We’ve been in the discussion of home heating and cooling so we figured we post this guide. Sure this might be off-season for most of the readers in the northern hemisphere but will surely work for those down under where Christmas is in the summer and for those stuck in tropical climates. Keeping an air conditioning system has costs both in operation and maintenance. But how can you cool your home without an air conditioner? Simple answer: fans. Fans can cool your home through the science of convection currents (you know, that warm air rises and cool air sinks). And we’re talking here not just of oscillating fans but a combination of well-placed ventilating exhaust fans. Oscillating fans simply move the air around and doesn’t really help in getting hot air out and bringing in cool air in. Ventilating fans do. And the good news is, fans can use only 10% of energy needed for air conditioners to work. However, doing this might also entail a bit of window manipulation to aid the cooling process. Direct sunlight is one heat source that can be blocked off. You can freely open windows in areas under direct shade and close the others in direct sunlight with blinds and shades to prevent heat from warming the inside air. If you have lower floor windows, you may want to open them to let cool air in. At night, you may close them and open the top floor windows to let air in. For the fans, there are several ventilating fan types that you can choose from. Attic fans are permanently mounted to the top floors can even cool the whole house. It works by improving convection inside the house, getting the hot air inside the attic out. However, it would require an opening at the bottom floor like a door or a large window to be open to optimize the “pull” of cold air in. Window fans are less powerful than attic fans but would work in smaller homes. They’re mounted high up on walls where they can pull warm air out. If you want a more portable solution, box fans are your best bet since they can be moved from room to room. Ventilating fans usually are rated according to cubic feet per minute (CFM). The ideal air-change rate is about 20 per hour or that the area is cooled 20 times every hour. You can calculate this by first getting the the room’s volume in cubic feet then multiplying it by 20/60 (1/3). A 10×10x12 room would have 1,200 cubic feet of air inside. Multiplied by 1/3 gives you 400. You need to get a 400 CFM fan for such a room.