To start: the not enough heating notification is correct. It shows when the game detects that a building is connected to heating but there is not enought heating so it has to use electricity. I think the developers put it there to warn people before buildings start using a lot of energy for heating. I don't know what the mod should do. I am starting this discussion to see what people think it should do.

1. Should the mod say that a building is connected to the grid only if there is enough heating for it? This way the notification will never appear, even if only some building have heating and others have to use electricity
   
2. Should the mod say that a building is connected to the grid only if there are any buildings that produce heating in the city? If you have any heating plants it probably means you are trying to provide heating to the whole city which means you want those notifications to appear to warn you that you need to build more heating plants. But this has the problem that if for some reason you want to provide heating to only a portion of the city you will still have notifications in the rest of the city. You can of course then set district policies to only use electricity for heating but now we are back to square one, you need to set district policies. Wouldn't it be more intuitive if you just set a city wide policy to use electricity for heating in the whole city?
   
3. Should the mod stay as it is and set all buildings as connected. If you don't want to provide heating you can set the only use electricity for heating city policy and the notifications will disappear.

I think the last option is the best one because it is the one that best integrates with the game because it says the buildings are all connected, which is true. If you don't want to provide heating just set the only use electricity for heating city policy.