I have recently acquired an electricity usage meter off ebay and decided to measure the power consumption of some of my devices. For a device that costs just 15 SGD, it works wonderfully and can measure voltage, amperage and wattage. It is supposed to be able to calculate electricity cost once you input the cost/kWh but I prefer to calculate it manually instead of leaving it plugged in throughout the day. It is rated to a maximum wattage of 2900W so it should be safe for use on most small home appliances. For energy guzzlers such as air conditioners, washing machines or anything with a heating element, use at your own risk.
The current price of electricity in Singapore is 17.68 cents/kWh.
Readings I have obtained:
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One of the interesting observations was just how little power modern computers require. I own a relatively high end system with an i7 CPU and a GTX970 card but it consumes only 211W under load, scaling down efficiently to only 54W idle. It also consumes 3.5W even when switched off, I suspect this is due to the network card being set on a low power state to receive Wake On Lan packets. 3.5W is coincidentally the amount of power my quad core ARM server consumes when idling.
My headless server consumes only 38.9W at regular load, costing approximately 5.11 SGD in electricity costs per month. This puts to an end the long standing argument that Digital Ocean's 5 USD/month VPS is cheaper than running your own server. A VPS does have its benefits, it does not require a capital outlay of approximately 300 SGD in equipment and is easier to set up and scale up. However, running your own server allows you to have much more storage for all your media and backups. Since the server is on the local network, you have much better bandwidth and latency. An old laptop is perfect for using as a server, you get to save on hardware costs and it consumes little power.
The table below shows a comparison of the power consumption of other household devices and the electricity cost of running it for 100 hours. Through this episode, I am glad to know that my electronic devices are not significant contributors to the power bill.
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