In which I post some charts

We've had the heat pump installed for getting on for 8 months now and have nothing very dramatic to report. It switched itself off for a few days in February when the pressure in the brine loop went down dramatically. It is thought this was caused by air in the sytem working its way through. Zander came and added in some more brine and its been fine since then although the pressure has slowly dropped. We're hoping this doesn't mean we have a leak somewhere but I have a nasty feeling it does. Apart from that it's just done its stuff without any drama.
Since the pump was installed I've tried to record each week how many hours its been operating, what our total electricity use has been and various other things that I think might be useful. I've put this in a spreadsheet and from time to time drawn pretty charts. (There's definitely something about renewables that leads to slightly obsessive behaviour.)
The three charts below show -

• the electricity use per day over the preceding period (in kWh)
• the number of hours the heat pump was operating per day over the preceding period 
• the number of hours our solar panels were operating over the preceding period. (The long period when the solar panels weren't producing anything is when the roof was being re-slated and we had to take them down.)

Update

Just a brief update to say that everything with the heat pump is fine and rosy. The house is continually very nice and warm. The only room that could do with being just slightly warmer is the living room but we don't use that much anyway and have the wood burner for the days/evenings when we really need to.

We also still have a minor Somme in the garden where they dug the trenches to the bore holes and put in the manifold. We'll probably wait until the weather's a bit warmer before doing anything about that.

I'm keeping a close record of electricity usage and heat pump activity which I'll post once I've got enough data to make sense of it. So far, for the most part it's pumping the water through the radiators at somewhere just under 40 degrees except for the few days we've had that were *very* cold when it was up to 50 degrees.

At some point, I'll also post about the total costs etc. and also add some extra pictures of the machine itself.

Heat!

We've now had the heat pump in and working for over a week and are very, very pleased. It was first switched on last Tuesday evening, around 6pm. I was out for most of the evening and got back around 10pm when the house was already noticeably warmer and we had a full tank of hot water. Since then it's just been purring away, doing its stuff without any fuss.
Getting it here turned into a bit of an epic because although it had been loaded onto the Ecoliving delivery van on the Friday ready to arrive on Monday, it turned out to be the Monday when this happened so there was no chance of it being delivered on either Monday or Tuesday. However, Ecoliving managed to get their van out of the snow (it had been immovable for a couple of days) on Wednesday and were aiming to get the heat pump to us. We were still faced with the problem of getting the heat pump up the drive because there was no way the van would make it up there. Thankfully we were able to press-gang  one of our neighbouring farmers, Dougie who was prepared to come down with his tractor and transport the heat pump and water tank from the back of the van up to the house.

I think everyone was hoping we might have it up and running by the end of the week, particularly because temperatures had starting hitting -15C so the parts of the house where we didn't have the wood burners on were becoming seriously cold. But despite the efforts of Zander (who was doing the installation), Graeme who was sorting out the electrics and Alan who was connecting the bore holes to the house, we had another weekend without heating.

However, the mere act of progress seemed to make things slightly less unbearable and as described above we got to the big switch-on on Tuesday evening.
One of the concerns before we started was whether a heat pump would be able to heat an old stone-built, poorly-insulated house like ours and so far, despite the unbelievably cold whether we've been having it's had no problems at all. If anything, we've had to tweak the settings a bit to bring the temperature down.
There are a number of details we need to resolve, like the position of the outside temperature sensor, and as I write this we still have mounds of earth in the garden from where the trenches were dug but there's no point in trying to fill these in until the ground thaws (and frankly, at the moment we don't care as long as the house is warm).
A problem that we foresaw but which has been worse than anticipated because the weather is so cold, is that our boot room/boiler room is completely arctic because it used to be heated with waste heat from the oil boiler. This has now gone so there's no heating in the room at all. This means that the toilet next to the back door has started to freeze up (both the water in the toilet itself and in the cistern) and the clothes that are hung up aren't drying particularly well. We may end-up putting a radiator in that room or something along those lines.

Thanks are due to everyone for getting the installation done (Ecoliving, Zander, Alan, Graeme, Dougie and also Stephen the FDT energy advisor for helping get everything co-ordinated) and for coping with us jumping around every few minutes asking how things were going.

In which I moan about being cold...

The 3-phase meter was duly installed on 25 November as promised. Digging the trenches and installing the heat pump itself was due to take place this week and next. On Friday morning last week I was joking with our energy advisor that I needed to be careful that we didn't run of oil and that I would need to check the level over the weekend. All of four hours later we ran out of oil. More or less at the same time as it started snowing.
Since then we've been without oil and heating the house exclusively on the two wood burners which means that some parts of the house are reasonably warm while other parts have been (at times, literally) freezing. We can heat hot water electrically so at least we haven't been without that.
So this week has been preoccupied by trying to get the heat pump installed despite the weather. This hasn't been easy because our driveway has been impassable so even arranging for the heat pump to be delivered has so far been impossible. The plan at the moment is that everyone (including the heat pump itself) is going to be turning up on Monday morning and doing the installation early next week.
The other question of course, was whether it was worth getting any more oil. At first we thought we would just sit it out but then realised that actually we didn't have much choice given that the blocked drive meant that the oil lorry wouldn't be able to get up to the house anyway.
Seems to be snowing again at the moment. Ho hum. Chilly.

Three-phase meter

We finally have a date for the three-phase meter to be installed - Thursday 25 November - so hopefully we'll be up and running the week after that.

Update - meters and oil

We're still waiting to get our 3-phase meter installed and until that happens nothing much else is going to, although the trenches for the pipework connecting the boreholes to the house are supposed to be dug next week and, for reasons best known to themselves, Ecoliving kept trying to deliver our heat-pump this week.
As mentioned previously, we had an issue with our oil running out and the in-laws turning up. Eventually I phoned Bilslands the oil people, who said that their smallest conventional delivery was 500 litres, although they could deliver less but would have to charge more per litre. However, they also said that they could remove our old oil tank when we no longer need it and any oil they can recover from it, we will be reimbursed for. On this basis and with the threat of cold in-laws hanging over us, we succumbed and bought 500 litres. The other factor of course is that, while I would much rather not be spending it, in the grand scheme of things, an extra £250 isn't really going to make a huge amount of difference.
And it's quite fun having a warm house.

The fourth hole

When we left our heroes, they were just finishing off the third hole and about to put the pipe down it. We thought we were almost done with the drilling.
But, what happened next was that as the drillers were feeding the pipe in, at about 90 metres, they hit an obstruction. They started pulling the pipe back out again with the intention of re-boring the hole with the drill but when they started pulling the pipe out it caught on another obstruction. They tried everything to get the pipe back out again including tying it to the drilling rig and pulling it out that way but eventually it just snapped. I assumed that they might be able to clear out the pipe with the drill but apparently the plastic is so robust that the drill would just have bounced off it.

Feeding the pipe down the hole

trying to pull the pipe out again with the rig

The only option was to drill hole number four. We had a long debate about where to put this and eventually agreed that putting it on the lawn was the best option. Or maybe the least worst option.

Thankfully the fourth hole went very quickly and smoothly (although it also required a significant amount of casing - in this case around 35 metres) and they were finished it in a day and half.
We were pretty nervous about having the rig on the lawn not so much because of the mess it would make while drilling but because it might churn up they lawn while they were driving it on and off, and also having to have trenching across the middle of the lawn.

Moving the rig off the lawn once the drilling was finished

Knowing how nervous (precious?) were were about the lawn, the guys were very careful when driving the rig off. The mess left at the hole and over the lawn was absolutely minimal.

So, the drilling that was supposed to take four to five days has actually taken two weeks which was a bit of a pain but no more than that. We felt sorrier for the drillers who were completely gutted by what happened with the third hole, given they were so close to getting it completed.
It's also worth mentioning that the guys operating the rig were really good to get on with and very focussed on getting the job done. They also didn't mind us prancing around taking photos of them all the time and asking daft questions about what different bits of kit did.
I'm expecting we'll now have a short hiatus while we sort out getting a 3-phase meter put on the house. We already have a 3-phase supply so it should be a straightforward operation but requires Scottish and Southern to come out and do it so we're not holding our breath. Once that's done, we can get the trenching and groundwork done to get the pipes into the house, and then get the heat pump itself installed.
In the mean time, the in-laws and lack of oil are getting closer and closer. There's a sense of inevitability about the two coinciding.