Heat Pumps - post here.

As @graememk said You’ve got two really heavy periods of use during peak times morning and evening. Figure out what’s causing that and move those things to night rate if possible. You have minimal usage otherwise. So when is the hp producing hot water? Is this timed for morning and evening perhaps and if so why not on cheap night rate.

some recommend running the home on demand for heating others like me run ours at night and let the floor release the heat throughout the day but then that depends on your building.

you have low usage between 2am and 7am and more during daytime. Do you work from home? If not what is using more power when you’re not there than when you are. If it’s the hp I’d set timers.

You may burn more kwh hours this way but if those units are substantially cheaper you spend less. Night time units tend to be greener so the environmental harm of the extra units is somewhat off set. Well that’s my justification to myself anyway 🙂. If you understand and can change setting without stressing you can always give it a go and then change back if it has no effect on the bill or it effects your comfort level.

Your usage should be less in the summer so may work out at they have said. The spikes are the most interesting. If you could work those out as to what they are you’d be sorted. Do your radiators get hot at those times more so than others?? If not I’d bet it’s a hot water setting on the heatpump unless your making 3 course hot breakfasts and again in the evenings with the drier rocking.

EAB is based on an average consumption of 4200kWh per annum as advised by the Commission for the Regulation of Utilities (CRU). If you go into bonkers.ie and input your annual consumption figures you will get a more accurate estimate of your annual cost. Alternatively you could create a spreadsheet to calculate the cost based on the plan you are on.

Its very confusing for lots of people,most if not all installers are advising to have heat pump on all the time,which is the most efficient use of heat pumps but it now turns out it is probably the more expensive option as well.

@igCorcaigh (as ECO_Mental pointed out) this is the first thing you should be addressing, also try to shift as much as possible your consumption to night rates, appliances and HP by setting the thermostat temp slightly higher overnight (on the cheap rates) which will keep the house warmer during the day with less electricity usage (at the more expensive rates)

Well, they are red flags anyway.... low pressure and temp sensors not working are going to cause you running problems.

You need to get those fixed first. Its a new build so there is no excuse for the installer to be walking off site with those alarms active. Get them back asap, as the longer you leave it the less chance you have of them fixing it under warranty.

Then reassess what your running costs are like after that.

I'd recommend you invest in a cheap clip on energy monitor and attach it to the HP, then you'll have a good idea what its actually costing.

Check and see if the heat pump is actually running when it's calling for heat. With those errors it is possible that it will just run the immersion to heat all your water instead of running the compressor.

Your morning and evening peaks are possibly domestic hot water heating. On install, most heat pumps are set to heat hot water on an as needed basis regardless of time, so if you have a shower it will replenish the water immediately. From an economic point of view it makes more sense to heat your hot water on night rate only, unless you find you are running out of water during the day. The temperature of the hot water probably has 2 settings. One is the flow set point which will be set on the heat pump, and the other is the desired set point of the hot water cylinder which will be set using a thermostat on the cylinder. The cylinder thermostat could be a mechanical thermostat or a temperature setting on the heat pump control panel.

Also, what's the switch that's turned off beside the expansion vessel?

@igCorcaigh also bear in mind that a new build will be drying out for the first 18 months or so, so expect higher energy usage during this period.