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.