Tag Archives: home

Watt’s the cost?

A few years ago, I came across a really useful rule-of-thumb for calculating electricity cost:

A 1-watt device costs £1/year, if it’s running 24×7.

At the time, this was almost exactly right for most people in the UK, and it made it very easy to estimate the impact of, say, using that old 200W PC as a server for the next three years rather than getting a more modern low-power one.

Sadly, for most of us, energy costs are going up a lot at the moment, and the above is probably rather optimistic now, so you might want to do the calculation for yourself. For example, I currently have a big Synology NAS server here at home storing lots of my data and backups. Once you’ve bought such a device, how do the running costs compare with storing your data in the cloud?

So here’s my exciting new highly-sophisticated web application, which is designed to answer this simple question:

Watt’s The Cost?

Hot at the top

This is a lovely idea – the Mixergy hot water tank.

A standard UK hot water tank heats the water from the bottom, either using electricity or water heated by a gas boiler. This means that when you want to heat up your water, you need to heat the whole thing.

Mixergy, instead, put the heating at the top, so you can warm up smaller amounts of water, and then make intelligent use of pumps to circulate it as required if you need to heat larger amounts of water. Not only is this more energy-efficient, but it means you get hot water again more quickly after you’ve used it up.

There’s a more detailed discussion on a recent episode of Fully Charged.

© Copyright Quentin Stafford-Fraser