400w MH to 250w MH - Big temperature difference?

[StirCrazy]

there will be a little bit of difference in power consumption, more if you go with the lumitec ballast, but realy not that much. as for heat, a little bit lower but I doubt you would even notice it.

as for bulbs, if you like the look of 20K, go with the SE radium 20K 250 watt bulbs.

Steve

[Borderjumper]

I have 2 tanks side by side of apx the same size. One is 400W and one is
250W. They both run about the same temp... which is like 82 today~

[fkshiu]

I think if you go from a 400W "HQI" down to a 250W electronic you will notice a difference in heat output because actual consumption will be halved from around 500W to 250W. However, if you're using, say, a 400W electronic ballast and go to a 250W HQI (M80) then you will hardly be using any less electricity and there will be no difference in heat.

When I went from magnetic 175W (M57) ballasts to 250W HQI (M80) my tank temps in the summer shot up quite a bit..

[Bryan]

I can tell you I noticed a big difference in heat output from my old Iwasaki 400watt vs 250 watt XM's. Remember if using a magnetic ballast, extra heat as well.

[Mrfish55]

I just upgraded from 250's to 400's and noticed quite an increase in the heat produced from the lights, doesn't affect the tank much as I have the fixture vented to the outdoors.

[Todd]

Originally Posted by fkshiu

I think if you go from a 400W "HQI" down to a 250W electronic you will notice a difference in heat output because actual consumption will be halved from around 500W to 250W. However, if you're using, say, a 400W electronic ballast and go to a 250W HQI (M80) then you will hardly be using any less electricity and there will be no difference in heat.

When I went from magnetic 175W (M57) ballasts to 250W HQI (M80) my tank temps in the summer shot up quite a bit..

I'd be going from "hqi" which I understand to be a magnetic ballast (correct?) to a electronic (digital) ballast. It looks like everyone has a 50 / 50 opionion of if this will result in a change in temperature. What about electicity usage - Can I just simply figure out how many kWh this will result in saving and find out my power savings that way? Or is it not quite so simple.

I figured it would be this: [(800 w - 500 w) / 1000] x 6 hours per day x 7 days a week x 52 = 655.2 kWh

This would mean a 54$ savings in one year in electricity (based on BC hydros teir two rate). Unless there is a even larger difference in the electricity savings due the different ballasts being more efficient.

Any thoughts on this?