We are sorry to hear this, and we wish you had got in touch with us before returning the unit ! Our units work best in enclosed, well insulated spaces. Room environment conditions such as ceiling height, sunlight, number of windows/ doors and level of insulation can affect cooling efficiency and there are ways to increase the capacity of these units. There could be other reasons for the unit to not cool- temperature setting could be too high, or the exhaust hose may need re-installation to avoid the heat from coming back into the room. Our customer support team will be able to assist you, should you need to purchase another unit in future. Please call us at 1-800-474-2147, Monday - Friday 8:30 AM - 5:30 PM (EST), or send us an email at usinfo@jmatek.com with the reference code number THB0815. We look forward to hearing from you. Thank You !