Posts tagged energy
Recently I added a smart power strip to the TV/Amplifier setup in the living room. My main aim was convenience – to make it easier to turn everything off all at once. But I also wanted to see how much power I could save by eliminating the parasitic power drain that a TV, amplifier and two DVD players have when in the ‘off’ state.
The power strip I bought is the one featured to the right here and to date I’m pretty happy with how it’s working. The power strip has one ‘blue’ outlet that senses when a single device goes on or off and then several ‘green’ outlets that switch accordingly. Initially I plugged the amplifier into the sensing output and everything else into the green outlets. That worked great and when the amplifier goes off so does the TV, the DVD player and the DVD changer. Since the amplifier is a Denon -CI model I can also control it remotely and since everything else switches on and off with it I can remotely shut down the whole stack from my home automation software.
The only problem with that approach is that in the ‘off’ mode the Denon -CI still consumes about 5W whereas the TV consumes 0W when off. The TV is one of the earliest HD TVs, a Panasonic Tau CRT TV so it’s fairly power hungry when on but it has a ‘real’ on/off switch so when it’s off there is no power draw at all. [Until recently the picture on that CRT beat nearly every flat panel TV on the market, but with recent LED LCD TVs I think I may finally be willing to part with it. It's old technology, but still an awesome HD picture.] So now I have to chose between remote power-off control and a 5W constant draw or no remote control and 0W consumption.
When I purchased the smart power strip I was concerned that it might itself have a phantom power drain equivalent to one of the other devices but it appears to be relatively harmless consuming hardly any current for itself.
The one adjustment you need to make on the smart power strip is to set the sensitivity so it can turn on and off at the right point.
Overall, definitely a recommended buy on this one.
I’m somewhat surprised to see how much effort and excitement Google and Microsoft are putting into the ability to show graphs of home energy consumption minute-by-minute from a smart meter. I’ve had that ability in my house for several years now (not directly measured but a close enough proxy based on knowing which devices are currently on or off). My conclusion after staring at the graph on and off for several years now is that it’s really not that interesting!
Here’s one of my 24 hour graphs showing the peak, minimum and average electricity consumption in five minute intervals during the day. Fascinating huh? So what are you going to do with it?
The fact of the matter is that you still need to take a shower and the fridge still needs to stay cool – those peaks really aren’t interesting. If you do want to see how much energy any device is using you can get one of the many Wattage Monitoring Products. They can come in handy in deciding whether to replace your television with a modern LED TV but they probably aren’t going to change the way you behave.
It turns out that the real problem here is the base-load rather than the occasional short-lived peak. Some of that base load is unavoidable but one of the top controllable loads is lights that stay on for hours at a time, so, in your quest to reduce energy consumption, start with them. Replacing them with compact fluorescents or LED lights is an obvious step, but not without drawbacks (lack of dimming, harsher white light, flickering, …). A better solution is to have a smart home; one that can turn lights off when people aren’t in a room, or can lower the brightness according to the time of day. That’s what my home automation system does and it has produced some fairly dramatic energy savings as a result: over the past 5 years it now uses 40% less electricity than it used to! Unfortunately most home automation systems aren’t smart enough to do this – they will happily plunge you into darkness because you sat still for too long in one room. After years of refinement (both software and hardware) my own system can now accurately assess which rooms are occupied and very rarely does it make a mistake that results in darkness when there should be light. As I mentioned earlier it also prolongs bulb life by running them at less than 100% saving more energy and dramatically reducing how often you need to go up a ladder to change those high-up lights.
This then is really the graph you want to pay attention to and it’s something you can make yourself using the utility bills you get every month. I also think that the energy companies could do more to promote green-envy: simply show people how much less energy their neighbors are using! Shame them into action. Rank them … “you are #1 in your street for energy conservation”. I know some places have started to do something like this but it needs to be widespread.
Over the years as I’ve advanced my home automation system I’ve gained a good picture as to how power is used within a home and number one on the list of energy hogs is home lighting. Maybe in a small house this would be different but in America houses tend to be large and they have lots of lights and those lights are left on for long periods of time.
In addition to replacing some light bulbs with compact fluorescents and some with LED lights (Cree LED’s only since I don’t like flickery-blue light) the house also strives to shut down the lights in any area of the home that’s not occupied. It aggressively shuts down lights in rooms that have had no motion in them for a while and if it detects someone leaving it looks for more opportunities to shut off lights sooner.
Another unexpected saving that you can make with home automation is to run your incandescent lights at less than 100% brightness. Since most home automation controlled light switches are dimmable it’s easy to set them to come on at 90% or less. Based on the time of day my house will use different lighting levels – just 20% if you head to the bathroom late at night, 60% early evening while there’s still natural light and 90% for ‘full-on’. Not only does this save energy but it prolongs the life of the light bulbs themselves dramatically. Couple with running at less than 100%, the soft-start that most smart light switches offer provides less thermal shock on the filament and it runs cooler. And since it takes energy to make light bulbs, and it’s tiresome to go around changing them all the time, this is one saving that pays multiple dividends.
So my home automation isn’t ever going to get to zero, but 40% reduction in electricity is still a lot better than nothing!