Choosing the best evaporative cooler pad can be difficult since it's effectiveness tends to change with the weather. Here is a guideline though that can help you find the right pad material, no matter the season.
When the weather is warm, you will want to use an evaporative cooler pad that is made from wood. Because wood absorbs a portion of the water, it cools some of the air that passes through its wood fibers. This causes the air coming out to be cooler in temperature. The aspen pad is one of the most common wood pads and is made from shaved aspen trees.
This type of material is cellulose paper that comes in the form of honeycomb shaped blocks. CELdek media is a little more efficient than wood and provides a greater drop in temperature. This is because the material is thicker than the wood shavings are, so it absorbs and holds more water. This material is also more expensive though than wood is.
Plastic cooler pads tend to be cheap, however not as effective in cooling the temperature as both wood and CELdek media. They tend to be thinner, so less water gets absorbed than the other 2 materials.
If you are looking for the best evaporative cooler pad, these three guidelines can help you to choose one.