central HVAC runs perfectly fine, it never seems like my room is cool enough. So, I decided the best solution would be to get a portable HVAC system to support the main central air conditioner. This way I can get proper sleep. I went and bought the portable air conditioning system from a local HVAC store, and for the first week, it worked beautifully. Every single night that I had that portable air conditioner running, I slept for hours. I never realized how much sleep I was losing thanks to temperature. Everything was going well, until it suddenly wasn’t. A little over a week later, I wake up in the middle of the night and my room is back to feeling overheated. I was confused, did I forget to turn the portable cooling unit on? I had a clear memory of turning it on. I went and checked on it, and it was off, but I couldn’t get it to turn on again. I ended up returning the portable HVAC because of this, and then bought another one. Thankfully I didn’t have any additional issues.