Home Power Usage
General Consumption

The second question was:- What does my house use without us

Or to put it another way, how much power does the house use when nobody is home. Its a simple question and you'd think is was a simple answer - NONE, or at most very little. We're all trying to save money, and not paying for unnecessary power is one way to save. OK, it might not be the most genuine of reasons to do this, but the reason doesn't really matter. From the electricity bills, you can average the daily usage and for my house in 2009, its about 13KWh / day. So to reduce the power consumption you have to know where those savings could come from. Most of my lights are energy saving ones so already done a fair bit along those lines, so the question is, where to try and save now... The results were somewhat surprising.

Obviously the best time to see what the house is using is when we're not there (not very often), or when we're all asleep. Its a bit difficult to look at the monitor when you're asleep or out and about. Leaving the monitor connected to a pc means using even more power. There's something wrong with this picture. We're trying to save money (power) and we're using more. Sounds a bit like a government activity.

Another complication is that the power monitor uses (very little) power and needs to be on 24/7. OK, thats a cost that can be covered. You're (I'm) looking for bigger savings than the odd penny or watt. The power monitor is supposed to be less than 1W so about 1 per year. A pc is another matter. We use pc's all the time, but to keep one on just for the monitoring is a little extravagant. So thats not going to happen, but doing so for a day, night or specific period of time to get data we don't have is acceptable (to me anyway). This capture was done for a few hours one night (also back in June 2010).


The results of the test

What was immediately surprising was when everything that should be off, was off, the power being consumed appeared to be around 200W. That was a lot higher than I expected. 200W 24/7 is 4.8KWh a day. Thats a sizable amount of my daily usage so if there's some wastage there, it will be worth saving. The peaks towards the end of the above graph hides the detail of the stuff we're interested. So by ignoring the end bits another graph is much more interesting.

The 'hovering' appears to be around 210W-220W with lumps of extra bits. Its a good bet (I've yet to confirm it) that the lumps are the fridges and freezers pumping away doing what the're supposed to do. Again, thats a cost that can't be avoided (without having all the food go off) so we can ignore those. The central heating pump (also used for the hot water tank) is unavoidable. So where does that leave us. Well, if some of these 'lumps' get bigger (using more power) or stay on significantly longer then it might be worth having a closer look at that appliance other than just putting something in to taking something out (is the door shutting properly, is it iced up) or failing in some way.

But as 5KWh a day looks to be continuous use, any savings there, would be 24/7 savings (or hopefully something that can be turned off for at least the night - making the saving 12/7 which would still be useful). But, 200W continuous use, and thats NOT the fridge or freezer pump going, well if you've read the other page to this one you will have seen the TV arial booster draws 9W. It could be turned off for a few hours a day, but its a pain and if we want to record somthing late at night or when we're out, it cuts down on how long it could be off. While we're on the subject, I have two tv arial boosters, a masthead one and another that takes the signal out of the lounge video and splits it to the other TV's. Lets say the other one uses the same amount, then thats 18W of the 200W (nearly 10% of what we're looking for).

However, it set me on the course for finding 180W (after deducting the two tv boosters). I haven't got it all itemised as yet. But I did start to look at the things that are permanently on. By the time I finished, I had 42 (fourty two) items in the house that are left on permanently. And what's worse is that they are all annoyingly small things.

Make that 43, as I now have a wireless web cam permanently on, and as you will see from my web cam page, thats 1/10 of a KWh per day.