Two points to bear in mind with SSRs (at least the ones I have looked at):I would opt for SSRs (solid state relays) rather than electromechanical ones.
a) they drop a minimum voltage across themselves, due to the nature of the control circuitry; typically 3 volts. This is no problem if you a switching a low current load. However if you're switching a high current load such as a 3kW heater, in the UK this results in a current draw of around 12.5 amps - resulting in a dissipation of nearly 40 watts in the SSR. In this situation a relay is much more efficient in terms of energy loss in the switching circuit (but there may of course be other reasons to prefer an SSR).
b) Some SSRs come with a "snubber network" across the "contact" - typically 10-100nF in series with 100 ohms. This passes a small current even when the SSR is turned off, and the current can be sufficient to (at least partially) turn on the load.
Statistics: Posted by stevend — Mon Dec 29, 2025 9:08 am