It may be but if it’s on a timer, one would think it would be for domestic use so as to provide instant hot water in the mornings or from preset periods when hot water demand is higher. To have it shut down, say overnight, is an energy conservation feature.
I’m involved in a litigation in a supposedly highly efficient all-electric house (with HP/AC) where the costs are much higher than projected. It has a 60 Imperial gallon electric hot water with 24 hour recirculation. Poor pipe insulation and the continuous heat loss is putting bills up:
(1) the straight cost of electric resistance `supplied heat loss from the pipes takes away from the running time of the heat pump at approximately 50% heat savings. There could be 2000-3000+ watts of pipe heat loss all day that prevents the HP running at its most effiecient levels during the mild shoulder seasons when COP’s of 3-5 are attainable!! This may be enough to keep this well insulated airtight house comfortable.
(2) in the summer, this is an added internal heat gain that causes the AC to run longer.
Both of these items are costing the homeowner!!!