How small? Under 900sqft? I've got 70W (20x 3.5W) in ny living room and it is quite bright at 100%, I usually dim to around 20-50%.
I realized I did accidentally almost double my final number, so 500-1000W would be more accurate for the way this condo was built (depending on which extra lamps we are including—does every understair closet light count or just the main rooms, at the low end estimate)