Exhaust Heat Pump: Why are my bill's so high?

​@joshantmann it's always hard to compare different types of properties, so I'm reluctant to say whether your cost is good or bad. 

Just another thought, what's your hot water schedule set to? How hot is it set to heat to and is it constant reheat or scheduled?

So i believe there is no set heat or schedule due to how the heat pump is setup. I think ​@juliamc looked into this and found something similar

If there is a setting, or schedule, for that I haven't found it

That graph is from the heat pump app so only shows the amount of electricity used for heating and hot water. We do have gas but only for the hob, we also have an EV so our actual electricity use is higher than on the graph. 
Are you able to see how much electricity just your heat pump is using ?  Maybe an individual meter in your consumer unit ? Also giving your usage in £s depends very much on the tariff you’re on. 

Do you know what temperature your hot water is heated to and whether you can adjust it ? 
 

Here’s the heating + hot water usage for the last week. As you can see those cold days used a lot more than the not too bad days we’ve had recently.

I don't think i can see what my heat pump, alone, is putting out. Above is my usage for this month so far. A few wild days which I really don't understand. 

I'm not sure i can adjust the hot water. I need the login details to get into the settings on the pump. I can see it says 'heat request' on one setting. Not sure what that means

Those wild days match my heavy use days (Saturday and Sunday 11th 12th Jan) when the temperature dropped below minus 3. I think you’ll notice an improvement in energy use as the weather warms up.

I can’t see anywhere in the manual (assuming it’s the right one for your model) that mentions the temperature of the hot water. It unlikely that it’s user-adjustable. 

Another thought: can you see your half hourly usage on your OVO account ? That might reveal what’s happening throughout the day.

So this is from Friday. A few things I don’t quite get.

From 2am-4am there is clearly some usage. No idea what that spike is as I was in bed about midnight. There’s also a big spike at 7.30am until 9am. I didn’t get up until about 8.30 that day so, again, I’m not sure what that is. The temperature was set, as you suggested, to 18c for 24 hours.

Any idea what those spikes could be? The total usage for the day was 25 kwh so nothing out of the ordinary.

I think the water heating is a strong candidate. Is there a similar pattern each day ? I’d like to know more about how this system decides when to heat the water as it clearly wasn’t when you’d just used it.

Mine is set to “reheat” which means the hp stops heating the radiators and switches to do the hot water whenever the tank temperature drops below a certain amount, 30 deg in my setup. It almost never does a reheat as I have scheduled heat ups too.

Yours on the other hand keeps the water at a certain temperature all the time and I suspect it’s using the immersion.