HIU - Hot Water Billing

razord

The ultrasonic flow meters are pretty unreliable, though usually they fail in your favour (under-reporting usage)

I have a HIU and a 5 minute shower will cost me 3-4kwh. My shower is pretty high flow rate and hot too... so 11 seems excessive! I pay about £23-£25 a month for hot water and showers (though, that is just me).

Do your meter let you see the current inlet and outlet temps, plus the water flow rate?

macman

Comparing the 11p per kWh cost to that of an individual gas boiler is not really realistic. Of course the central HIU boiler will be gas fired, at a commercial kWh rate, but, in the absence of an HIU system, each flat would be reliant on individual electrically powered systems, either electric CH, or an immersion heater and convector rads.
The only cheaper route here would be E7 with NHS's, and few developers will install that by default because of the higher capital cost. Obviously not an option here if the OP is renting.