Key to getting the best out of your solar PV system is knowing when you are producing more electricity than you are using. This is the time to do things that use the most electricity.
Of course, this isn't always possible. If you want to relax in front of the telly in the evening, the sun's probably gone down already. Similarly for boiling a kettle of water after your evening meal. But, if you're at home and flexible, there are things that you can do to maximise your return.
If your inverter is in the loft, or the garage it's not convenient to keep popping out for a look. This is why I've been testing an energy monitor that tells you what your panels are doing.
The Wattson Solar Plus* measures both the energy produced by your solar panels and the energy used in your home or business. It displays the results using colours and numbers, so you can use either or both according to your preference.
If you are generating more electricity than you are using - net export - you can see at a glance as the unit glows green (or the box displays a negative number). A blue light indicates that you're using less than average, purple equals average, and if you're using more than average it throws out a bright red glow.
I've found it fascinating. Whenever the usage goes up a notch I start wondering what's on - especially when it goes into the red. I've learned that our so-called Eco Kettle gobbles up a lot of kWs. But the biggest surprise was how much the oven uses, and how often we use it. Having always been rather suspicious of microwaves, I'm suddenly becoming a convert.
The washing machine isn't as greedy as I expected, and on a sunny day, there are only brief periods when it's using more electricity than we're generating, where I'd expected it to be a heavy user for the whole cycle.
Mostly my Wattson sits in the kitchen, as it's from there that I notice most of the big energy uses. However, you can pick it up and take it from room to room, so you can see the impact of turning lights or the TV on and off.
Once you've got it set up it's really simple to use, but I found it quite difficult to set up. There's a clear picture of which cables you put all the clips round, but my cables had all been neatly hidden away in some trunking by my installer. Luckily an electrician friend called round while I was busy scratching my head about it, otherwise I'd have been stuck (he clipped them around cables on the other side of the fuse box, but without his help I wouldn't have been able to tell them apart).
For those of you who are keen on spreadsheets and like lots of figures, you can upload data from the Wattson to your computer using special Holmes software. I'm still getting used to this and will review it in a separate blog in a few weeks time.