Use a solid state relays (SSR) with built-in zero crossing.

http://www.components.omron.com/Prod...nd_Relays.shtm
(Omron)

http://www.celduc-relais.com/uk/okpac.htm

http://www.power-io.com/
(Ultra precise zero crossing for reduced EMI, without the cost of external filters).

http://www.branom.com/literature/scr.html
(SOLID STATE RELAYS AND SCR POWER CONTROLLERS Introduction).


Luciano