Help!! Air source heat pump costs

ariarnia

Evan3020 said:

I have solar but I use 1.7 kwh a day and am just reading up on whether I can save another 5w an hour during the night by switching off my router.

@Evan3020
not to derail the thread but i read that was a bad idea. turning off and on your router can be interpreted by your internet provider as dropping the connection so they can reduce your speeds to stop it from happening. 

MattMattMattUK

Another thing to look at is when the heat pump is running. It is more efficient the hotter the outdoor temperature, so the ideal time to run it is the afternoon, the worst time to run it is overnight or first thing in the morning.  I do not have an ASHP myself, but a friend does and nearly halved the energy usage of his ASHP by changing the times when it ran. Also you need to look at the profile of the ASHP, it is a "low and slow" level of heating, if you ask the system to bring the house up to temperature too quickly some have a boost function, which is effectively an immersion heater, when that kicks in you lose the multiplier effect and it becomes 1:1 in terms of electricity in and heat out.

Rodders53

You need to find the exact model of Daikin to get 100% accurate advice ---- from the experts here (not me ).

These heatpumps can have a reasonably significant  'vampire' load when left on - even in standby - 24/7.  There have been other threads on this recently (and in the past).

One Mitsubishi HP user's standby figure was 22 W (528 W a day) another system (Daikin similar age to yours) consumes 120 Watts (2.88 kW a day).  The user of that HP now switches the system off at the mains in summertime, and just reheats their HW tank via the HP every other day (and that suits their use - your mileage would vary, but seems fairly similar to me).

Installers leave HW on 24/7 for ease - in theory the HW tank thermostat is enough.  But better energy control is possible by an intelligent user and timers.

MrsBeee

Rodders53 said:

You need to find the exact model of Daikin to get 100% accurate advice ---- from the experts here (not me ).

These heatpumps can have a reasonably significant  'vampire' load when left on - even in standby - 24/7.  There have been other threads on this recently (and in the past).

One Mitsubishi HP user's standby figure was 22 W (528 W a day) another system (Daikin similar age to yours) consumes 120 Watts (2.88 kW a day).  The user of that HP now switches the system off at the mains in summertime, and just reheats their HW tank via the HP every other day (and that suits their use - your mileage would vary, but seems fairly similar to me).

Installers leave HW on 24/7 for ease - in theory the HW tank thermostat is enough.  But better energy control is possible by an intelligent user and timers.

It looks like you have somewhat hit the nail on the head. 

The HP and heating fuse simply being on at the fuse box with everything else off is drawing almost 80w. I have been though the whole house again and the fridge is expensive as suspected. 

I have turned off the hot water except for 1 hour in the morning but this hasn’t had the huge impact I thought it would. I will try the suggestion of running this hour in the afternoon instead. My costs are the same as they usually would be at this point in the day sadly 10.5kwh. (Although I didn’t amend timer until this morning so tomorrow will be a better indication). 

Turning it on every other day isn’t really something I’d like to do ideally, purely because I will lose track and no one likes a cold shower. I’m also concerned about the legionella cycle. 

Evan3020

Switch stuff off at the fuse box and keep checking that meter and you will find the culprit.

MrsBeee

Evan3020 said:

Switch stuff off at the fuse box and keep checking that meter and you will find the culprit.

I have done exactly this the culprits are: 
heating/ water controls 80w
fridge 120w

Evan3020

But that does not add up to 10.5 or 16 kwh a day. 
Maybe without the hot water heating tomorrow?
Do you have an immersion heater as well as the ASHP for water heating.

ariarnia

it would add up to 5ish? then another 5 could easily be day to day things like lights/cooking/tv

I think 4 or 5 kilowatts a day is about normal/lowish use isn't it? (if the 'average' is 3000 per year then the 'average' is around 8 per day) it was 10+ a day that was excessive/needed explaining. 

Mstty

So that's your baseload Heat Pump chewing 2kwh and the Fridge freezer nearly 3kwh. call it 5kwh with a router running for the internet?

Hot water may well be using 2-3kwh on an older heat pump but there is some good advice about running that when the sun is out during summer.

So where is the other 8 kWh. 

1-2kwh depending how old your washing machine is.
1-4kwh if you use a tumble dryer

Cooking what do you use?
TV and entertainment?

You have answered the weather compensation question so the interesting questions are

Has the usage gone up over the years

Is the heat pump regularly services

The location of the heat pump and cylinder suggest there will be heat loss along the way so you would expect a higher than average usage.

 

MrsBeee

Sorry, I probably should have explained. 

The boiler is using 80w even when it’s not heating the water. I have an immersion which tops up the hot water where required, yes. 

The hot water will peak when it’s heating, using a huge amount of energy I expect. I haven’t seen this spike to be able to advise the usage. 

As the immersion was on 24 hours until just after 6 this morning, today isn’t a great example and I will report back tomorrow. 

I tend to cook a one pot meal on the hob, or a combination of a hob meal with a jacket potato in the air fryer. We each have a slice of toast for breakfast usually. I don’t use the oven/ grill regularly. 

I’ve done one wash today but I didn’t track. I don’t have a tumble dryer. We have a dishwasher. My appliances are all less than 4 years old, washer and dishwasher are 2. Except the fridge which is 12 years old. 

We have 2/3 year old tv which we tend to watch for a couple of hours after dinner. We have no other entertainment/ sound bar/ sky box/ DVD player/ radio. 

We always have the internet router on. 

Usage has not gone up, it’s always been consistent summer/ winter apart from one very bad, cold December when usage was higher but I can’t remember the exact amount. It was last serviced 2 years ago.