I run chillers in addition to fans. I wish the fans were enough at all times, but there is a period of some days that the room temperature in summer is just to much. I only have about 6 degrees. The fact that the sun can shine almost 24 hours a day during the middle of summer does not help. A chiller works best if, of course it is outside the room the tank is in. Does not much good to remove heat from water and dump it in room. They are half the price they were 6 years ago, but are still expensive. The newer models are very efficient though. I use a chiller based on the btu's I need to remove and not the generic requirements in a catalog. Most manufacturers wish for you to buy unit at least twice as large as you need. Unless you have run your tank through a summer season though it is difficult to calculate what your tank temperatures will become so deciding on a chiller size is not easy. Mostly it is dependent on the amount of evaporation the average room temperatures the type and wattage of lighting. Typically most people calculate based on the temperature of their tank becoming 3 to 5 degrees warmer than their room temperature. A simple formula is used to calculate the number of Btu's of heat you need to remove based on initial tank temperature (high point) minus the tanks final temperature times the waters specific capacity to hold heat times the number of gallons in your system. If you know the average high temperatures of the inside of your house during the winter and your desired tanks temperature I can give you the required Btus of cooling needed, as could Yote as he does HiVac work so should be familiar with sizing systems, except he works on HUGE systems. Biffer lives in an arid climate, so do not expect near as much evaporative cooling in a more humid climate. I get only 3 to 4 maximum degrees of cooling with fans. I run one fifth horse power chillers on 120 gallon tanks with 40 gallon sumps, with Halide lighting. I recommend inline chillers with the chiller preferably outside. Most of mine sit in front of exhaust vents that run all year round. In my apartment the chiller sit on a shelf attached to a window sill. After all that I will say it is doubtful in New England taht you will need a chiller unless using very heavy lighting , and experience liitleevaporation. Evaporation eremoves huge amount of thermal energy (heat), so like Biffer says, fans work, and cheaply, but unlees it is hot all the time like in Arizona you should only run the fans when you need cooling or you will have your heaters and fans battling each other.