Home Forums General Discussion Very high energy bill in 8 year old house – no apparent cause Reply To: Very high energy bill in 8 year old house – no apparent cause

Ian McChesney

Hi Sarah
Good to get the time of use data to see what the patterns are, but it sounds like you have pretty well sorted what is going on here. These calculations are a bit speculative but: – the hot water use for showers alone suggests about 700kWh in the month. The lighting could be adding up to 500kWh – most of which will be heat going into the ceiling I suspect, as well as heavily compromising the insulation. Add to that HRV fans (could be 100+kWh depending on amount of use – and also check whether they have any in-line heating elements which could add another 1 or 2 kW ), the heat pump (4 hours per day at ~1.2kW (for a small HP) gives ~150kWh), maybe another 100kWh for the spa (and this might be low), computers/TVs/games consoles etc, esp if lots of use from teenagers, could be 100-200kWh, washing/dishes/other hot water etc (another 100-200kWh), plus cooking etc and we’re up at ~2,000kWh.

The lights look like one area where some decent improvements could be made, and a good, lower flow shower head might be effective at cutting the hot water use (I’d go for technical solutions over behavioural solutions where teenagers are concerned…).