Can and LED floodlight possibly be as bright as a real floodlight?

Compare lumens, no watts. Watts= enegy to produce lumens.

A reflector also makes a huge difference over a raw bulb. Type of reflector also makes a difference...a given area at a given distance from the light source will receive more light from a narrow beam reflector than from a wide beam reflector.

Yes. Spend $15 or more on a Lux Meter (photometer), measure the spot intensities, and see for yourself: I have one of these:

However, there's a problem. The total light output of an LED light is rated in lumens, not lux. Lux is just the intensity at a given point. Focus the beam, and you get a really high lux value. Spread it out into your floodlight, and the intensity is much less. Lumens is the total output, in all directions. The right way to measure that is with an integrating sphere: My way is much easier, but not terribly accurate. However, it will do nicely for comparisons. I recently threw together the procedure and posted it to the rec.bicycles.tech newsgroup. Cut-n-pasted:

1. Point light at the wall in a dark room at a distance of 1 meter. There's nothing sacred about the 1 meter distance. If 1 meter seems too close, just pick another distance.
2. Measure the spot diameter on the wall. If the light slowly fades away from the hot spot, just guess the half brightness points. If the spot is oval shaped, measure both the maximum and minimum diameters and calculate an average.
3. At the same 1 meter distance, use the Lux meter to measure the brightness. This is not really correct, since lumens is the total brightness, including the over spray. The brightness will also follow a Gaussian curve over the spot diameter.
4. Calculate the beam width in degrees. Dust off the long forgotten inverse trigonometric functions on your calculator: Beam_width_in_degrees = 2 * arctan (spot_radius/dist) where: spot_radius = 1/2 * spot diameter, in your favorite units of measure dist = distance between light and spot in same units of measure.
5. Using the values of lux, distance, and beamwidth, plug into one of the calculators at: to obtain lumens.

I would be interested in collecting results as I only have a few bicycle lights and flashlights suitable for testing. Please include measurements, maker, model, battery type, manufacturers rated lumens, and condition of battery (new, used, old, leaking, dead). So far:

Light spot_dia dist width bright calc mfg (cm) (cm) (deg) (lux) (lumens) (lumens)

There are other problems when comparing LED and incandescent brightness. The spectra is not the same. Therefore the perceived brightness will vary with the color temperature. Most lights have some amount of over-spray outside of the spot area. The lux meter will not capture these, resulting in some error. The intensity across the spot is not uniform but tends to follow a Gaussian curve. Some lights have a very hot spot in the middle, and then just fade out towards the edges. Do your best and see how close to the rated lumens you get.

Good luck.

Can't help you out on the question. But, I installed 21 Lithonia LED can lights throughout my place. They cost a bit more than other brands, but been real pleased with the lights/looks. Had to have 1 replacement afterwards, and they sent me 2 with no questions asked.

Thanks all.

It turns out this time that the HD price is the same as Amazon, maybe less, but I just went to the store** and it wasn't in stock. I'm in no hurry. I'll ship it to the store, or maybe to my house (over 50 dollars shipping is free)

BTW, it got quite a few complaints about strobing or breaking within a year on the Amazon site (and also on the HD site that was hard to read) but overall still scored a 4.8 out of 5 (which should really be 3.8 out of 4)

WRT lights for the front door, they had Zenith/Heath that had low lighting for 2, 4 hours or all night, and high lighting if the motion sensor saw something. And some of the lights by Hampton Bay (house brand?) had sensor that could control 325 watts, even though the most that could be used in the light was 100. The other 225 could be elsewhere, powered by the extra red wire. Lighting has gotten more complicated since last I looked.

Well, someone -- thank you -- reminded me to look at lumens

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I wasn't sure if this was per head, so I looked at the 3 head version, and it said "Each head contains (3) 5339K high performance LEDs which maintain 1,719 lumen output "

Different K value, but I guess they are giving the total, as they should be.

And then I looked at 100 watt incandescent. About 1500 lumen times 2 =

So since I really can't judge how bright 1222 lumens from LEDs will be, I don't kow whether to buy that 1222 for $117 or 1719 for $150.

Or stay with incandescent for much less and hope they don't burn out so fast if I get a good brand that doesn't turn on with the wind. I almost never go there at night so if they don't turn on in the wind, they'll burn less than 5 hours a year 2000 hour lifespan will be 400 years. Ugh.

Hi, Out kitchen had 75W pot flood lights. All been replaced with bright white (color temp. 5000K,60W equivalent Philips bulbs dimmable, it is as bright as ole bulbs. No problem. Most of bulbs in the house is now all LEDs. Could see some difference in the power bill. They run always cool. Good in summer time.

I didn't do so well. Through LED lighting transplants and juggling some electronics, I managed to drop my monthly electric burn from an average of 375 kw-hr in 2008 to about 315 kw-hr average in 2014. See spreadsheet and graph at: Note the trend lines. While my electricity consumption was going down, PG&E was busy raising their rates and juggling the tiers. The result was despite the lower consumption, I am still paying roughly the same per month. Grumble.

Some analysis with a clamp on ammeter and kill-a-watt meter showed that the bulk of my electric usage is the electric water heater. They don't make an LED water heater and solar is not an option in a forest. I'm looking into flash water heaters, but it looks like it would take years to recover the initial investment. A wood burning water heater using a hot tub as a hot water tank is a possibility, but doesn't work well with my convenience lifestyle.

That's genius. If it were me I'd put my energy into making it even easier. But lowering it to the ground is by far the easiest way. Have you ever w ondered how they change bulbs in those high mast freeway lights? They don' t climb, the fixture lowers on a cable.

I only have one LED lamp in the house. I use it every day and it's been ab out four years, but one data point doesn't say much. I've only changed two outdoor floods in 6 years. I bought fluorescent replacements but am still waiting for one to fail so I can try them.

I recently replaced a 95W flood light on the garage with an LED. It is a whiter light and looks to be much brighter. I'm going to replace the other bulb soon too. I really like it. The fixture is mounted about 15 feet high and give plenty of light in the driveway.

Can an LED floodlight possibly be as bright as a real floodlight?

The fixture will be mounted about 24 feet above the ground so it has to be bright.

Snip

I have a one Cree LED porch light that senses movement on our front porch. Amazing how bright and coverage it has. Reflector of course. WW

Typical use here is 750 kw so overall, you are doing well.

Hi, We consume around 1000KWh per month. Down from ~1300KWh. I think our 4 person electric Sauna sucks lot of juice even running on 220V.

The general answer is yes. My church has some flood lights at the end of the gymnasium, and also in the chapel. The facilities guys put in LED floods, which work fine. They say the bulbs cost twenty to thirty dollars each.

I'd test the bulb on the ground at night before taking it that far in the air. Rig up a lamp cord.

If the unit was 110 V, do you think the cost would be different?

Hint: Watt is a unit of work. You pay for watts.

. Christopher A. Young Learn about Jesus

On Sun, 12 Oct 2014 20:26:36 -0700, Jeff Liebermann wrote as underneath :

Air source or ground source Heatpump might be the answer for your water heating by electricity - worth a look? C+

Yes, you can buy LED lighting units which make your standard 100W incandescent flood bulb look like a dim candle. Readily-available off-the-shelf units which replace a big sodium vapor lamp are rated a

Thanks. I didn't know a heat pump water heater existed. As I skim thruogh the online literature, I read that heat pumps are good for room heating/cooling, but not so good for heating water. Some larger ones use a water tank for a heat conducting fluid, but the water is not meant to be consumed. There are heat pump water heaters: but those are geothermal, not air source. Looking at prices, such water heaters start at about $1,000 plus installation. I haven't run the numbers yet, but I suspect the expected savings in electricity would not cover the cost of the installed system within its expected lifetime (or mine). I'll do some more reading and see where it leads. Thanks again.

My solution to the hot water problem is a nuclear powered water heater. Just a lump of some isotope that produces heat while breaking down. Fukushima should have plenty of the stuff worth mining. The nuclear water heater would be lead lined and buried for safety. Water temperature would be regulated by adding or removing radioactive pellets. There are also some safety issues that will need to be addressed.

Actually, this is all academic as we're having a water shortage in California and unless it rains this winter, there isn't going to be any water to heat. Meanwhile, I'll probably just do a better job of insulating the tank and hot water pipes and wait patiently for the rain and a nuclear water heater.

Actyally you pay for energy, kWh ( kilowatthours) not for power ( as watt is).

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