When you are installing a kegerator underneath a countertop make sure to seal the space between the kegerator and the underside of the counter. Most built-in kegerators do not come equipped with any type of solution for insulating the beer line that runs up from the kegerator into the tower mounted on top of the counter. If you leave the beer line exposed you will be allowing all the cold air to escape from the kegerator and your draft beer line and tower will not be chilled. This can cause all types of problems like foaming, excessive ice build up and an overworked compressor.
You will have to go the hardware store and pick up a few items. This is a very easy and inexpensive project, but it will add a lot of years to your kegerator and keep your energy bills a little lower. To seal the gap you will need a small length of PVC pipe (6"-10" depending on how large your gap is) and some pipe insulation. This is the type of pipe insulation used around copper pipes in your home, so you will find it close to the copper pipe in the hardware store. Slide a sized piece of pipe insulation inside the PVC pipe to surround the beer line. It is ok to extend the pipe from the interior of the kegerator cabinet up through the countertop and into the base of the faucet tower. A cold air kegerator tower fan can help push cold air up into the tower to prevent foaming caused by temperature changes in the beer line.
You can also use flanges and PVC pipes to create a more permanent insulated channel for the beer line as seen in our DIY kegerator build project and home bar build seen below.The pipe was sealed to the flange with epoxy.