less heat or more lumens

First thread on this site (not new to growing but just to this site) Im growing one plant scrog style in a cab that is 26''x20''x5 feet tall witch is in a closet ventilation is a 6 inch sucourt duct fan atached to a diy cooltube with passive intake coming through the botom via a false bottom hideing five 2 inch 90 degree pvc I've recently upgraded my light to a 400w hps with digital dimmable ballest witch I curently run on 75% and keeps my temps at 88 sometimes 89 or 90 when the girlfriend turns the heat to high in the house if I dimm to 50 I can keep temps around 80-82 my question is would it be more beneficial to the plant to have a lower temp and less lumens or the higher temp with more lumens as I said I am not a noob but also not a pro and I am open to any advice people may have

thanks in advanced

i find little to no benefit going over 60-70w psft
and your on 100w psft at 100% so 75 at 75% there is scope to turn it down a little bit if it brings your temps into touch it may yield more at a lower wattage

200w is fine 50psft is still a sweet spot but turning your thermostat down a touch would be better
i would rather run this than silly temps

you could try venting into the living area and intake cool air in may help

more lumens everyday, cannabis is a hearty plant and can take temp variations very easily.

Thank you both for the input I have thought about venting into my main room but am trying to keep things as stelth as possible. Last night before I went to bed I pointed a small desk fan at my intake holes and just came home for my lunch break and temps were 86 lights have only been on for about 2 and half hours so they may go up

Unfortunately I was right temps rose back to 88 any other opinions or cheap ways to drop a few degrees?

try to exhaust more air or bring in colder air. maybe air from your basement or air closer to your window were the airs a bit colder, can you close the heating vent to the room your tent is in that way that room gets alot less heat? i have no idea heats a hard thing to manage.