We have both refrigerant and desiccant machines available to buy online. Refrigerant dehumidifiers - also known as compressor or condensation dehumidifiers - are the most common and well known type. They use a set of refrigerated coils to extract moisture from the air via condensation. They are cheap to run and suited to drying a wide range of spaces. They work best in temperatures above 15 degrees but some high quality models work effectively as low as 5 degrees. Below that temperature level, a desiccant unit is best. Desiccant models extract moisture from the air using an absorbent material on a rotary wheel, which absorbs moisture from the air. They are very effective in colder conditions - even well below freezing. So they are ideal for more challenging areas and harsher conditions.