Think summertime. Sitting outdoors on a hot humid day with a nice cold beverage. The cold beverage within the glass causes condensate to form on the outside of the glass. The condensate runs down the glass and puddles on the table top.

In your bathroom, toilets are typically filled from the cold water supply line. Cold water goes into the tank, chills the porcelain, and if the relative humidity in the house is high enough, condensate can form on the outside of the tank, run down the tank, and pool on the bathroom floor.

If you have air conditioning, running the AC dehumidifies a house, making condensate less likely to form on a toilet tank.

But a nutshell answer as to when an insulated tank would be recommended? If you have condensate forming on the toilet tank, then an insulated tank might be a good idea.

Thank you!
Sally

I was at a plumbing showroom and the salesperson told me the new 1.28 gal toilets no longer have condensation issues because the amount of water entering the tank is so little it equalizes in temperature before condensate can form.

Is this true? I'd especially love to hear from Toto users, as I'm considering the Carlyle or Guinevere.

The toilets at my weekend lake place seem to be plumbed to warm water. Is that an acceptable option or is an insulated tank better? We don't care much for AC so condensation on the toilet can be an issue here in the summer. I've been wondering what is the better solution for this?

Gibby,

I did that at our lake house. We don't use AC there as we have the windows and doors open all the time, so I pulled a "T" off the hot water line and plumbed the toilet off that.

It's not that the toilet is getting "hot" water, it's just tepid. Essentially, it's just warm enough to not cause the tank to condense.

If I were to buy replacement toilets for that place I'd get insulated tanks. As to those tank "insulating kits", heck it was faster, less expensive, and more effective to just swap the plumbing from the cold line to the hot line.