My grow room is 4' x 2' x 5' and I can't imagine the heat issues I would be having with HPS or MH lights. I was topping out at 85+ degrees, regardless of whether the door was open or closed, during our last heat wave. My only experience is with CFLs but so far I am very pleased with their cost/performance/versatility. From one fixture I can use vegetative, flowering, or even UVB CFLs to fit the particular needs of my grow.
Welcome to the 420 Magazine site and the community of members that gathers here.
There are a few variables to consider when attempting to provide a credible answer to your question. How much ventilation do you have, or are planning to have in that space? How tall are you planning on letting your plants get? Are you considering using a HID with a cool tube type reflector or open air? Are you running or do you want to run CO2?
The short, gut reaction answer to your question is I believe a 250 will make it much warmer than you really want. However, depending on the answer to some of those questions, that may not be entirely accurate.
hi TanR i will be putting in a 4" intake fan and was thinking of a 6" out take fan and im not guna be using co2 and will be hopeing to let my ladies get to about 1ft thn switch to 12/12. I curently use a t5 and 2 extra 125w 6500k cfls but was thinking of moveing up to hps to get better yield/quality
A dimmable digital 400w would be the wisest purchase. Running it at 75% would be perfect for that size room. Of course you much be able to maintain environment.