Thanks for the replies.
The load can vary, sometimes there will be a couple of minutes between switching the relay and the load consuming anything over a few mA, other times there is a possibility that full load could be consumed as soon as the relay switches.
There are two PCBs stacked, the lower one contains the relays, transformer, fuses and bridge rectifier, all mounted on a 10 x 5cm PCB. The relays can have a board space of just under 4cm x 4cm, which clearly is not much at all.
The board above has all the digital stuff (microcontroller, switches, LCD, LEDs, etc) A ULN2003 for driving the Relays and LEDs, a 7805 and 7812. The two boards are stacked quite close together (25mm), so whatever I use has to be lower than 25mm.
I did look in to Triacs, but thought it was going to be a really messy solution, based on what I read. It seems IGBTs could be equally messy.
You might have more luck looking for 10A or 15A relays with multiple contacts.
Then you can parallel up the contacts to get your 25A current capacity.
They will probably be smaller in size than a 25A relay.
Do you mean using a 15A DPST relay instead of a 20A SPST? That might just work, I´ll look in to that. I was looking at DPDT and DPST relays trying to do the whole thing of 1 relay instead of 2, but I was looking at 20A and above and couldn´t find anything that would fit. However, I never thought of looking at smaller relays and paralleling the contacts. I will definitely check this out. Thanks