So I am running my house fan 24/7 through my grow room to keep it cool. The DIY cool tube I recently built has significantly decreased the heat in the room and has eliminated most of the need for air conditioning. (its been hot as hell outside, around 80, so outside air and my 400w tends to create a need for ac about once a day around 1:30p.m. and then I'm good till night fall)

Ok so here's my question: what will I save on electricity if I run my house fan rather than my ac/house fan.

Would I be better off attaching the growroom intake ducting to a smaller fan? (perhaps from a cooler part of the house)

Depends on how many hours you have it on and how many watts each consume and how much they charge you per kwh.

yes but my question is in regards to how much wattage the ac fan requires (without air conditioning on)vs the energy required for the fan and the air conditioning working simultaneously.

of course it's gonna be less if you only use the small house fan. if you don't need the house ac then why use it? like you said only use it when you need to, and your electricity bill will definitely decrease. running a house fan 24/7 shouldn't add up to the amount of watts the actual house ac uses.

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i dont think he means "house fan" in the sense of a small circulating room fan, he means the fan that is connected to all the vents in his house...the majority of power consumption will come from using the actual AC to cool the house, and it could cost several hundred dollers a month if you use it constantly. the fan shouldnt use too much energy by itself, but if you wanted to save money, just close all the vents except for the one room you have your grow in. alternativly, you could purchase a stand alone AC that uses a fraction of the power of your central AC, and you could just spot cool that one room. i have an SAAC and it works wonders...you can get a small one from compactappliance for i think around 250 shipped...also look around for used ones, you can get good deals on those too...

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