Water Leaks, Power Measurement and Temperature.
The task of monitoring for water leaks, temperature and measuring power is best served by some remote tools available on the market.
Most tools rely on Wi-Fi, zigbee, 433mHz etc., signals to communicate through the internet connection remotely to your phone.
This in itself is a weakness as if your wi-fi is not working then most of these tools fail. But if the wi-fi or ethernet connection does not fail then these tools are of value.
Lets look at some of these tools that I feel are worth considering.
The lowest cost unit is the Sonoff suite of products. The list is comprehensive and the cost is low. For example the wi-fi / 433Mhz central hub for these devices costs less than €9.00 and as an example the water leak sensors are approximately €8 each and it uses a lithium battery for reliability (needs to be purchased separately).
The product is very well made and a certain level of IT skill is involved in setting these up. It operates at a very safe radio frequency like that of your car remote control rather than higher frequency’s but the hub uses wifi so if one keeps it close to your router and keep the router as faraway as possible from you it is probably the best approach.
I would advise that a separate sensor unit (regardless of which product you select) is installed in a location that you can easily check to ensure that the system is functioning correctly as water leak sensors can end up in locations that are difficult to inspect and check such as behind dishwashers etc. One needs to change the battery every year or two on each of the sensors or when your test unit fails.
Next on the list is the Samsung smarthings hub and sensors https://shop.samsung.com/ie/28020607-smartthings
This type of device links to other well know products such as Amazon Alexa and costs around €90. They also provide water leak sensors to connect to the above. This will be easiest to set up.
Multiple options are available to integrate with the above
Type in smarthings hub in the search of their web site and one should find the relevant devices . Check your own country samsung web site for compatibility.
Another company that provides value is Shelly. They supply multiple sensor types including water leak sensors that integrate with the power unit below.
I have not purchased this unit but it looks like good value at €69 but it uses wifi. It is made by Shelly https://shelly.cloud/
A unit that measure power consumption and provides a Bluetooth option also looks like good value. It is the AT3010 AC50~320V 100A 3KKW Phone App AC Meter. It costs around €15 and can be purchased from https://www.banggood.com . It will need an enclosure to house the unit and it does not use wifi which is a benefit. I purchased this unit as a test and I am about to set it up. I will use this meter to monitor the cost of heating the house and also monitor the condition of each storage heater.