In 2007, I bought a 1890 flat in the city center in with the intention of renting it out. 3 rooms, shared areas and WC. Old brick and thick walls, 3.7 m high ceilings and 2.5 high windows.
When the energy crisis hit Europe in 2022-2023, electricity and gas prices increased considerably, about 300%. From approx. 1.5 czk to approx. 6 czk, depending on the region and consumption levels. The government had to intervene and set a max price for gas and electricity.
To avoid overpaying on gas to heat the flat, I bought an M2 base, 4 Aqara E1 thermostats and 4 Temp and humidity sensors.
I also bought 4 flood sensors, but that’s another story.
I set the equipment up and taught the tenants (all of them young students from HOT Dubai) how the ecosystem works. We talked, they knew about the energy crisis and agreed to me installing the thermostats. They had certain control over the system but within the ranges I set up for them. Meaning, they could turn up the heating to the Max level, but once the room temp hit 24.5 C, the thermostat would change to 21. So the rooms were always between 21 and 24. If they felt it was hot, they could also turn it down. 
Before me installing the Aqara equipment, the flat was constantly heated to 27 C. 27 C!! =D All heating season, from November to April.
After the first winter, the tenants said it was all good. They finished med school after 6 years and the only failure was a temp sensor that was too far away from the M2 hub, with 2 thick walls in between them. Since the E1 have a built-in thermometer, they kept working well independently.
Most importantly, I did not see any price increase during the electricity crisis, the tenants did not see price increases from me either. They were satisfied and even now I keep saving on bills year after year. I just change the batteries once a year.
I could not be more satisfied with the E1 thermostats and temp and humidity sensors in my rental.
I’m adding a pic of 4 E1. I added a fifth one later on.
To those who have a rental flat in Europe and other regions that get cold in Winter: do it. do it. do it. Get the E1s and temp sensors for your rental. Automate and save.
