I bought a Heat Pump

Reed_Richards

Ah @Mstty , you always seem to do a bit better than me. You must have one or more of:

A smaller house.
A better insulated house.
A more efficient heat pump / heating system / control algorithm.
No desire for rapid hot water.

My January average was 29.0 kWh per day (compared to 26.9 kWh per day the previous January.  It was the cold spell in the middle of the month that pushed the average up.

Do you have a fancy weather station to produce all that temperature, humidity and pressure data?  I'm quite envious.   

Mstty

It could be down to a bit of both. 

Different manufacturers of heatpump ours in a Mitsubishi Ecodan 8.5kwh model (so lower kWh than yours) 7.5 years old.

I really could do with a seperate meter on the heat pump to get exact figures but we do know our baseline in winter and summer so it will be fairly accurate.

As an example January's total average 32.45kwh a day 1006kwh total. Of which 10kwh with the tumble dryer going more in winter was our everything but hot water and heating baseline.

The house is a big L shape with a vaulted ceiling one end and the other end with a second story. The vaulted room being the hardest to get up to temp it can read 18-19oC in there and 22oC at the other end for obvious reasons of another story on top and less head space to needlessly heat (I have noted a fan we could use to send that heat back down but visually Mrs mstty is not a fan pun intended)

EPC is a high B. House is a large 4 bed small 5 bed as the office/bed 5 is tiny. I did a remeasure due to re-flooring and have recently estimated it at 146m2 bit different to the EPC but hey ho.

I wish I had a home weather station monitoring but have to make do with our nearest weather station readings which is only 2 miles away and probably far more accurate than any home system I would put together.

matelodave

Just done a comparison of our January consumption over the past three years, Jan 2021 = 1373kwh, Jan 2022 = 1028kwh and Jan 2023 = 1135kwh but thats our total leccy consumption.

 I have tweaked our controls for this winter and instead of letting all the thermostats control the system (eight of them) I've set them to be high limit stats and and am now controlling the house temp just based on weather compensation which, although might be using a little more energy, has made the place much more comfortable as it doesn't cool down as much overnight and temperature is more even throughout the day.

It must be working because Mrs Matelodave hasn't whinged about being cold at all this winter which is really unusual, so the possible extra cost is worth the relative tranquillity. 

Like @Mstty we dont have a separate meter to accurately monitor our heatpump consumption and so have to guesstimate our baseload on our average summer consumption of around 10kwh/day which equates to just over 300kwh in the month. So I guess our heatpump use an average of around 27kwh/day this January

Our heatpump is a 12 year old Daikin 11kw t in a 140m2 detached 3 bedroom bungalow with an EPC or D. We live out in the Cambridgeshire fens where the wind blows.
We've got good insulation in the loft (around 300mm), the walls have rockwool cavity insulation from when it was built in 1986 and the double glazing was installed in 1999. Although it's not really open plan, most of the doors seem to get left open for most of the day except for two of the bedrooms. The third is the study/workroom which is in use all day.

The temperature has settled to around 18-19 degrees, which may not sound warm, but because of the underfloor heating is even all over and there aren't any cold spots or cold draughts so its quite comfortable - even in the bathroom

shinytop

4 bed bungalow from 1990 here, all radiators, about 170m2, EPC D.   We keep the whole house about 21 deg, set back to 17 overnight. We've used an average of 30 kWh per day for heating in January at a COP of just over 3 (I have electricity and heat meters).

I've been experimenting with Mitsubishi's room temperature control; it seems to use a bit more than pure weather compensation but does heat up the house quicker in the morning. 

matelodave

Its interesting that we seem, to be averaging somewhere between 25-30kwj/day which I gues sat this time of year assuming a CoP or around 2.5 (I'd doubt that most of us could achieve 3 at this time of the year) we are  using about the equivalent of 60-80kwh of gas. It would be interesting to get some info on people's gas consumption over the same period to do a comparison.

Doing the sums 60-80kwh of gas at 10.3p = £6-£8 compared with 25-30kwh of leccy at 35.13p (Eastern region) = £9-£10-50p a day so not outrageously more expensive than gas but at least those of us who are leccy only don't have a gas standing charge as well as an electricty.

shinytop

I think in the real world people might use less gas kWh than ASHP ones.  The typically over-sized gas system is better at heating parts of the house part of the time.  And sitting near a very hot radiator can give a localised effect that means the whole room doesn't need to be as warm.  And the more even, constant heat from low temp rads and ufh through the whole house is quite addictive.  

But like you said it would be interesting...

  

Screwdriva

matelodave said:

Its interesting that we seem, to be averaging somewhere between 25-30kwj/day which I gues sat this time of year assuming a CoP or around 2.5 (I'd doubt that most of us could achieve 3 at this time of the year) we are  using about the equivalent of 60-80kwh of gas. It would be interesting to get some info on people's gas consumption over the same period to do a comparison.

Doing the sums 60-80kwh of gas at 10.3p = £6-£8 compared with 25-30kwh of leccy at 35.13p (Eastern region) = £9-£10-50p a day so not outrageously more expensive than gas but at least those of us who are leccy only don't have a gas standing charge as well as an electricty.

We used 2335 kWh of gas in December '22 and 2005 kWh in January '23, as detailed in this thread. We use gas for heating, hot water and cooking. My observation is that the running cost of gas is roughly on par with heat pump SCOPS of 3.5 or lower.

Introduce 10-15 kWh of battery storage and associated smart tariffs into the equation and things change substantially in favour of the heat pumps, albeit at a larger upfront cost. 

Martyn1981

matelodave said:

Its interesting that we seem, to be averaging somewhere between 25-30kwj/day which I gues sat this time of year assuming a CoP or around 2.5 (I'd doubt that most of us could achieve 3 at this time of the year) we are  using about the equivalent of 60-80kwh of gas. It would be interesting to get some info on people's gas consumption over the same period to do a comparison.

Doing the sums 60-80kwh of gas at 10.3p = £6-£8 compared with 25-30kwh of leccy at 35.13p (Eastern region) = £9-£10-50p a day so not outrageously more expensive than gas but at least those of us who are leccy only don't have a gas standing charge as well as an electricty.

If it helps, we (3 bed semi) used 124 units / ~1,364kWh in Jan. That's for GCH, DHW and oven. We have reduced our GCH a bit by adding an A2A unit, which has helped a little during Jan. Given our PV is off-south, it'll help more each month now going forward, as will the reduced need for heat, and the rising COP.

Whilst we don't have a battery (yet), it's probably also worth mentioning that batts added to increase the returns from PV, will also allow for some cheap rate leccy to power HP's during the day. So a great package as all of the technologies start to lean on each other.

Many thanks again to the HP guys for all the informative posts, really helpful.

Magnitio

I'm currently going through the process of looking into getting an air-to-water heat pump to replace gas boiler, so interested in this discussion. Two of us in a 4-bed 1970's house that is reasonably insulated. Usage in Dec and Jan of 1310 and 1145kWh (37-42kWh per day). However, we do have the thermostat set to 17-18 during the day and 15 at night, with the odd boost to 19 in the evenings if it feels chilly. Also heat water with immersion if prices/solar generation make it feasible. If we moved to heat pump, we would probably have a higher average temperature in the house.

At the moment, given our current usage, I can't see much of a financial benefit. The main reason for considering the change is to stop burning gas completely.

Screwdriva

Magnitio said:

At the moment, given our current usage, I can't see much of a financial benefit. The main reason for considering the change is to stop burning gas completely.

With a nighttime tariff like Go/ Intelligent/ Cosy paired with batteries, you will experience a financial benefit as your gas consumption appears low for the size of your property. A heat loss calculation will help determine exactly what your SCOP will be, which will estimate how much you will save per annum.