On Sat, 27 Jan 2018 12:00:24 -0800 (PST)
wrote:

On Saturday, 27 January 2018 19:47:28 UTC, Rob Morley wrote:
On Sat, 27 Jan 2018 17:58:19 +0000
Vortex12 wrote:
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Or a 40 watt bulb in a biscuit tin. :-)

bulb failure - freeze - leak. No. Those days are past.

Anything can fail, and you can add appropriate levels of monitoring or
failover as necessary. A microprocessor system that monitors the
current drawn by the heater and the temperature of the water, and sends
warnings by email (or buzzers and blinkenlights) would be as useful to a
bought thermostatic heater as it would to the light bulb in a tin.