Motion sensors
 

Hi everyone,

I have a question, is it energy efficient to use Motion sensors in rooms to detect if anyone is using it, and if not automatically turns off every electrical equipment.

Come to think of it the motion sensors also consume energy for it to run?

Would love to hear your thoughts on this one.

Good question. I could see doing that with lights, but not a tv. That would just bug me after a while to have to turn the tv back on every time I got up to pee or go for a snack. Actually it would bug me to have to turn the light back on as well.

Maybe if you could set the sensor to turn things off after a certain period of time.

I don't know, the more I think about it the more I think that it's useless unless you were to just put it into a bathroom or something for people who forget to turn the light off. It would also have to be more of a heat sensor then motion though. How often do you move while watching TV, or reading a book.

Its energy efficient if you are lazy (or just not paying any attention to energy usage, example: kids) and don't turn off the lights yourself. If you remember to turn things off when you leave a room then its not going to save you anything.

I don't think sensors would help very much for lighting, unless the lights were also controlled by a smart computer program.

Just using Off-the-shelf units will turn on the lights for a set minimum time cycle,
each time someone was in the room, even if it was only for a few seconds.

The other big problem I have with my automatic lights, if I'm not constantly moving around,
they go off, normally at the worst possible moment.

You would need what they call occupancy sensors. They use motion, sound, and some even use more to detect if someone is in the room.

I have two motion sensors in my house, they are the common ones that every big box store sells.
I have one in my garage so when I open up the door and walk in with my bike the light turns on, I can also see my garage from inside the house so if I see the light come on at night I know someone is in my garage! I also never have to worry about someone leaving the light on out there for hours and hours and it never comes on in the day time.
my other motion sensor light switch is in my entry way because the light switch is not near the door, I also often come in that door with groceries in my hands, for that room it's really nice to not have to fumble for a switch or take my shoes off in the dark, if you stop moving it doesn't always realize you are still there and the light turns off after 60 seconds.
Neither of these motion sensors work with CFL or LED bulbs, the LED never turns off and the CFL flickers on and off because the switch it's self draws around 2 watts in standby mode.

One other place that I've seen a motion sensor work really well was in a bath room hooked to the vent fan, it had it's on time dial cranked up to 10 minutes or so and every time you went in the bath room the fan came on, that bath room had a lot of repairs done due to moisture problems and this was part of the fix after the rot was taken care of, it was also in a rental so you couldn't rely on a well trained home owner.

I would like to try some occupancy sensor switches and see how they compare, my entry way is getting a washing machine hooked up soon, so a better sensor in there would be nice.

This is a tuff nut to crack. I use home automation and have kids. Sensing occupancy is difficult. I plan on putting flex sensors in the floor that isn't masonry and bed sensors but what about the basement slab? My kids are peaceful and calm but they sometimes forget to turn the lights off.

Old and forgetful..
 

Sometimes, I forget to turn off the lights.. But, I use these..

http://images.lowes.com/product/conv...01997859xl.jpg

At 7.5 watts, it's going to take a while to run up the bill.. :D

Being an ecorenovator is a state of mind. I mainly use incandescent bulbs because dimming is important to me, but I am vigilant about their on time. Often the houses I work in have already had an energy audit where all their bulbs have been replaced with CFL's and they are on all the time. "It's OK. There're CFL's".

Yeah, the previous owner of my house had the same mindset. "Oh, it only costs $5/mo to run those lights". They had the basement lights (3 - 14W CFLs and 1 - 20W tube florescent, so 60W total on) wired to be on all the time. In fact, one of the first changes to the house was to wire in a switch! $5 bucks a month to have lights on that you aren't even using 99% of the time.