Jadnashua
Retired Defense Industry Engineer xxx
Keep in mind that insulation may not stop the tank sweating...insulation only slows down heat transfer, and with a deep well and cold incoming water, if it is flushed several times, it could still get cold enough to condense on the outside.
It would really help if the tank wasn't against the wall! That can occur when the toilet flange rough-in isn't set properly (nominally, 12" from the wall). The only thing you can do then is to select a toilet that either has a smaller RI (say a 10" one on a 12" nominal flange) or pick one that is known to be shallower. I'd also leave the door open when I wasn't using the room so that the a/c can help keep the air dryer. It can't add a huge amount to the electricity bill, and certainly far less than mold remediation.
The only 100% certain thing you can do to prevent sweating in a toilet is to use a mixing valve to raise the water temperature above the dew point. This doesn't waste much energy since you're not using a lot of hot water in the mix.
It would really help if the tank wasn't against the wall! That can occur when the toilet flange rough-in isn't set properly (nominally, 12" from the wall). The only thing you can do then is to select a toilet that either has a smaller RI (say a 10" one on a 12" nominal flange) or pick one that is known to be shallower. I'd also leave the door open when I wasn't using the room so that the a/c can help keep the air dryer. It can't add a huge amount to the electricity bill, and certainly far less than mold remediation.
The only 100% certain thing you can do to prevent sweating in a toilet is to use a mixing valve to raise the water temperature above the dew point. This doesn't waste much energy since you're not using a lot of hot water in the mix.