Is it worth to install Firewall in home pc (only 1 pc)? Since we know that intruders mostly like to attack companies network rather than home pc. Because from my point of view, AV is already enough to protect from viruses, worms or trojan horses, if there is firewall installed, it will consume some amount of memory and proccesor, then the system will become slower as the resource taken by firewall software.

And I noticed that, Firewall doesnt effective if we just a normal surfer (pc not 24hrs online).