I am well aware of that and am looking to upgrade once I get all the logistics worked out such as where to store the water needed for water changes with the larger tank. I have very limited storage space right now and I like to store the water near his tank so it stays at the same temperature as the water he's in. Plus we recently had our first Petsmart open so I now have more options than our tiny local fish store's stock of tanks.
I do keep his tank near the heater and keep it turned up to make sure the temperature is at least consistent even if it is a little low. He gets daily 100% water changes and I shift the gravel around as well to make sure all the gunk comes out each day.