Saving electricity

As you can imagine, utility bills are rather high in a guest house.  This time the electricity bill was the subject of attempted cuts.

We are fortunate in that our house has been fitted with a three phase supply.  The highest consumers of electricity (but not the most expensive) are the showers.  With a three phase supply we can have more showers running at once.  We did have 6 showers and a water heater.  At an average of 8kW each that could be some 48kW at once, which equates to 192 amps.  Most households are only supplied with a maximum of 80 amps.  If you use too much, the main fuse will blow which can only be replaced by the electricity company.

Some high powered commercial appliances can take advantage of a three phase supply for more power.  However, we use the three phase supply as three separate supplies. 

To monitor the electricity we have an efergy energymonitor.  It comes with one sensor which is attached to the incoming electrical supply lead.  The transmitter does have space for 2 more sensors so we bought another two and plugged them in and attached them to the other two phases.  The grey box is a smart meter, the small white box at the bottom is the transmitter.

The transmits transmits (wirelessly) to a readout and to an efergy hub which is connected to the internet and uploads our energy usage every few seconds.  

We also have an instantaneous readout so we can see at a glance how much electricity is being used.  In this case my wife is cooking which accounts for 2kW.

We can log in to the efergy website and see our electricity usage wherever we are.  There is even an iPadapp which shows your usage.

Previously we could see that overnight our electricty consumption ran at around 800 watts.  At 11p per kW this works out to around £770 per year when the house is "idle."  We decided to do something about it and find out where the electricity was going.  We chose a quiet time when we had no guests.  Everything was switched off and then various consumer units (we have 6) were switched on in turn and a reading taken.

There were a few surprises.  We have two Whirlpool washing machines which are A rated.  But the rating applies to their washing capabilities.  When they are switched off on the front, the small one takes 14 watts and the large one takes 17 watts.  That's £30 a year just to have them plugged in!  They are now on an easy to reach socket which enables us to switch them off when not in use.

A coffee machine takes 14 watts.  Our Miele dishwasher takes 9 watts.  And these are all switched off.  And the biggest surprise, our very old Panasonic microwave takes 77 watts just to be switch on. These are all switched off at the socket when not in use now. 

We have a computer for running the CCTV system and uploading the weather statistics to our website every 15 minutes.  I worked out it costs us £138 per year just to leave it on.

Our main computer is now connected to a one-clickdistribution board so that all the peripherals get switched off when the computer is off (printer, scanner, external disks, monitor).  However, the board has since broken so I have had to resort to manually switching it off and on.

To get internet to all the rooms we have 3 routers and a TP-link wifi extender.  The network has been redesigned to eliminate the need for one of the routers.

All these changes should result in a saving of som £130 a year, 10% of our electricity bill.