Best smart thermostat for apartments without central AC?

The real issue here is that most smart thermostats assume you've got a central system to work with, so apartments without that setup are kind of stuck. But there's actually a workaround that doesn't get mentioned much: if you've got window units or a portable AC, you can use a smart plug with temperature sensors instead of a thermostat. Plug your AC unit into something like a Wyze Smart Plug or Kasa, then pair it with a separate temperature sensor (even a cheap wireless one). Set up automation so when the temp hits your target, the plug cuts power to the unit, and when it drops, it switches back on. It's not elegant, but it works and costs way less than buying a "smart thermostat" that won't actually connect to anything in your apartment.

If you're in a place with individual wall-mounted split systems or mini-splits, that's different - those can sometimes work with smart controllers, but honestly you'd need to check if your landlord even allows you to swap anything out. Most apartments don't. The plug-and-temperature-sensor setup sidesteps all that because you're not modifying anything, just adding a power controller.

One other thing: some people use their phone or a tablet running Home Assistant or similar software as a pseudo-control system. Not everyone's cup of tea, but if you're already into that kind of setup, it gives you way more flexibility than waiting for a thermostat that'll never fit your situation anyway.

Smart thermostats that work without central AC basically don't exist as standalone products - they're all designed around traditional HVAC systems. The workaround most people actually use is pairing a smart plug with a window unit or portable AC, then controlling it through automation apps. It's not elegant, but it gets the job done.

If you're in a rental and can't modify anything, a smart plug in front of your AC unit is genuinely your best bet. Plug the unit's power cord into something like a Kasa Smart Plug, then you can schedule it to turn on before you get home or control it remotely. You lose the temperature-sensing features of an actual thermostat, but you gain remote control and scheduling. Some people also use motion sensors paired with the plug to trigger cooling when they're home, which saves energy if you're in and out a lot.

The other option if you've got a split system (wall-mounted indoor unit with outdoor compressor) is checking whether your specific model has a compatible smart controller. LG and Daikin units sometimes have their own app integration, so it's worth checking your AC's manual or manufacturer site. But for standard window units? Smart plug is the move. Way cheaper than trying to jury-rig something fancier, and it actually works in practice.

Don't waste money on a traditional smart thermostat expecting it to control window units or portable AC - they're built for central systems and honestly won't do much for you! What actually works is pairing a smart plug or IR blaster (like a Broadlink or similar device) with your existing AC unit's remote, which lets you automate on/off and temperature settings through an app. The folks above aren't wrong about the limitation, but they're glossing over the fact that this plug-and-blaster method is genuinely reliable and way cheaper than any "apartment solution" thermostat you'll find. Set it up right and you get scheduling and remote control without needing your landlord's permission to install anything.