Some of my twitter friends had a conversation about saving money on lighting the other day. Energy use is a topic that I’ve delved into a bit previously and I’d like to share some resources and thoughts that might be useful to my friends and to other people.
“Every big helps”
People often have the mentality that “every little helps”. They think switching off a phone charger here or a lightbulb there is important and fret about that. David MacKay, a Cambridge professor and advisor to the UK government has coined the phrase “every big helps” to help restore a sense of perspective. The point is focusing on the big things – the stuff that actually accounts for most power usage – has a much bigger impact on energy use, and therefore on energy bills and on the environment.
Watch this fantastic five minute video to hear him explain:
So what is big?
When it comes to electricity use, you can get a rough idea of how much electricity is used by different items in your home from this table from the US Dept of Energy:
These are obviously ballpark figures. Every model of appliance is a bit different, and every person and family has a different pattern of usage. All the same, it gives an important rough idea of what is likely to be a big contributor to your electricity bill, and what is probably pretty small.
For example one low-energy light-bulb on for three or so hours a day might only account for $2 of your annual bill, while your fridge-freezer could easily account for $60.
As one of my friends pointed out, the table shows a desktop PC using only 75W. A gaming PC running state-of-the-art games on max resolution could easily be using four times that much or more. So a heavy gaming habit could easily pwn all the lightbulbs in your house put together in terms of energy use.
The table at least shows you how to think about energy use, and back-of-the-envelope math is enough to get a ballpark idea of what is likely to be most important for you. Just estimate and add up…
- power used when on * hours on
- power used on standy * hours on standby
This info is for electricity use only, but that’s what sparked this post.
Some probably good things to do
What’s most impactful to do is going to vary from person to person, but some things are likely to apply in a lot of cases.
- If you’re not already using low-energy lightbulbs, it’s pretty much a no-brainer these days. It might not make the biggest impact but it’s easy and cheap to do.
- Heating and cooling are big on energy use. That means turning the heating or aircon down slightly could save more than all that running around worrying about lightbulbs.
- “Heating and cooling” includes stuff like dishwashers, washing machines, fridges etc. When it’s time to change one of those items, getting a more efficient one is probably going to be a great idea. Also using the less power hungry programs, like washing at a lower temperature.
- Insulation to stop your heat vanishing off into the night air is very good, but putting all that in can be expensive. Sometimes there are grants to help with that though.
The Bigger Picture
Want to know more about energy use, sustainable energy, what it’s going to take to avoid dangerous climate change etc? Here are some great resources…
Sustainable Energy – without the hot air – a website and ebook from David MacKay
The site has a section of videos, which might be a quicker and more enjoyable way to get the main ideas:
Sustainable Energy – Without the Hot Air with David MacKay (one hour talk at Harvard)
David MacKay – How the Laws of Physics Constrain Our Sustainable Energy Options (18 minute TEDx talk)