Metal Halide vs T5

[Beng]

I've read a number of articles online about the differences between T5 lights and Metal Halide lamps. For the past 5 years i've run a 250W metal halide off an electronic ballast during the winter. It keeps them actively growing while all my other trees are wintering outside.

That said the electric has been higher then I expected this year esp... and i'm looking into possibly replacing it with a T5.

I'm wondering how many T5 bulbs one would need to replicate the light output of one 250W 6500K metal halide bulb and also if the growth from the T5 bulbs is equivalent to that of metal halides? I get great results from my metal halide but T5's are so cheap now that with the cost of electric it may be a better way to go.

Ben

 

[davetree]

A regular T5 setup will take a lot of bulbs to replace your halide lamp. A high output T5 costs more money but you get what you pay for and it will perform better. You will not be able to go cheaper and get better or more light. You will get about the same results from 250 watts of HO T5 as you will with your halide. A 250 watt lamp run 12 hours per day would cost me about 25 cents per day to run at .08/kwh. About $8 per month.

 

[Beng]

Really I thought they were more energy efficient with similar output? My 250w metal halide costs at least double to triple that to run 8 hours a day, about 30 dollars a month. My only reason for switching would be if I could get the same quality light and save on energy costs. I saw a 4 foot 4 tube light at http://www.homeharvest.com/indoor-l...designer-t5-fluorescent-lighting-systems.html that was reasonable at 160. If that is 8 dollars per 2 foot bulb per month though then the cost would be the same or more then the metal halide.....

Ben

 

[mat]

kilowatts x billing rate ($/kwh) x hours of operation = your cost. doesn't matter what sort of lamp it is. You may factor in lamp replacement costs over time, but that wasn't asked above.

Here's a basic calculator:

http://www.handymath.com/cgi-bin/electric.cgi?submit=Entry

As far as how to compare the efficiency of the two sources, here's a chart that has some good numbers. It isn't specifically about lighting plants, but the light fixtures act the same whether hanging in a warehouse or in your garage.

http://relightdepot.com/news/lighti...h-bay-compared-to-400w-metal-halide-high-bay/

Obviously there are other differences as well, but I thought the above info might help the discussion.

 

[Poink88]

Let us not equate Watts with lumens. More efficient light produce more lumens per watt.

 

[davetree]

You are only using 2 kwh per day with your setup, which is 60 kwh per month. If your electric rates are double mine it is still less than $10/ month. How are you getting to $30 ?

 

[mat]

Let us not equate Watts with lumens. More efficient light produce more lumens per watt.

Of course. The chart in my second link addresses lumens.

Edit: including lumens per watts (efficacy)

 

[davetree]

There is not that much difference in lumens per watt between halide and HO T5 lights. From my experience the T5 setup will spread the light out more (good for lots of small trees) while the halide will provide more intense light to a smaller area.

 

[Beng]

I'm in the NYC area so our electric is higher then probably almost anywhere else. I'm not sure the exact breakdown cents per KW but i know it costs around 30 per month to run it. My ballast is a lumatek 400W dimmable type which has settings for 250w 400w lights. Perhaps it is using more then 250W of electric since it has the ability to run 400w bulbs as well.

Ben

 

[GrimLore]

I find being not to far from NYC that rates are a bit high here as well and honest if I call a rep they normally can lead me in the proper direction on consumption... Rates and Carriers vary a LOT thoughout this vast country.

 

[davetree]

I checked, some of your rates in the New York City area are actually lower than mine. Your light even at 400 watts is not consuming that much juice.

 

[Poink88]

Here is the power rate here at Austin, TX
View attachment 29909

If my math is right, 400 watts running 16 hours a day at the highest tier of our power rate scale comes to about $18.50/month or roughly $20.00 per month as averaged between summer and winter rates.

 

[davetree]

He's running 8 hours per day, even at 400 watts is about 30 cents per day to run, or less than $10/month.

 

[Poink88]

He's running 8 hours per day, even at 400 watts is about 30 cents per day to run, or less than $10/month.

Yep, half what I calculated (16 hrs) at the highest rates in my area. We also factored 400 watts vs 250.

 

[GrimLore]

I must say if I do run lights they are on a timer for 16 hours - nothing more or less and in my humble opinion should be a standard rule of thumb.

 

[mat]

Beng, your $/kwh rate should be on your power bill. You don't have to guess at it. How do you know it's costing $30/month?

There may be additional considerations. For example, if you're air conditioning a room that you're also heating up with light fixtures, it will take some extra kw's for your AC to compensate, especially if you have a bunch of lights. This should be significantly less than the power used by your fixtures though.

 

[Redwood Ryan]

I must say if I do run lights they are on a timer for 16 hours - nothing more or less and in my humble opinion should be a standard rule of thumb.

I run mine for 14 hours. Works very well.

 

[Beng]

Thanks all, something else must be eating the power bill up this winter i guess... Not sure what though since we have water heaters here.

 

[Bonsai Nut]

Beng.... T5 and MH will use about the same amount of electricity to generate the same lumens. You should check out LED's if you want higher efficiency.

 

[GrimLore]

Thanks all, something else must be eating the power bill up this winter i guess... Not sure what though since we have water heaters here.

We knocked off over a 100kw per month Usage replacing kitchen appliances, If you have Hot Water Baseboard Heat and a cold Winter the Unit that pumps the water throughout the building works a LOT. Could be normal if it has been cold but could also mean it needs to be looked at.