Electrickery

When we first moved into our current house I projected our electricity bill to be in excess of 7,000 kWh for the year. This was in excess of the electricity bill for our old house which didn’t even benefit from a gas cooker. I’ve managed to bring it down, largely by replacing the incandescent lighting with fluorescent or LED lighting and replacing one or two appliances – notably our old CRT television. It may seem like tinkering at the edges but replacing our dining room incandescent lights with LEDs reduced the power consumption from 360W down to 32W. With the lights used for just 2 hours a day that equates to 239kWh of the annual bill alone.

However, for all my efforts to reduce the power usage on the house I have struggled to get the annual consumption below 4,000kWh which is still high for a house of this size. There are one or two things I could do to reduce that figure – we still have incandescent bulbs in the bedroom as this would involve a rewiring job on the dimmer switches and the number of electronic appliances keeps growing. But what are the big consumers? I have a meter plug which measures the power consumed and transient (and peak) power consumption. Over the last week I have been plugging this into various appliances to see what the big offenders are.

I started off in the kitchen. Traditionally, refrigeration is a major power drain. I can recall having a faulty fridge-freezer many years ago that caused my electricity bill to double in the months before it failed, leaving a wet puddle on the kitchen floor. Our current appliance, whilst large, is very new and was rated at A++ on the efficiency label. Over a day, it clocked up 0.76kWh – around 277kWh over the year. The other major kitchen appliance is the dishwasher. Due to the effort involved in moving this to install the meter plug I didn’t bother measuring it but I did check the model. It was launched in 2005 (we inherited it with the house) but was rated at AAA at the time. What this translates to is that it uses something in the region of 1kWh per cycle. However, we rarely use the standard 60°C cycle and find that the 50°C one suffices. The dishwasher does get used once per day so it will add up but I’ll work on the assumption that this is saving us on the hot water bill.

I suspect that the laundry bill is the biggest hit. The washing machine is used at least once per day (on average) although we do use the more efficient cycles. I measured our standard 40°C cottons cycle and it clocked in at 0.7KWh. What surprised me with this is that the bulk of that use came in the first 15-minutes. This is accounted for by the machine heating up the water and it does show that the very long (but relatively cool) cycles of modern machines are more efficient. It also makes the case for using 30°C or even cold cycles where possible. The next thing I tried was the dryer. We try to avoid using this when the weather will allow us to dry outside but our climate is not particularly forgiving in that respect. I dried the cotton load from the washer and it clocked in at a whopping 2.49kWh. This is probably a worst case scenario but it came in after I had cleaned out the condenser and filters. The dryer is getting old and excessively noisy and the efficiency of the latest generation of dryers has improved dramatically so this may well be something to save up for in the Autumn. The last part of this was the ironing which came in at 0.33kWh – of course not everything needs ironing but I find that some items need ironing when dried outside that don’t when done in the dryer. There is probably some crossover-point where it is more efficient to use the dryer – although not with our current unit.

I had to cut the grass and measured this. The mower used up 0.4kWh although as this was the first cut of the year it took a little longer. I probably use this somewhere between 20 to 25 times a year although last year was considerably less with the cold spring and dry summer. Other oddities around the house include things like the router and home network which ticks over at around 8W and although I didn’t measure the PC (which is quite a power hog) the new PC boots up quickly and uses hibernate effectively. I did measure my works laptop which I used from home and used a fairly reasonable 0.125kWh over the 9 hours I had it switched on. Possibly a bigger surprise was my son’s Android phone which only required 0.008kWh to charge up from flat – somehow I imagined that these were higher. I also noted that the charger didn’t register when left in unplugged which seems to be another myth-buster.

Home entertainment is a another power drain. Swapping the CRT TV for an LED unit helped to reduce this but part of the problem lies with standby modes. On our main living room setup none of the units (including the PVR) registered a standby drain with the exception of the Wii which came in at 1.25W. This is to be expected as they are mostly fairly new units and come under the latest EU legislation. Under use they do consume quite a bit but I have set the various eco-settings to minimize power use or switch off if unattended. What did surprise me was the bedroom TV equipment (including the old PVR and DVD player) this consumed 0.62kWh during a day and is only typically used for 1 to 2 hours in the evening. However, as the units are older ones the PVR manages 11W in standby (doing something useful) whereas the DVD player used 10W (doing nothing). As this is rarely used I unplugged it. The dining room HI-FI unit is so old it predates remote controls for the most part. The only bits with standby were the CD player and radio (which has not been used in years). These still managed 5W so I switched the unit off at the wall – a far simpler way of operating it. Lastly, I checked my son’s old CRT TV. This uses around 60W when in use and 6W on standby. However, to his credit, he switches this off at night and total use for a day came in at 0.195kWh.

There are other items that use power but I’m thinking that the tumble dryer is going to be the biggest gain. I’m still curious about the other items and particularly older entertainment units. I don’t believe in throwing things away just because they are old but there must be a cut-off point with some items whereby a new appliance will actually pay for itself quite quickly. The biggest part of my power bill is still the gas bill and this is tricky to reduce without major works on the house. I paid out extra to get the flat roof insulated when it blew off last year and this has paid dividends, if not in the gas bill then certainly that that part of the house is warmer – the bathroom in Winter is now bearable. I am now thinking that I may need to think that problem in reverse: rather than trying to stop heat escaping I may find it easier to prevent rooms from being over-heated in the first place. There are gadgets available which will allow rooms to have individual timed thermostats and that could well be the next best investment.