On investigation the Gledhill system maintains the hot water at 82 degrees (optimal temp to kill bacteria, apparently) so throughout every day, the unit demands the bolier to fire and supply a top-up feed. The bolier is an Ideal Caradon 70FF wall mounted gas boiler with programmer and room stat control. All rads except bypass units on first floor in bathroom circuit have TRV's.
As the house is 2 1/2 storeys, the system is pressurised to maintain sufficient supply to heating and DHW systems.
This surely isn't efficeint and as there are only two of us and we use showers daily and cook with Electric, our gas bills are averaging £150 for Electric and £270 for Gas per quarter, which seems very high indeed!
Would we be better off replacing the boiler with a condensing combi and ditching the thermal heatstore or use a dual coil tank with condensing boiler and fit solar panels to the second tank coil????
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energywise