How does that work then?

A friend asked me about the heating and the miles of big grey pipes, ‘is that part of the heat pump?‘ he asked, quite reasonably. I realise I’ve rather assumed everyone knew about this stuff, but of course many of you probably don’t, so a brief explanation seems in order.

But first I can announce I’m giving up work. Well, for the London Borough of Hackney at least; the house goes on. My sabbatical ends at the end of April.

I’m also happy to tell you the larch cladding on the west gable is complete, as of today.

We’ve been lucky with the weather these last two days; though forecast wet it’s been dry, the procession of ominous dark clouds passing without incident, until four thirty today as I was nailing the last board. Another grey wedge loomed overhead, the gusty wind became strong and chill then the air was full of hail. I finished before it turned to rain.

In ten days Hyperion Zero are hoping to come to fit photovoltaic panels for us and the neighbours. We’re both up for a discount with installation at the same time and neither of us is investing in batteries yet. The technology seems to be moving so quickly and our system has been specified to be ready to plug in a battery as and when. Perhaps, with a bit more lucky weather, I can finish the roof by fixing the fascias as well as barge boards and metal verges before Wednesday, when I’ll be barred from any heavy lifting for six weeks… but what is ‘heavy‘?

How does that work then? Fed up with living in a draughty, energy-hungry Victorian house and wary of energy becoming much more expensive as I got older I aspired to build a ‘passive house’ (see Passivhaus Trust – https://www.passivhaustrust.org.uk) and, though our house won’t quite meet the criteria, it is close. The idea is to use minimal energy and to do that the house is airtight (as airtight as possible), super-insulated and set up to gain some heat directly from the sun (passive solar gain). The airtightness prevents hot air being lost – but if it’s airtight you need a mechanical ventilation and heat recovery system to expel the stale air, recover its heat and use it to warm fresh air coming in. This doesn’t mean you can’t open windows, but when they’re closed there are no draughts – you’re in control.

Our heat source is a heat pump – like a fridge in reverse. A fridge is an insulated box that takes the heat from what you’ve put in it and pumps that heat to the outside; in our house, the heat pump takes heat from the outside (air) and pumps it in – using it to heat water inside the house. The heated water warms the underfloor heating as well as hot water for kitchen and bathrooms.

The local horse chestnuts are just coming into leaf and the sallow or pussy willow is just flowering – as it should around Easter. Last weekend, for the first time in months I stalked the plot, looking for the cuttings and transplants I put in last year. Although nearly all of the cuttings looked fine when they last had leaves, a fair number are now crispy and without new buds. We went into the woods and I cut a dozen hazel rods to start filling gaps.

There’s quite a bit more of this to do, as well as plenty of rampant bramble to try to keep on top of, to make sure it doesn’t smother new plants before they’ve become established.