Probably not much savings to be had with lights, you’re kinda low on light intensity with the two 400’s. Even with super high end leds you need 700-800 watts to hit ideal canopy intensity.
I would be looking closely at your bill though. Two 400’s isn’t costing you $300/month. A 1000 watt hps costs me about $1.20 per day to run for 12 hours.
I was thinking something along these lines, but couldn’t articulate it. Maybe it’s a combination of several things that could save you the most. Could you slow down your fans? Maybe veg under less hours of light per day, like 16/8 vs 18/6? The heater is probably what’s killing you, honestly. It’s probably consuming more by itself than everything else combined. If you can use your home’s HVAC to ‘tune’ the lung room, you may be able to eliminate the heater. Just thinking out loud (in print, anyway), hopefully it helps. 
3-260 for 5x5
3 would make sense too. I’d personally go with two. I wouldn’t pay that much to cover the other 7 sq ft. 2 of them would cover 18 of the 25 sq ft. That’s just me tho.
Hello, im posting cause i have the same issue i run a 1.5x1.5x2.0 with an hps 600 SE filter fan dehumidifiers etc. But the electric bill is killing me as its for personal use. So i decide to replace it with led and trying to figure out which one not want to go high on budget so i was searching for something near 400-800euro. Depending what i would get for that money. So lets start!
Techs available best atm on all levels electric sky 300 v2 optic 4xl Hlg 550 r2 easygrow s800 v2(+controller). So lets start if i was to rate them according to youtube growdiaries ppfd charts Par Far red Uv …! i can tell u alot more if u need or want to know! 
1- Hlg 550 r2 But it draws 480w from the wall its dimmable on the other hand but its not how i like to grow. for me now im drawing 630w from the wall not a huge difference.
2-Electric sky 300 v2 It draws 300w but the price is high and also doesnt ship to eu without additional vat so its rocket high cost! so it will half my electricity bills but its a big initial cost.
3-optic 4 xl First the price is high a bit and for me the main issue is the availability to eu. Also additonal con is the cob is overtaken by the Samsung LM301b - LM301h that is used atm on all top boards like the quantum hlg uses.
4- Easygrow s800 v2 + controler It has the latest samsung diodes high numbers etc. a cool controler that has censors in it for temp and humidity on an app on ur phone via wifi(which seems cool) . But i found the company on sites selling leds on eu and some post on instagram one guy running a test grow on grow diaries with the previous version s600 u can check him out. The price is really good like 490 with the controller for 320 watt and a good coverage.
So i decided to do what it will help me probably most without causing major issues to my wallet. my thinking i will keep the hps i wont sell them or something they will be case of emergency type and supplemental on flowering probably!
Im trying to come in some sort of contact with that easygrow guys first and buy the light with the controller use it on veg for 4 25lit plants and then if i see its not enough i will push the hps 250 inside for the flowering stage and with this i will cut my electric bill in half and if the light is good next run ill get another one and go all led. Hope i helped! I wrote them all straight from my mind so some model leters etc maybe wrong! sorry! keep on growing!
I will tell you that hlg is more efficient. So tho two lights may be of identical wattage the hlg lights could match the yield without being turned up as high. For instance my two 125 watt actuals don’t hold a candle to my hlg 135 which at Max is only 150 watts by itself.
yeah i would love to have the 550 i wont tell otherwise but its not within my budget atm! im still married and its for my personal fun and use ! So if i wanna stay married i have to keep my hobby on a budget! lol! ty for your reply!
Quick question. When you say 1.5x1.5x2 you are referencing meters right?
yeap its meters. 5x5 for us but i grow 4 plants max its for personal use and its more than i actually need ! most of them i make edibles ! u can check my Grow diary account im a begginer to say the least but i love reading alot . and had some good results so far.
Ok now it’s making sense to me lol. I was thinking a 550 in those dimensions as feet is a popcorn machine. Lol. I’m not sure Euros to USD, I think they are equal, but on rightbud dot com you can get a
Horticulture Lighting Group HLG-600H Quantum Board V2 R-Spec DIY Kit - 620 Watt that flowers a 5x5 for $758.99 USD which is 688.40 euro. It also says free shipping. They may ship to you free as well.
my electric runs 260 now with lights and fans and stuff. my gas was 360 so I turned rest of house heat down and will freeze before my plants do. I very stupidly started too many plants expecting to kill most of them. now I have 8 seedlings key word now. all are still under humidity domes and if I dont get this dialed in I am going to have to take a step that will raise my electric another 100 a month and I am tired of the universe kicking my butt. budget? ha what budget? how do you budget when nothing is left? lol
Very interesting. I will call electric company. Thanks
Thanks. Not sure what HVAC means.
@Dealra. Heating Ventilation Air Conditioning.
You’re not comparing lights in the same class or size. Electric sky v300, easy grow s800, and optic 4xl aren’t really big enough lights for a 5x5. Neither is the hlg 550 really, but it’s closer than the others you listed.
I run 3 260’s in a 4x6
Each 260 will cover about 2x4 area
Thanks for answering! You are right i didnt mention footprint for any of those or how many do u actually need to fill a 5x5 but all depends on my budget for me and also i have a 5x5 i dont use it all most of the time i want some space inside so i can work with them with ease so i only grow 4 autoflower a time. P.s anyone have any advice over that easygrow light specs company etc.
Get ahold of diyleduk and build what you can afford. That should get you most for your money.
I just figured out what HVAC meant. I’m in VT and my grow tent is in a basement that is only heated by a woodstove. The temp is regularly in the mid to high 60’s. I only grow indoors in the winters which is Nov-May. My electric bill is still up about $300/month ??? I have one small heater in the tent that keeps the heat up around high 70’s. A small fan and small humidifier along with the 2 -400 lights. I really need to upgrade the lights—they are over 20 years old, given to me.
VIPARSPECTRA UL Certified 1200W LED Grow Light,
This light is only $399 and I get a $100 rebate through VT. Do you think this would be ok for a 5x5 tent, but I don’t need the whole tent for growing. Thank you for your help