0 to 60, in about half an hour

As a youngster, I loved colouring-in. Luckily for me, I grew up during the hey-days of the 1980s, when the prizes on offer for colouring-in competitions were, frankly, amazing.

These days, a kid would be lucky to win a corporate fridge magnet as a prize - but as a teenager I won an actual fridge (plus a washing machine, as well as literally dozens of other awesome prizes, including a flight in the blimp over Sydney harbour, and a Dragons rugby jersey signed by the team).

Anyway, one of the best prizes I won was a solar hot water system to go on the roof of the family home. That was in 1987, when I was 12, and that baby is still producing hot water for my mother to this day. (My Mum reckons that the fancy paint set she bought me for my 10th birthday - which seemed extravagantly expensive at the time - was one of the better investments she ever made).

A blast from the past: "Samantha's in hot water" (and in the local paper). I'm sure my Mum was proud, but I got teased pretty badly about this at school. Nevertheless, I was chuffed.

Now, 24 years later, I've finally got a new solar hot water system of my own, and I couldn't be happier with it.

We chose an evacuated glass tube system this time - and the tubes are fantastically effective at gathering heat from the sun's rays.

This was about 30 minutes after the evacuated glass tube collectors had been installed - and even on such a gloomy afternoon, the exposed section of the outlet pipe was too hot to touch. Love it!

One of the many things I'm enjoying about our spanking-new set up is that solar hot water systems have become a lot more interactive over the past quarter-century. In 1987, the interaction we had with our solar system was basically limited to flicking the electric booster switch on if the water felt too cool. Now, we have a fully interactive control panel which, among other things, shows you the precise temperature of the water at the collector, and in the storage tank.

The Solar Controller - for hours of interactive fun! (This reading indicates that the water in the tank - "T2" - is at 55C)

At 6.30 this morning, the tubes were icy, and registering a temperature of -1°C, while the water in the tank was 55°C. The maximum temp in the tank is 60°C (to avoid burns) - thus, the hot water in the tank lost 5° over night (for the record: nobody used any hot water after sunset yesterday). This overnight heat loss is not ideal, but, then again, 55°C is quite hot enough for a generous hot shower should a person happen to want one in the morning - using rain water collected from the roof, naturally!

At 6.30 this morning the evacuated glass solar collector tubes were icy - but not for long!

And, as soon as the sun peeps over the escarpment in the morning, the collector starts ticking up through the degrees, generally (at least while I've been watching it) at two or three degrees celsius per minute.

The sun, arriving for work at 6.30 this morning

It's now 1.00pm, and I've just checked the readings again. Although the day is currently overcast, the collector is sitting at 100°C, and the tank is sitting at its maximum temp of 60°C.

I'd almost forgotten how much fun data collection can be!