Archive for the ‘Incandescent’ Category

« Older Entries

California Lighting, Final Thoughts

Wednesday, July 22nd, 2009

All in all, the California Title 24 legislation is pretty progressive. With regard to lighting, it is really focused toward making you think about the lighting in your home. You really have two primary approaches toward lighting your living space: either committing fully to fluorescent lighting or using dimmers throughout your home for energy savings. The state is also clearly looking forward to LED lighting, but frankly the industry isn’t ready to support that yet. However, the rate of growth is so strong it will only be a few more years before that changes.

If you commit to fluorescent lighting remember to consider the color temperature and color rendering index of each lamp. Right now people aren’t accustomed to the way everything appears under fluorescents, but I think in a generation the quality of fluorescent lighting will become our new “normal.” With technological advances the fluorescent and LED sources will improve and either the manufacturers will make them more like natural light or (more likely) we’ll just grow to accept the spectral profiles of those sources.

However, if you aren’t ready to make that leap yet you can use dimming systems. I think everyone should use dimming in their homes even if they don’t care at all about energy efficiency, since I believe the quality of life benefits shouldn’t be ignored.

And instead of just using local dimmers, hopefully this will stimulate the use of wider-ranging lighting systems. System that enable you to program lighting for entire rooms rather than just adjusting each circuit. There are countless options out there so don’t feel limited by the adoption of more stringent energy efficiency standards as they progress from the west coast eastward.

Tags: , , , ,
Posted in Dimming, Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent | No Comments »

California Lighting, Special Rooms

Monday, July 20th, 2009

Special Rooms-Kitchen:

The biggest and most complex part of the lighting section of California’s Title 24 is with regard to kitchen lighting. You are allowed to use a combination of high and low efficacy fixtures in the kitchen because the state considers the visual requirements in the kitchen to be so much more complex than in the rest of the home.

You can use low efficacy fixtures (only in the kitchen) with a combined wattage not to exceed the combined wattage of high efficacy fixtures also in the kitchen. That means if you install 150 watts of high efficacy fluorescent lighting in the kitchen you are also allowed to install up to 150 watts of low efficacy incandescent, halogen, or low-voltage lighting.

Lighting built into cabinets is excluded because it has its own rules, but those built-ins must only light the inside of the cabinet. Lighting attached to the outside of the cabinets does not count as cabinet lighting, but must be included as part of the kitchen wattage calculation. The same goes if you have lighting inside your cabinet but it is designed to light surfaces outside of the cabinet. That is, you can’t install one of the low-voltage striplights that has little MR-16 attachments to point onto your counters to try to get around the kitchen wattage restrictions.

The high efficacy and low efficacy lighting in the kitchen must be controlled separately. (Actually, that is true everywhere, but since you can’t use low efficacy fixtures unless they are dimmed the distinction is a little pointless. You can’t combine different source types on a dimmer, so you couldn’t dim both incandescent and fluorescent fixtures on one control. I guess the only way to mix would be if all of them were on a vacancy sensor, but you shouldn’t be mixing fixture types in any room in which you want to use vacancy sensors anyway.)

To calculate the wattage of the low efficacy fixtures you must use the highest wattage allowed by the fixture. That means you can’t “save” by putting a smaller light bulb in the fixture, say a 60 watt bulb in a fixture that can take up to 100 watts. If you are using low-voltage fixtures you have to use the input wattage of the transformer, which is most likely going to be higher than the wattage of the lamp or lamps.

If you want to use track lighting in your kitchen there are a number of different ways to calculate the wattage against your allowance, but the easiest is just to use 45 watts per foot of track, unless the actual lamping is greater. Yep, a three foot section of track over your island counts as 135 watts, even if you just put two dinky 20 watt pendants on the track. If instead you put three 75 watt incandescent lamps you would have to use the higher combined wattage of 225.

The state has also figured you might try to get around the restriction by running your wiring to boxes and then not hooking up any fixture until after the inspection is complete. So each electrical box either covered by a blank plate or where there isn’t any electrical equipment hooked up counts as 180 watts of low efficacy power toward your allotment. Actually, this is often done innocently when you are going to install a ceiling fan but it hasn’t been picked out yet. The electrician runs the wires to a box that will someday support the fan for you, but he may be done and off the job before the final fan selection is made if you are going to install the fan yourself.

Finally, if you have a kitchen that seamlessly merges into your breakfast nook or any other room you have to be careful with the control wiring. If it looks like a single room the nook will be counted as part of the kitchen unless the lights are controlled by different switches/dimmers/whatever.

Other rooms:

The restrictions for bathrooms, attached and detached garages, laundry rooms,closets, and utility rooms are tighter than for the rest of the home. All the fixtures in all of these rooms must be high efficacy. There are only two exceptions: one, you can use permanently installed low efficacy fixtures if the control is a vacancy sensor; or two, if the closet is less than 70 square feet you can have permanently installed low efficacy fixtures without a vacancy sensor.

Notably missing from the exceptions for these rooms is the exception for using dimmers. As a personal point, I am sorry this is the case since I think that it is pretty important to dim the lights in the bathroom. See my post on dimmers in the bathroom for the reasons why. And if you have dimmed incandescent or halogen fixtures throughout your home I think it is poor design to use dimmed fluorescent in the bathroom.

Tags: , , , ,
Posted in Dimming, Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent | No Comments »

California Lighting, Overview

Thursday, July 16th, 2009

California has recently adopted energy efficiency standards that have a huge impact upon lighting. And since California has been leading the country in energy efficiency standards I thought I’d write up a quick summary of what homeowners ought to know about the changes to residential lighting since it is just a matter of time before similar rules spread to the rest of the country. Note that there are a couple adoption dates that we haven’t reached yet, so the entire Title 24 code isn’t in effect as of right now, but we may as well look to the future.

First of all, the new rules apply to all new residences and other projects that require a permit, so chances are you’re going to have to comply. Portable lighting, such as table and floor lamps, are not covered by the changes. However, all permanent lighting is covered and that basically includes anything attached to a surface. So you can’t stick a lighting track on the ceiling but control it by a cord plugged into an outlet. Lighting installed in furniture like cabinets or bath vanities is included. The big exception to this is lighting that is built into appliances, such as microwaves, refrigerators or stove exhaust hoods.

The idea is to divide lighting fixtures into high efficacy and low efficacy groups. You can install all the high efficacy fixtures you want anywhere you want. (Interestingly, to divide the fixtures into high and low efficacy the rules use just the lamp efficiency, rather than the actual fixture efficacy. Remember the efficiency/efficacy post?) To determine if a fixture is high efficacy it must comply with the following lumens per watt limits.

  • If the fixture’s lamp is 5 watts or less, it must get at least 30 lumens per watt.
  • If the fixture’s lamp is up to 15 watts, it must get at least 40 lumens per watt.
  • If the fixture’s lamp is up to 40 watts, it must get at least 50 lumens per watt.
  • If the fixture’s lamp is over 40 watts, it must get at least 60 lumens per watt.

(However, the method to determine the lumens per watt of LED fixtures has some restrictions so you can’t use the LPW of the LED module. You have to use the input power of the LED driver, but then it must also comply with the same LPW restrictions as above. You do NOT have to take the ballast for fluorescent lamps into account.)

Anything that doesn’t meet the above LPW restrictions is considered a low efficacy fixture.

In addition, there are some things that will automatically classify fixtures as a low efficacy fixture, the most important being that anything with a screw base socket is considered low efficacy. That means all fixtures using the medium or candelabra size socket that all our fixtures in our homes have been using for decades. There are some other things but the screw base socket is the most important. There is an exception for HID lamps with screw base sockets, and a huge section regarding the GU-24 base, but you probably won’t have to be concerned with those details.

Now, once you know what is high efficacy or low efficacy you can figure out what you can install in your home. There is a complex exception for the kitchen, but the basic rule of thumb is that you can only use high efficacy fixtures in your home.

Now, there are exceptions for most of your living areas:

  1. Low efficacy fixtures may be used if the circuit is controlled by a “vacancy sensor.” This is not the same as an occupancy sensor! A vacancy sensor is defined by the state as a control that can only be turned on manually and will automatically turn itself off after a preset time of 30 minutes or less unless it detects that the room is occupied or if the control is turned off manually. This explicitly excludes controls that turn on automatically, which is how occupancy sensors typically work. Also, if the control has a switch or something that allows you to choose if the turn on method is manual or automatic, it does not count.
  2. Low efficacy fixtures may be used if the circuit is controlled by a dimmer. The dimmer can be one that has several steps instead of a continuous sliding range, however, the dimmer must reduce the energy use by at least 65% at its lowest setting. That means that two-level switches with three settings (off, 1/2,  and full on) do not count. Three-level switches which have four settings (off, 1/3, 2/3, and full on) do count. Also, if the dimming circuit can be controlled from multiple locations it must be impossible to bypass the dimmer. The alternate locations can either be remote dimmers or switches that turn the lights either off or to the dimmed level only.

There are exceptions and additions, most notably in the kitchen. However, it’s fairly involved so I’ll address them in the next post.

Tags: , , , ,
Posted in Dimming, Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent | No Comments »

Efficiency Comparison Pitfalls: Systems

Friday, July 10th, 2009

Another pitfall with comparing lamp source efficiency is the entire system’s efficacy.

With incandescent and halogen sources, the wattage on the label is pretty much what you get.

  • Technical info, you don’t have to read or understand this: the “what you see is what you get” assumes that the voltage matches. That is, a normal 100 watt light bulb will consume 100 watts at normal household voltage of around 120V. If the voltage is increased, the wattage increases, and if the voltage is decreased the watts consumed also decreases. Some manufacturers use this effect to create longer life and energy savings bulbs; for example, GE sells a 100 watt 130 volt lamp (3,000 hour life) which is labeled for 120 volt use as using 89 watts (8,300 hour life). Of course, the light output also decreases, and it decreases faster than the energy savings: losing 25% of the light output while only saving 11% of the electricity consumption.

Discharge sources, like fluorescent, require some form of control gear to regulate the electricity being consumed. The wattage label on the bulb is not the wattage which will actually be used in the system because the lamps can’t regulate their energy consumption themselves. They require a ballast to do that for them.

Since the ballast is what actually controls the wattage consumption, you have to calculate the efficiency of the system using both the lamp (for the lumen output) and the ballast. Professionals use the term efficacy instead of efficiency to remind themselves that they are dealing with the multipart system rather than just a lamp. So if you compare the efficiency of an incandescent bulb to a fluorescent replacement, you have to make the comparison against the system’s efficacy, not the lamp efficiency.

For the self-ballasted compact fluorescents you pick up at Wal-Mart the comparison is still fairly easy, since the ballast is included as a part of the lamp and the wattage listed on the box is for the ballast. In that regard, you can compare a regular light bulb off the shelf with the CFL next to it. However, if you live somewhere like California, where they have outlawed the use of medium screw based sockets in new construction (emphasis on new), you can’t use a self-ballasted CFL anymore.

Instead, you have to look at the efficacy of the lamp/ballast combination. Different ballasts will have all kinds of different ratings and properties that make reviewing them mind-numbing for the average person who just wants a light bulb. The take away is that the lamp ballast efficacy will be different than the lamp source efficiency. Usually it is less, although sometimes a system can have better efficacy than its lamp’s efficiency.

  • Technical info, you don’t have to read or understand this: Ballasts affect the lumen output out the lamps they control separate from the age issue I discussed previously. The affect is known as the “ballast factor,” which is the ratio of what the ballast does to the lamp it is powering versus the fictitious “perfect laboratory ballast” which is used to give the lumens shown on the lamp box. The number is a percentage (real output divided by “perfect” output) and written to two decimals (0.77 or 1.53). You will see ballast factors greater than 100%, accompanied by a wattage higher than the wattage listed for the lamp alone. To determine actual lumen output, you have to multiple the listed lumens by the ballast factor. This new lumen value is what you use to determine the efficacy of the system, along with the ballast’s wattage for that lamp. One ballast may have different ballast factors for different lamps, which will be listed. For easy comparison of ballast factors among different ballasts, there is also a “ballast efficacy factor,” which is the ballast factor divided by the input watts. The higher this BEF the more efficient the lamp/ballast combination, so you can compare ballasts for the same lamp that may have different wattage usage.

An example to demonstrate that you have to look at both the lamp and ballast:

I’m using a 4′ long linear T8 lamp, like you see in a 2′x4′ office fixture that is recessed in a grid ceiling made up of 2′x2′ tiles. To be specific, it is a GE F32T8/SPX35/ECO, which provides 2800 (mean) lumens for 32 watts. My first ballast option is going to be a GE “Residential Grade ProLine” ballast (GE232-120-RES). The lumen output for one lamp is 2,772 (mean lamp lumen times the ballast factor). The system wattage is 32, so the efficacy of the system is 86.6 LPW. I then substitute the “Residential Grade” for a regular “ProLine” ballast (GE232-120-N). The lumen output for one lamp is now 2,632. The system wattage is 36, so the efficacy is now 73.1 LPW. I want to try one more ballast and I choose the “UltraMax Instant Start Multi-Voltage High-Efficiency” because the name sounds cool and highly efficient (GE132MAX-L/ULTRA) The lumen output is now 2,156. The system wattage is 25, so the efficacy is 86.2 LPW.

To choose my ballast, and because I don’t care about how much each one costs for this example, I discount the “ProLine” ballast since it gives me similar output to the “Residential Grade” ballast with less efficacy. Now, I have to choose between the “Residential Grade ProLine” and the “UltraMax.” They have similar efficacies, so I have to choose which I want based on the lumen output. What I haven’t told you yet is that I’m replacing a surface mounted fixture in my home that uses two 75 watt bulbs. The lumen output of the existing fixture that I am trying to match is 2,340, which falls between the 2,772 of the “Residential Grade” ballast and the 2,156 of the “UltraMax.” Rather than decide based on the efficacy or the wattage of each individual ballast I have to select the ballast based on the light output. I decide that I always though the room was a little bit too dark anyway and so I choose the “Residential Grade” ballast. Now, I’ve got a touch more light than before while saving about 75% of the energy, dropping from 150 watts down to just 32!

PS: I’ve written this using fluorescent lighting as the examples, but the same is true for all the gas discharge sources, like metal-halide, high-pressure sodium, etc. High-pressure sodium is an especially efficient light source, although it suffers from all those color temperature and color rendition problems discussed in previous posts.

Tags: , , , ,
Posted in Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent | 2 Comments »

How Do I Know What’s Efficient?

Wednesday, July 8th, 2009

I have fielded a variety of questions from people trying to figure out what kind of lighting is more or less efficient than others. Many people understand that lower wattage is better, from a consumption view, but they don’t necessarily feel like they are comparing apples to apples when they try to compare incandescent to compact fluorescent or LED.

The way to determine efficiency of any given source is to figure out how much light you get for the amount of power used. Using the lowest wattage source may not be the most efficient approach if it doesn’t give you enough light and you end up adding more. The lighting industry uses a measurement called Lumens per Watt, or LPW. We take the total lumen output of the source divided by the wattage so we can make direct comparisons.

For example: a regular 100 watt light bulb for a table lamp, with clear glass so you can see through it, will provide about 1,750 lumens (it will say this somewhere on the box). Since it uses 100 watts, you divide 1,750 by 100 and figure out its efficiency is 17.5 LPW. Now you can compare that to a compact fluorescent replacement lamp (with a screw in base for your lamp) and find that it provides about 1,700 lumens for only 26 watts. The CFL lamp has an efficiency of a bit over 65 LPW. Therefore, we can say that the CFL lamp is almost 4 times as efficient as the incandescent.

To provide some general guidance I’ll type up a quick list of some sources and their LPW ranges:

  • Standard incandescent bulbs range from around 4 to 20 LPW
  • Tungsten-halogen bulbs range from around 18 to 22 LPW
  • Low wattage compact fluorescents range from around 20 to 60 LPW.
  • High wattage compact fluorescents range from around 50 to 80 LPW.
  • Linear fluorescents range from around 65 to 95 LPW.
  • LEDs range from around 5 to 40 LPW, although there is so much development of LED sources right now this range is likely to change quickly.

As with everything I write about lighting, there are some caveats. I’ll discuss a few of those in upcoming posts.

Tags: , , ,
Posted in Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent, New Tech | 1 Comment »

Color Temperature Basics: What is It?

Wednesday, July 1st, 2009

Color temperature refers to a “black-body radiator.” This is a theoretical object (as in, it doesn’t really exist but we pretend it does because we find that useful) that will absorb all electromagnetic radiation cast upon it; it will reflect or transfer none. Visible light is a small portion of electromagnetic radiation, which you can think of as the stuff coming from the sun that provides light and heat.

When a black body radiator is heated it begins to glow. There’s a cool java applet on the Olympus Microscopy Resource Center website that demonstrates this idea with a picture of a horseshoe. At the lower range it begins by glowing red. Then as it gets hotter it goes through yellow and white phases, eventually shifting into the very bright blue-white range. At any particular color, we refer to the temperature of the blackbody as the “color temperature.” (A note on that java tutorial, the temperature indicated on the scale refers to the tips of the horseshoe. The other colors move down the horseshoe to show that the tips are being heated and the bottom is cooler than the tip. The temperature does not relate to all the colors shown in the image.) The temperature is on the Kelvin scale, which is the same as celsius plus 273. That is, -273˚C is 0 K, 0˚C is 273 K, and 100˚C is 373 K.

For lighting, it is easier to refer to the temperature generating a color than trying to describe the color itself, which changes slowly and is not really part of our language of color. If you are looking at that java applet from Olympus, try to describe the difference between the color of the horseshoe tips at 2700K, 3000K, and 3200K. You’ll quickly realize why referring to a color temperature is easier.

A bit of confusing terminology, however, is that we refer to red the red side as “warm” and the blue side as “cool.” This is based on our traditional color associations of red and blue. It can be confusing because the bluer tint comes as you increase the temperature. Hence, you may hear people refer to “raising” the color temperature to “cool” the light source.

The filament of a regular incandescent lamp is not a true black-body, but it does go through the same color process as it is heated. That’s why when you put a regular lightbulb on a dimmer it shifts toward the red as you dim it down: it’s the horseshoe in reverse. Therefore, if you’re looking at incandescent lightbulbs color temperature isn’t a very useful metric. Regular and halogen lamps at full power usually end up around 2700K to 3050K, and that can be changed by adjusting the voltage. The real purpose of discussing color temperature is for fluorescent lamps, which I’ll get to tomorrow.

Tags: , , , ,
Posted in Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent | No Comments »

Dimmers Throughout the Home

Friday, June 19th, 2009

Lastly, all the others places in the home are when most people start with dimmers instead of ending with them. The dining room, living room, family room, etc. are good places to create the warm family home most people enjoy. Those are often the first places people think to install dimmers since they think of those areas as more “public.” I agree, and since those rooms get used so much they are great places to install dimmers. But if you can’t afford or want to buy dimmers for every room in your house you should leave these rooms until the next round of dimmers and just focus on the rooms discussed in the last few posts.

Tags: ,
Posted in Dimming, General Knowledge, Homeowner Tips, Incandescent | No Comments »

Dimmers in the Kitchen

Thursday, June 18th, 2009

The kitchen is an odd sort of place when it comes to dimming. You need to have lots of light for preparing meals, so it would seem to be a place you could skip. However, the kitchen is also a place where many people tend to congregate. To that end, your dimmer will receive much more of a workout, but you’ll end up finding you use it all the time. It becomes a more comfortable gathering place when dimmed, and you’ll find yourself only cracking it up to full to prepare a big meal. Most of the time it will be dimmed down some.

Note that some newer homes have fluorescent lights installed in the kitchen to really pump up the light levels for cooking. If you have a fluorescent light in the kitchen, you’ll need to refer to my postings about fluorescent dimming, which I haven’t written yet. Be on the lookout.

Tags: , , ,
Posted in Dimming, Fluorescent (and CFL), General Knowledge, Homeowner Tips, Incandescent | No Comments »

The Sad News

Friday, June 5th, 2009

Although the two tips posted a couple days ago are quick and easy to do, they aren’t going to provide you with the savings you’ll get from other, more comprehensive methods. Also, your room won’t be as bright as before. The amount of light created by a regular light bulb is directly related to how much power it is using, so reducing the power will reduce the light. However, most of the time a reduction of around 8% won’t be noticeable. However, if you’re using them in a single lamp fixture that is the only source in an entire room you might notice the difference. Or, you may not want to change the lamp in your reading light, but it is a start.

You also won’t get anywhere close to the savings you would get from switching to compact fluorescents. However, you also don’t have to make the lifestyle changes associated with switching to compact fluorescents either. Using compact fluorescent properly involves understanding color and daytime versus nighttime usage. I believe that rampant misapplication of CFL lamps is the reason they haven’t caught on as quickly as their proponents would like. However, in a future blog I’ll discuss ways you can use CFLs properly to improve your life.

Tags: , ,
Posted in Homeowner Tips, Incandescent | No Comments »

The Reasons for the Savings

Thursday, June 4th, 2009

Yesterday I posted two tips for saving power. The reasons these methods work are a bit technical, but I’ll post the short version just for interest.

  1. Wattage is proportional to the voltage supplied to the lamp and the resistance within the lamp. The power company supplies your voltage, and the lamp manufacturer supplies the resistance. Homes in the US are nominally supposed to have 120 volts supplied at outlets and in built-in lights, although the actual voltage will vary for all kinds of technical reasons. You’ll also see labels listing voltages as a range, such as 110-120V, or as an intermediate number, such as 115V. When you use a lamp that is designed for 130V the manufacturer has decreased the resistance slightly in order to provide the labeled wattage assuming 130V. If you give that lamp less voltage, the wattage is also reduced because the resistance has already been reduced. How much is saved? I’ll round it off to about 8%. Also, the bulb will last longer.
  2. The reason dimmers work at saving electricity is basically the same idea. If you run a cheap dimmer at full, it isn’t really giving you full power. The dimmer creates a cap that is less than full. So, instead of 100%, full power is only 94%. That number is only an example, the actual number will differ based on all kinds of things. Even if you never use the dimmer to dim the lights, they will still be using less energy. Although, if you do dim the lights, you’ll get even more savings. Dimming a light 50% will save 40% power and can make a light bulb last 10 times as long as normal!

Tags: , ,
Posted in General Knowledge, Homeowner Tips, Incandescent | No Comments »

« Older Entries