Heating and Electrical systems should be installed and maintained by professionals. Don't let unqualified friends try to install these themselves! Even if they get it up and running without suffering any shocks or burns, do-it-yourself electrical work is a common cause of house fires, and a poorly-installed heating unit can leak dangerous gasses. And even if faulty wiring doesn't lead to a house fire, having a professional replace it usually costs more than having it done right in the first place.