By router I assume you mean WiFi AP, firewall and router. I run pfSense on an Intel box I got from AliExpress (i5-6200U, 8GB ram) as my firewall and use its 6x

By router I assume you mean WiFi AP, firewall and router. I run pfSense on an Intel box I got from AliExpress (i5-6200U, 8GB ram) as my firewall and use its 6x Ethernet ports for basic routing. Despite having a decently powered spec, in operation it takes 8-9W power. Searching AliExpress for pfSense returns lots of options, many will have lower consumption. For WiFi I have a tp-link AP (EAP-225) that takes about 3W. This is a bit more than an all-in-one consumer unit (the one I replaced was a couple of watts), but I'm very happy with its power consumption.