Finally getting rid of our old inefficient boiler. I want the new one to be powerful and be able to cope with DH, myself and 2 teenage boys showering in the morning, often 2 or 3 of us at once. Ds3 and DD have an evening bath and ds2 often another shower at this time after rugby or similar. I don't want the bath to take a half hour to run either.
I gather a combi is out but what do I actually need. And what's a megaflow. TIA