HexChat is a cross-platform IRC client based on XChat, but unlike XChat it's completely free. HexChat is very easy to use and has a lot of features, HexChat has lesser bugs than XChat. Here is an easy guide to install HexChat on Debian 7.
Download the Hexchat package from here
Go to the place where you have downloaded the file.
Unpack the Debian package.
sudo dpkg -i hexchat_*
If the install fails run the command below.
sudo apt-get install -f
If you are prefer
sudo gdebi hexchat_*
Now you have HexChat installed on Debian. If you have any problem feel free to leave a comment below.