Dscf0292 DIY AC. …a student, with limited funds and a cheap house without air conditioning. To avoid dying this summer, I’ve built a primitive air conditioner. It’s a basic heat pump, using water as the medium. You’ll probably need to fiddle a bit with the dimensions of the supplies based on your resources and preferences. The system will cool an average room to a comfortable level in approximately 15-20 minutes. Depending on flow rate, a full bucket of water will last approximately 1-3 hours. It doesn’t rip quite as hard as central air, but for less than $30 CAD I’m not complaining. [via] Link.