Okay, so I finally installed the ControlTemp CT72 in my rental property after hearing mixed reviews. Here's my honest take:

First off, installation was a breeze - if you've swapped thermostats before, this is basically plug-and-play. Took me under 15 minutes while sipping my morning coffee.

The tamper-proof feature works EXACTLY as advertised. Tenants can't crank the heat past 72°F or AC below 72°F. My oil bill dropped noticeably within the first month - goodbye $500 heating bills from tenants who think we're running a sauna!

BUT... there's a catch some reviews don't mention. Unlike what I hoped, tenants CAN see they're being limited. The display physically won't go above 72°F, so they know immediately something's up. Would've been genius if it showed higher temps while secretly capping at 72°F.

One major warning: Had a scary moment when mine malfunctioned and kept heating non-stop to 88°F! Luckily caught it before damage was done, but that was NOT fun getting that emergency call from my tenant.

Final verdict? Great for stopping temperature abuse, but not as discreet as I'd like. And watch out for potential malfunctions - maybe install a secondary cutoff just in case.