This could get obsessive. Yesterday the plumbers finished installing our solar water heating panels - two out-sized black oblongs and a dizzying array of pipes and dials. At the hub of all this, tucked away inside the upstairs airing cupboard, is my new favourite diversion from writing, nappy changing, and life in general: the solar display panel. On its small screen is displayed the temperature of the liquid (called glycol) going into the panels and that of the stuff being pumped back from the panels to heat the water in our storage tank.

Now, February in Scotland is not renowned for sunshine, but today we were blessed with a stunner. At 8am and with my entire cold-ridden family huddled under a duvet and waiting in sniffling expectation, we watched as the sun came up and the panels got hotter, and hotter. By the time I'd walked the dog the panels were up to a sultry 25 degrees C and my eldest daughter, Maddy, was giving half-hourly updates on the upward progress of the temperature. The peak temperature of the panels on this sun-drenched winter's day was 55 degrees C, and by the time the sun started to sink behind the hills we had ourselves a whole tank full of solar heated water.

In our house, as in most, water heating is a big energy user, and so one of our biggest sources of greenhouse gas emissions. The nightly bath for the kids, the bucketfuls of nappies, and the acres of washing up mean that we get through a lot of hot water in a day. Our boiler is a good one - a new condensing type that is supposedly over 90% efficient - but it still burns gas, and so it still emits carbon dioxide.

 The solar panels are another step towards making our home carbon-neutral. They haven't been cheap, costing £2000 from ourselves and £1000 from a government grant, but in terms of savings in energy bills and the cuts in greenhouse gas emissions I have no doubt they're worth it. Jumping into the shower this afternoon and knowing that the hot water pouring down was effectively carbon-free was nothing short of joyous. Here's to a sunny day again tomorrow!