Ethereum would be profitable if you have free electricity.

I find the main issue of hosting rigs is supplying them with power and heat.

You have to make sure that there is enough power coming from the breaker box etc. and need to know detailed information about your electrical layout. Many people move into an apartment with electricity included in the rent and want to mine, mine, mine, but don't factor in having to mess with the electrics, insurances problems, and the heat!

The heat for me is why I stopped mining at home. Granted I have rigs full of older, less efficient cards, but the I wasn't able to expel the heat effectively enough and it was quite miserable living with the rigs in the summer.

Just some things to think about.