Luckily, one of my first acquisitions as a homebrewer was a Counterflow Wort Chiller. In fact I made it by myself, but based on someone else’s design. I’m proud of it, because it looks like a home-made, homebrewer’s chiller.
As quoted from Palmer’s How To Brew:
Counterflow Chillers are a bit more difficult to build but cool the wort a bit better. Counterflow chillers use more water to cool a smaller volume of wort faster than an immersion chiller so you get a better cold break and clearer beer. The drawbacks are keeping the inside of the chiller clean between batches and preventing hops and break material in the kettle from clogging the intake. A copper pot scrubby can be attached to the end of the racking cane to help filter out hop particles.
The increased efficiency of a counterflow chiller lets you use a shorter length of tubing to achieve the same amount of wort cooling. The tube-within-a-tube chiller can be coiled into a convenient roll. The hot side of the chiller, the racking tube intake, needs to be copper or another heat resistant material. Plastic racking canes tend to melt from the heat of the pot when the hot wort is siphoned into the chiller. Counterflow chillers are best used when there is a spigot mounted on the side of the pot negating the need to siphon the wort.
I sure had my ups and downs on the first attempts to make it work, but it was worth it. Now I let the beer flow freely through the chiller and in no time it is in the fermentation bucket at the right temperature.