I just bought the Trans Am from "Smokey and the Bandit" and I'm supercharging it! "Hold on to your ass, Fred"

Just kidding.

I've installed several of the new compact fluorescent light bulbs. They are curly like a pig's tail and supposedly use less energy. One suggestion: Don't get the "Outside light" version as it's kind of harsh.

Anyway, upon first installing them, the color was noticeably brighter (again, the outside light version) but as they've been in for a while - they seem darker. I'm guessing since they are fluorescent - that they flicker a bit. At night now, they almost seem dim. Am I seeing flicker - like a very slow refresh rate? I see brightness, but its almost as if i see the prolonged and frequent dark times... I'd like to use these more often, but not if I have to squint.

Anyone see what I see, or have a brand and wattage that seems OK?

Thanks,

Marshall

Try a different brand. I went through this. Not all CF bulbs are alike. What I have now is very good and have been consistent for 2 years so far. It just took a bit of trial and error.

Marc

Yes they vary in quality. I bought all new ones for the house a few months ago at home depot and they work great so far. They were just some cheap generics but still strong and no flicker visible.

Oh, but those are the style for recessed cans, they have a standard looking outer glass covering the curly part so you can't tell it's florescent just looking from any distance.

Still probably the same manufacturer of their standard generics. Give them a shot they're cheap in 4 or 6 packs.

Troy

I've been curious about these too. I think sometimes they seem really dim, it's weird. Other times they don't seem so dim. I don't know anything about them though.

I've got them recently too (to make up for my Hummer ;) ). Actually I got them because my power bill will go up 1.5x for the Green power (wind and solar) if I don't reduce usage.

I too found them hit and miss. Some are a nice mellow yellow. Some are a harsh cross of red and blue...ick. One doesn't start reliably...grrr.

Don't get the cheapest ones....

Well, I'll try a different brand and style, but who has been pleased with a particular type? It sounds stupid, bit the brand I have seems OK during the day but dim at night. I know, pile on...

OK, the model I have is N Vision... Anyone?

It may not be comparable, but I'll take a look in the box of CF bulb packets (they all have incandescents in them now...what do I do with them? They still work..).

Let you know what brand I'm happy with.

The 18w ones are REALLY BRIGHT I've found.

The ones I got at home depot are branded "Commercial Electric". 4 pack 14w 8000 hour. Brighter than the spotlights they replaced. Take a minute to warm up of course, pretty dim for the minute or so it takes to warm up. Package says they have some quickstart technology whatever that means, but still there is that minute wait.

I have about 20 of them installed, no problems, huge savings...

Troy

Quick start is nice, they light up with out flickering like the older ones used too.

I like the fact that they are dim at first, gives my eyes a chance to adjust to the light.

There is no real downside to these CF anymore. As soon as everyone gets used to them and starts to use them we will be saving a ton of energy.

Deron.

I'm curious about how they compare with LEDs, and when we'll start seeing LED based bulbs? My understanding is that LEDs are pretty darn efficient as well, I don't know how they compare to flourescents though.

http://www.theledlight.com/120-VAC-LEDbulbs.html

Ok, the ones I like are GE, the ones I don't are Mirabella. But, the one that failed almost straight away was GE.

I don't know if you can get them in the US, but that's my experience anyway.

The ones I got at home depot are branded "Commercial Electric". 4 pack 14w 8000 hour. Brighter than the spotlights they replaced. Take a minute to warm up of course, pretty dim for the minute or so it takes to warm up. Package says they have some quickstart technology whatever that means, but still there is that minute wait.

I have about 20 of them installed, no problems, huge savings...

Troy

The Home Depot bulbs do work quite well.

Buy the "warm light" version. I find the light indistinguishable from incandescents other than the short warm up period.

I even replaced the 500w bulb in the pool light with a forty something watt fluorescent. Not quite as bright, but plenty bright enough.

They also last much longer in the garage door opener. Vibration seems not to affect them.

Thanks everyone - the ones I have are from Home Depot. I probably should try a different color - as these are too white.

Also, what I am seeing is that they are really bright withing 3' of the bulb, but kind of dim 6' away and greater. Almost like they cannot fill the area past a certain point. I don't see any warmup period, though... So everyone is happy with the light from the GE brand (if they work).

I didn't know they came in a traditional "bulb" type of cover - these seem to distribute light the best?

The flickering probably means it contains a magnetic ballast as opposed to an electronic one. Magnetic ballasts will flicker @ 60 Hz, electronics will vary based on the size of lamp, but are generally in the KHz range - too fast for the eye to detect. Magnetic ballasts are also less efficient.

Most CFL's will come designed with a color temp of 2700K - 3000K, which is considered "warm white," and closest to an incandescent lamp. 4100K would be considered "cool white" and is often used in offices & retail.

LED's are getting close.. All of the "EXIT" signs we stock now are LED lit, and some store-front signage is starting to change over too. At a recent event here the Sylvania rep was showing an LED recessed can light with a "warm white" light color.. Looked very promising..

Most of mine are made by "Lights of America" sold at home depot. They are all electronic ballast and don't flicker. ALL except the circlelights are dimmer when they first turn on. Also, they take longer to reach full brightness when it's very cold. But my regular straight tubes are even worse when it's cold.

I really like the twisted tube bulbs. In my shop they give me 150watts of light for ... 29?

Have various types all over the house now. Failure rate is very low. Came a LOOOONG way from the early bulbs.

Marc

I like the compact fluorescent bulbs made by Technical Consumer Products (TCPI.com), which are available from several on-line vendors. I've ordered from 1000bulbs.com. Web links at bottom of this message. I think the TCPI bulbs are brighter and have better color rendering (closer to incandescents) than many other brands, also have been very reliable, with no flickering. I prefer the 2700 K to 3500 K ("warm" to "slightly warm") color temperatures, which are closest in appearance to standard or halogen incandescents.

Besides the common spiral type, TCPI makes bulbs with the spirals enclosed in an outer bulb shaped like a standard incandescent, globe, or reflector flood; these are best for "open" style lamps or fixtures, because the bare spirals are uncomfortably bright to look at directly. They also make three-way and dimmable compact fluorescents.

TCPI product literature states "specialized glass coating, tri-phosphor mix and lead-free glass provides better lumens and lumen maintenance over life of the bulb". The claim "better lumens" means brighter (more visible light output) than competing products, "better lumen maintenance" means that the brightness decreases more slowly over some long operation time like 10,000 hours.

http://www.tcpi.com/lighting-solutions/compact-fluorescent-lamps.aspx
(can download full or select catalog from this page)

http://www.1000bulbs.com/category.php?category=14

I'm curious about how they compare with LEDs, and when we'll start seeing LED based bulbs? My understanding is that LEDs are pretty darn efficient as well, I don't know how they compare to flourescents though.

Currently, fluorescent bulbs, whether cylinder or compact types for general lighting applications, or CCFLs used for backlighting in LCD or rear projection HDTVs, are still the champions for energy efficiency; i.e, highest electrical to optical conversion ratio (lumens/watt). However fluorescent lighting is a mature technology, with maybe five decades of R&D, and is unlikely to improve noticeably in the future. High-brightness LEDs are a much newer technology, and still improving rapidly. It's likely (I believe almost certain) that the best LEDs will surpass fluorescent bulbs in energy efficiency within several years.

Overview of solid-state lighting (LEDs), Sandia National Laboratory
http://www.sandia.gov/lighting/XlightingoverviewFAQ.htm

Press release, Jan. 23, 2007
"Philips Lumileds shatters 350 mA performance records
with 115 lm/Watt LED"
http://lumileds.com/newsandevents/releases/PR64.pdf

Take a minute to warm up of course, pretty dim for the minute or so it takes to warm up.

This is what I hate about these. Are there any that don't do this? I don't leave lights on when leaving rooms, so flipping on these in a dark hallway is horrible. I've pretty much given up on them and am going to try to find some LED ones. They use even less energy and last WAAAAAAY longer.

Dave

What I am going to say about these CFLs will sure sound REALLY weird....

I know of someone who installed a LOT of these CFLs from Costco....you know the cheap ones. He has a 5500 sq ft house. So there are a huge number of them.

Here is the weird thing....on one particular circuit.....the bathroom....one of the vanity's lights would "burn out" the moment we switch them on. After losing 2 or 3 of these CFLs...he just left that vanity light alone.

I recently installed some recessed lights in the same circuit and installed some PAR30 halogens. All was good until they also literally exploded the next day!! :eek: Actually they exploded internally .

Anyway, uopn checking the whole circuit I could not find anything amiss. So on a hunch I removed all the CFLs from that circuit and replaced them with cheap light bulbs.
VIOLA...everything is OK now :confused:

Are there ghosts in that circuit or what?

The only thing I can think of is that "maybe" by removing those burnt out CFLs...I removed something which may cause a surge?

Or maybe it has something to do with power factor? I read a LONG time back that installing a huge number of flourescent lamps requires use of PF correction capacitors. Maybe that was old school but still spplies to these new fangled CFLS


Oh by the way....these CFLs light VERY dim in sub-zero temperatures. I lived in NH and had such a CFL on my porch...it took a long time to reach full brightness.

We have a bunch of CFLs in our house, but I have been wondering if it really makes sense.

These things take a lot more materials-wise than a (single) traditional bulb. That's supposed to be mitigated by their longer life. What concerns me more is that they contain mercury and other nasty chemicals, instead of glass/copper/ceramic/tungsten/etc in a traditional bulb.

But consider: the main reason people buy CFLs is to save energy. When do you use them? Duh, when it's dark. When is it dark? Primarily in the winter. Which is when, in most parts of the world, you are heating your house.

OK, so incandescent lights are "less efficient." That means less of the input energy is converted to light. What happens to the rest of the energy? All, or nearly all of it, is emitted as HEAT.

So: if it's cold and you're heating your house, incandescent bulbs inside your house are basically 100% efficient! Not all of the energy is used to create light, but ALL of it is used productively. The heat generated by the bulb reduces the energy you use to heat your house.

Does that make sense?

If that's true, then does it make sense to buy the CFLs with their toxic components?

(If you need lights at any time when you run your air conditioning, then obviously this argument is not valid. CFLs make great sense in that situation. But if you mainly need the lights during heating season...)

Gary

Can you dim a LED light? I would like to try them in the kitchen with all of my recessed lighting.

This is what I hate about these. Are there any that don't do this? I don't leave lights on when leaving rooms, so flipping on these in a dark hallway is horrible. I've pretty much given up on them and am going to try to find some LED ones. They use even less energy and last WAAAAAAY longer.

Dave

It is my understanding that the "Long Life" ones have a warm up time of 3x (about 180 sec) the "regular life" ones.

I've pretty much given up on them and am going to try to find some LED ones. They use even less energy and last WAAAAAAY longer.


They use less energy, and produce far less light then a fluorescent.

Any know if there are dimable CFL's????

Any know if there are dimable CFL's????

Yes there are, but they have to be specifically made to work with dimmers. The package tells you if it can be used with a dimmer or not.

Dave

Perfect..... that is what has been stoping me from buying. Most of my circuits are on dimmers. I hate bright lights.....! Thanks

I'd use them everywhere if I could but my wife hates the color of light they put off. I can see her point, we've tried different brands w/o WAF. I am only allowed to put them in selected areas of the house. Pick your battles.

LED's might fix this, but need to be cheaper, since I am more financially than enviromentally motivated.

Dave, did you try the different color temps? I have "daylight" and I really don't like the light color. Have you tried the soft white versions? Oooh, you can also get them with a traditional shell over the spiral so they look ike traditional light bulbs.

Just checked the prices of LEDs... yow!

Perfect..... that is what has been stoping me from buying. Most of my circuits are on dimmers. I hate bright lights.....! Thanks

Couple issues with dimmables...

most dimmable CFLs only go down to about 30% before they drop to off.
One issue this presents is that all lamps on the same circuit may not cut at the same time. Sometimes as others drop, the change to the circuit can cause one of the others to come back on... makes for a bit of a light show.
Have heard of buzzing issues on some dimmables.
Also, they are generally shorter life than standard.

We've tried a few different ones. I guess we'll keep trying over the next couple years. The ones that look like regular bulbs is an interesting, potentially sneaky thought.

Gary

It depends on what you are heating your house with. Gas is alot cheaper then electricty, so heat from the light bulb costs more then gas heat. Also the heat is high up (except for the radiant heat) where it does not help out much. And of course like you point out you do not want them heating up the house in summer.

Some bulbs make more sense in some situations then others. If I have a light in the hall where it is turned on for brief periods, I use a regular bulb. When you want to see yourself in a mirror, you want to look good, not yellow or green tinted. I would not go overboard with the CF bulbs, use them on the lights you leave on for extended periods, it's cheaper to use standard bulbs where they are on only for brief periods.

Deron.

Deron.

Yeah, that's what I figured. Electric isn't the cheapest way to heat, but still... people probably aren't saving as much energy/$$ with their CFLs as they think.

I agree with you Deron, I place the CFLs carefully. In my office, where it might be on for hours and colors aren't critical. In my kids' rooms, where they constantly forget to turn off the lights. Tried them in the kitchen but my wife nixed that. (Even though she almost never goes in there, I'm the cook in the family! :D)

We put low voltage halogen lighting (dimmable) all over the kitchen. I'd have to agree, kitchen is no place for CF.

Marc

Why not in the kitchen? It's code here in San Diego that 50% of the lighting in the kitchen has to be fluoresent. I put the CF in my ceiling cans and did not notice and differance in light color.

Deron.

Yes, but we have everything on dimmers. But I DO use CF's everywhere else in the house.

Marc

I've had no problem with the philips brand ones, they come on instantly, no warmup as such and are available in different colour temps. I have had one DOA in the 10 years I have been using them and I just took it back and exchanged it. We prefer the warmer colour, the blue/white ones feel like a morgue to me.

The philips ones seem to just work, around 18 watts for rooms where I have to do fine detail work (nice and bright), between 11w and 14w in the other rooms and 6w in the bedside lamps and the verandah/front door key light.

I saw the dimmable ones at Mitre 10 last week (Home depot style store) but haven't tried them.
I haven't bought a tungsten globe in 10 years or som and never missed them, but steer clear of cheap chinese ones (mirabella et al) they seem to be crapulent and dimmer. I had no trouble with GE, but have only used them occasionally over the years.

I put LED dimmable downlights into a guys HT room recently and they seemed OK for that application but not for ambient lighting a large room.

BTW if you are on electric hot water, turn it down a few degrees, it stops scalding and saves a fortune.

The biggest savings came when I fitted an LCD screen (jumbo calculator style screen, not a monitor) in the loungeroom that gives you a live update on how much electricity you are using in $$ and kW at the press of a button. Watching it tick over certainly makes you better at turning stuff off. The CFs made a big drop in out power consumption probably partially because I am a bit of a night owl.

I put a CFL in my kitchen. It's the equivalent of a 100W incandecent bulb. My only gripe with it is the somewhat slow start-up time. Aside from that, it's nice to know that I'm saving some energy and some money. It's too bad that the bulbs I got won't work in my 3-way floor lamps. Maybe they have special CFLs for 3-way lamps? Ah well, a dimmed incandecent light sets a nice warm mood. It will be very cool when LED light technology matures more and can be used in regular light sockets to save even more energy. I looked for such lights on the market now but the brightness is still pretty low, aside from the kind of lights used on radio towers.

Thanks for everyone's input. I ended up installing CFL throughout the house except for a few places. I initially got a couple from Home Depot (N.Vision, I think by Phillips) but they were the 5500K "daylight" version. I didn't really like the look.

Today I went back to the homer and got the same brand but in "Soft White" and they look fine. They do take a minute to warm up, but that's no biggie for me.

Mike, I did see a 3 way version, and I think it was at HD, although I also went to Lowe's.

I also have one further question. I know you are not supposed to expose a CRT lens to sunlight. Would a CFL hurt it?

I'm late to this discussion, but have what I think is a valid question; have always been a fan of old-school flouro tubes, but was taught/told that they take as much energy to lite off as they burn in 3 hours. So - actually less energy efficient for on-off usage.

Do cfls have the same problem - i.e., does it take more energy to turn one on, or have the engineers somehow gotten around that problem?

They do consume a larger amount of energy to start than a tungsten globe, but not significantly so with the newer electronic starters. I think it is about 3 times the normal running load during startup, so you only have to have the bulb on for a few seconds before you outrun a tungsten lamp, after that you are using 70% less power.

I like the philips ones because they also have ultra low mercury content, some people have claimed that the mercury content is a reason not to use CFs, but anywhere where coal powerstations provide the bulk of the power they end up reducing the total mercury entering the environment. The largest amounts of mercury entering the environment come from coal fired power stations.

Mercury in CFL vs incandecent click here: http://en.wikipedia.org/wiki/Image:CFL_bulb_mercury_use_environment.svg#file

That may not be with the lowest mercury CLF either.

Also from wikipedia: High-quality driver electronics can prolong the life of the burners by preheating the electrodes to prevent damage from rapid expansion. High-quality drivers require high-quality components. The best CFL manufacturers (including Osram, Philips, General Electric, Luxlite) produce CFLs that can last 15,000 hours. Such lifetimes require highly automated and controlled manufacturing.

I've found the german made Osram to be of the highest quality. The Dulux El Longlife models have a 15k hour life and a 500k switching cycle life. You can get them in sizes 3-30W and in warm white, cool white or daylight colours. No real excuse to use them everywhere but perhaps a reading lamp (where I prefer those little halogens I think they are...).

I'm late to this discussion, but have what I think is a valid question; have always been a fan of old-school flouro tubes, but was taught/told that they take as much energy to lite off as they burn in 3 hours. So - actually less energy efficient for on-off usage.

Do cfls have the same problem - i.e., does it take more energy to turn one on, or have the engineers somehow gotten around that problem?

Yes, but they are still more efficient in on/off use because the burst of energy they take is only equivalent to something like 30 seconds usage. So, if you are going to leave the room for more than 30 seconds, it is cheaper to turn them off then back on.

Dave

There was a Mythbuster epsiode not too long ago where I think they showed that the on/off thing wasnt true.


also here is an interesting article...

California may ban conventional lightbulbs by 2012 (http://today.reuters.com/news/articlenews.aspx?type=scienceNews&storyid=2007-01-31T020531Z_01_N30344683_RTRUKOC_0_US-ENERGY-CALIFORNIA-LIGHTBULBS.xml&src=rss&rpc=22)

Yes, but they are still more efficient in on/off use because the burst of energy they take is only equivalent to something like 30 seconds usage. So, if you are going to leave the room for more than 30 seconds, it is cheaper to turn them off then back on.

Dave

cool - thanks. 30 sec I can handle. 2-3 hrs I couldn't. Simple as that.

fs - would have to see that mythbusters, and doc to believe it. I thought I'd seen documentation to back it up on 4' and 8' tubes. Could be wrong. :confused:

I found a recap (http://www.televizzle.org/2007/01/16/20000_foot_fall.php) of the show...

First up is getting a bunch of light bulbs, and that's just what Grant, Kari and Tory do. They then set the bulbs up and test to see how much power they are actually using during one hour. Then they test to see how much they use when you turn them on. It turns out that they don't use much at all. In fact, they use so little power when you turn them on, it is virtually impossible for you to save money by leaving them on when you leave the room.

Compact fluorescent bulbs (swirls) are so efficient that it only takes .01 seconds of running to recoup the money "spent" during startup. So if it takes you longer than a tenth of a second to leave the room and get a cup of coffee, turn it off! A standard incandescent bulb takes about two-and-a-half times that, but it's still a lot less time than it takes most of us. The longest payback is for a fluorescent tube, but even then it's only 23 seconds. Generally speaking, if you're not in the room, turn it off and you'll save money. Leaving a light on simply does not save electricity (or, more importantly, money). Busted.

The longest payback is for a fluorescent tube, but even then it's only 23 seconds.

I was off by 7 seconds! Oh well.

Dave

Generally speaking, if you're not in the room, turn it off and you'll save money. Leaving a light on simply does not save electricity (or, more importantly, money). Busted.
I have no doubt turning it off, even for a minute, saves money **at the point of use**. But any electronics guy can tell you the turn-on shock is the cause of most failures for thermal devices like bulbs. (Think when incandescents burn out. Probably >95% of the time it's when you turn them on.) So are you saving a few watts, but killing the lifespan of your bulb? (Which of course takes energy to make and replace!)

When CFLs were newer, they always said on/off cycles were the killer, and lots of ons/offs would dramatically shorten the bulb lifetime. I understand the newer ones are supposed to be able to handle 100k's of cycles, which is good. Wonder about the incandescents?

I use true D6500K CFL lights in my HT, I love them, cuts down on heat, nice daylight light ;)

one word of warning, if you want to use IR remotes in a room with CFL's be prepared to pull your hair out, because it simply will not work, IR does not function correctly in a room with compact flourescent light, inteference prohibits it and causes horrid performance, I took this oppurtunity to go RF in my HT with my URC MX3000, but IR receiver dealers like Xantech make CFL immune IR receivers

-Gary

because it simply will not work

Blanket statement.

You can get IR filters for your gear that work with compact flourescents. If you use an IR extension system, you can get a CF-compatible receiver or use said filter on the receiver.

Weird, I've never had a problem?

I have never had a problem with CFLs and infrared remotes though I know other who have. So you may or may not have problems. I have used CFLs for over 10 years and never had a problem.

One thing you almost never see mentioned about CFLs though is they give off more UV than an incandescent bulbs. This is not a problem in most instances but some high end and much antique furniture (original finish) has photochemically reactive stains that in my personal experience have faded from exposure to the UV from CFL light bulbs. In one instance the table (of a pair) with the CFL lamp faded noticeably while the one with incandescents did not. For that reason I won't use CFLs for lights that directly illuminate "valuable" (whether monetary or sentimental reasons) artwork.

If you use an IR extension system, you can get a CF-compatible receiver or use said filter on the receiver.

ah? did I not say that :confused:

the filters merely cut down the range by large and unacceptable amounts, you need CFL receivers made for this very purpose

just the way it is, it may not be wacky 100%, you may have CFL and IR works fine, but 1 button pressed missed out of 1000 is enough to send me packin' ;)

Plasma adds to this also, I think Niles makes the best IR stuff, they have IR receivers for severe extreme CFL and Plasma enviornments that have good range

of course I am being picky about all this, but a remote that randomly misses codes won't work for me at all, even if it is 99% accurate, macros are vital to me :)

-Gary

I use true D6500K CFL lights in my HT, I love them, cuts down on heat, nice daylight light ;)

one word of warning, if you want to use IR remotes in a room with CFL's be prepared to pull your hair out, because it simply will not work, IR does not function correctly in a room with compact flourescent light, inteference prohibits it and causes horrid performance, I took this oppurtunity to go RF in my HT with my URC MX3000, but IR receiver dealers like Xantech make CFL immune IR receivers

-Gary


What brand/model CF are you using that has D6500K? I'd like some of those.

Marc

The biggest savings came when I fitted an LCD screen (jumbo calculator style screen, not a monitor) in the loungeroom that gives you a live update on how much electricity you are using in $$ and kW at the press of a button. Watching it tick over certainly makes you better at turning stuff off. The CFs made a big drop in out power consumption probably partially because I am a bit of a night owl.

That sounds cool! Where''d you get it?

SC

I got mine in Australia, but there is a US website.
http://www.centameter.us/

http://www.abc.net.au/newinventors/txt/s1076405.htm gives some info, and here is a blogger who has pretty much the same experience as me with it.

http://blogs.asman-it.com.au/dasman/index.php/20060401/centameter-monitoring-your-home-energy-consumption
http://www.centameter.com.au/images/smlfeaturescent.jpg

Good thread started here.

I have been looking into CF bulbs since starting to read here and am going to start in our kitchen which has 13 recessed 60 watt bulbs in it that are on quite a lot because it is a central gathering place.

Not knowing what bulbs to start with I stopped by HD yesterday and picked up the brand n:vision they have here that look like indoor recessed bulbs but are CF.
They offered two varieties. Soft white and Bright white. Both were 14 watt which the package says is equal to a 65 watt bulb. I bought one of each to test the colors.

I noticed that the bright white was much cooler in temp to the soft white which appeared to have a color temp similiar to the 65 watt incandescent bulbs we currently use. The bright white also appeared to be a "brighter" light (it would be being cooler) but it looked a bit harsh when compared to the soft white.
This morning I got out my colorimeter and measured the color temps of each.

Soft White CF - 2600 deg K

Bright White CF - 3500 deg K

65W incandescent - 2500 deg K

The Soft light also appeared to take a bit to come up to full brightness whereas the Bright light seemed to be at full brightness right away (or at least that was the impression I had).

Reading at Lightbulbs direct they say "A color temperature of 2700–3600 K is generally recommended for most indoor general and task lighting applications." So both of these bulbs fall into that catagory but I am leaning towards the warmer temps for my application because the cooler temps remind me of a doctors office. I may also go up on the wattage to 18 or so to put out a bit more light.

Terry

CFL's are nice way to cut down on energy. My problem with them is yellowing as they age.
But if you want truly save energy insulate your house. Most of the heat losses are from the roof and doors and windows. Add insolation in attic and bring it up to a foot.
If you have old doors and windows.. use masking tape to seal all the cracks around the openings for winters. It is cheap, easy to do and can be taken off at the end of cold season. Takes one hour to do 10 windows and 10 minutes to take them off.

We don't have winters any more down here :(

I've just ordered one of those centameter units that dok posted. I reckon I'll save enough to pay for it within a year.