Another envirolite question

[LJ]

Hi all

Anyone any idea of the lifespan for envirolites?? Roughly??

Thanks

Heather

[An D Smith]

Hi Heather

I use the Envirolights and I was told their life-span is around 10 000 hours, or a couple of years of use.

Cheers

Andy

[LJ]

Hi Andy

Many thanks for reply. Hmmm.........16 hrs a day.........should last about 20 months roughly then unless I've worked it out work wrong which is highly likely!!

Atleast I sort of know when I need to get a spare in by now

Heather

[Rob-Rah]

How do you know when they need replacing though? Mine look bright, and the plants are seeming to do ok.

Do you just throw away lights that appear to be working fine just on the offchance that the spectrum is not what it used to be?

[-=Joel=-]

Im sure your plants will let you know when they need changing :)

[venusflytrapman]

I used the calculator, and you will get roughly 625 days out of it. About a year and a half, you were right.

[mobile]

How do you know when they need replacing though? Mine look bright, and the plants are seeming to do ok.

Do you just throw away lights that appear to be working fine just on the offchance that the spectrum is not what it used to be?

The spectrum is unlikely to change much but the intensity will decrease over time, that's true of all fluorescent lamps. It hard for the human eye to perceive the drop in intensity as it's a gradual process over a relatively long period of time so you don't really notice, your plants will though.

[mobile]

Hi Heather

I use the Envirolights and I was told their life-span is around 10 000 hours, or a couple of years of use.

Cheers

Andy

Confirmation of 10,000 hours: http://www.plugandgrow.co.uk/files/envirol...ications_en.pdf

[LJ]

Thanks for the confirmation mobile, good to know.

Heather

[Martin]

The spectrum is unlikely to change much but the intensity will decrease over time, that's true of all fluorescent lamps. It hard for the human eye to perceive the drop in intensity as it's a gradual process over a relatively long period of time so you don't really notice, your plants will though.

here is a summery on the decrease on light intensity of flourescent tubes (in German):

http://hereinspaziert.de/Lampen/Leuchtstoff.htm

I not sure if "envirolight" are similar to those

also for metal halide:

http://hereinspaziert.de/Lampen/HQI.htm

Quite interesting imho.

(My current setup with three 70W 942 HCI lights + electronic ballast has a life span of 15,000h, but after 5,000h they only give 70% of the lumens :'-( and I assume that they should be replaced then.

At ~18€ a lamp this adds a significant amount to the already very high cost for electricity.)

Martin

Edited March 19, 2008 by Martin

[mobile]

(My current setup with three 70W 942 HCI lights + electronic ballast has a life span of 15,000h, but after 5,000h they only give 70% of the lumens :'-( and I assume that they should be replaced then.

If the output from your tubes is calculated by the minimum lumen requirements for your plants then when it drops your plants may not receive all the light required, but if you over specified the output, i.e. more lumens that required you can allow for a drop down the the actual requirements of your plants.

An output drop over time is typical of all florescent lights but the human eye may not notice it.

Edited March 19, 2008 by mobile

[Martin]

If the output from your tubes is calculated by the minimum lumen requirements for your plants then when it drops your plants may not receive all the light required, but if you over specified the output, i.e. more lumens that required you can allow for a drop down the the actual requirements of your plants.

An output drop over time is typical of all florescent lights but the human eye may not notice it.

In my case it's some mathematics and some "green thinking".

3 * 77W (70W + electronic ballast) * 12h * 365d = 1,012kWh

At 20ct/kWh I have to pay an electricity bill of 200,- Euro each year for those plant lights

(this is more electricity than I need for everything else together!)

The output, when new, is 3 * 6,000lm = 18,000 lumen.

After 365*12h = 4,380h it should be ~75% (the 942 type is worse than the 830 type)

On an average calculation that makes ~87% of 18,000lm = 15,750lm

If I would use the bulbs for three years the average output would be ~ 65%, which gives 11,700lm from three lights or 15,600lm from four lights.

Now the calculation:

a) Replacing 3 lights every year costs 200,- Euro electricity + 50,- Euro for new bulbs each year = 250,- Euro/a

b) Replacing 4 lights every 3 years costs 267,- Euro electricity + 22,- Euro per year for new bulbs = 290,- Euro /a

I would also need 33% more electricity in case b), which will create 33% more CO2...

(the higher initial cost for a 4 light setup vs. a 3 light setup aren't even included)

If I would have done my mathematics _before_ buying the lamps I would have thought about those 150W 942 HCI lights.

They have a higher lm/W output when new (~90lm/W vs. 78lm/W) , they decrease a lot slower during usage than their 70W brethren (85% after 5,000h vs. 75% after 5,000h) and it would not only be possible to replace them less often but you also have to replace fewer bulbs (which cost the same as the 70W bulbs).

c) 2x 155W*12h*365d = 1358KWh, which costs ~270€/a, bulb cost would be 11€/a = 281€/a

makes 2*14.000lm*80% = 22.400lm

That's 34% more electricity and CO2 :'-( , only 12% higher cost :-/, but also 42% more light! :-))

As always, someone is wiser afterwards :-/

Martin

Edited March 19, 2008 by Martin