It is important to think about what rate of extraction you require for your kitchen. You will want to make sure your new hood can easily ventilate your whole kitchen. Measure the height, depth and width of your kitchen in metres. Do a little bit of maths! Multiply all these numbers together to find out the volume of your kitchen (height x width x depth= volume). Once you have your kitchen volume, times this number by 10 to find the rate of extraction (volume x 10 = rate of extraction (m³/h).