Submitted by: Michael Dawson (firstname.lastname@example.org)
I constantly try to find ways to make our home more energy efficient, but the benefits of these changes aren’t easily measured. There’s a large information gap between incremental improvements and the monthly arrival of the electricity bill. I wanted to know: how can I track the effects of our specific activities when our home has so many appliances? When do we use the most electricity? Or can we even approach the ultimate level of granularity: which appliances and devices use the most energy? I’ve found the answer to these questions are now easily available thanks to a couple of inexpensive solutions.
Two handy measuring tools provided the answers to my problem.
1. SmartMeters. Cost: $0.0
Like many Lafayette residents, my house was recently given new digital SmartMeters to replace the older electrical and gas “spinning dials”. PG&E began installing these new meters as part of a larger push to upgrade the electrical grid and also provide easier meter collection. While SmartMeters have been controversial, I encountered no hurdles.
By entering the PG&E website and selecting my electrical account, I was able to download my usage history by the hour. Here’s a sample chart of energy consumption by hour starting at 12am and ending a 11pm over a period of six days:
Notice the two large humps — one large morning hump peaking at 9:00am and a smaller but longer hump again at night peaking around 8:00pm. It didn’t take long to determine the first spike. In the morning, our 2 HP pool pump cycles and is our home’s largest energy hog…obviously this hog needs to go on a diet. I’ll be installing a two-speed pump which will dramatically smooth the spike in usage and in fact pay for itself in one year.
For the evening increase, the particular energy culprits are harder to determine: lights, computers, stereos, ovens, a microwave, recharging phones, etc. are all used between the hours of 5pm and 8pm. Additionally, there is a small but steady charge that occurs throughout the night from the plugged in devices which are off but still drawing current. These are often called “phantom charges”. To sort it all out, I had to turn to another device which allowed me to measure energy usage, outlet by outlet.
2. Kill-A-Watt: Available online for $15 – $20.
“Kill-A-Watt” comes in a small package, but packs a wallop of information. (If this looks familiar, you may remember that we’ve featured this greatest little device before.) Basically, you plug this device in an outlet, and plug any appliance in the Kill-a-Watt. You’re then able to track watts consumed — familiar to anyone replacing light bulbs — and also kilowatts per hour. kW per hour is handy for measuring variable electricity usage such as a computer, microwave, or television.
I plugged the Kill-A-Watt in each electrical gadget around the house and entered the data in a spreadsheet. My measurements ranged from 2 watts for a bathroom nightlight up to a whopping 1500 watts for an electric radiator heater set to high. I’ll be thinking twice before using that again! The biggest surprise was the phantom charges of the flat-screen TV, DVR, and receiver which consumed 50 watts while turned completely OFF. This explained some of the steady overnight charge on the graph above. I was also surprised to find our older desktop PC consumed 160 watts compared to our newer Mac laptop at only 27 watts.
Benefit & Payback
With this information, I was able to measure the benefits of specific changes:
- My desktop computer (160 watts) is now set to hibernate after 10 minutes instead of an hour. Monthly savings: $6.12
- Recirculation hot water pump (90 watts) is now on a timer to run 4 hrs a day instead continuously. Monthly savings: $21.60
- Electric radiator heater is no longer used for spare bedroom guests. Savings: $14.40 per day during visits.
- TV, DRV, and receiver are now on an SmartStrip Surge Protector* to eliminate phantom charge. Monthly savings: $13.50.
* The SmartStrip (available in local hardware stores for about $35) was a discovery during the recent Tomorrowland booth at the 2010 Lafayette Art and Wine Festival. This gadget acts as a surge protector, but also lets you shut off any current draw while devices are turned off. Handy!
All in all, I found an incredible $83 of savings per month by making simple changes:
- Reduce phantom charges with surge protectors and timers
- Unplugging unused devices
- Set computers to hibernate as quickly as possible
- Discontinue using older equipment and heaters
I’ll also save at least $150 per month by swapping out that pool pump energy hog.
PG&E Smart Meters
Smart Strip Surge Protector
Available of local hardware stores