View Full Version : Insulated tank and a skirted elongated toilet

08-04-2012, 10:48 AM
We are on well water and I believe that requires an insulated tank (to prevent sweating). However I would like a skirted elongated toilet for our ensuite re-model and am getting the run around. We are considering Toto Aquia11, Nexus and AS Cadet 3 with concealed trapway, but apparently none of these come with an insulated tank It has to be a reliable toilet, and dual flush is not my first choice because of the small water spot and streaking. Anyone have a suggestion?

08-04-2012, 11:36 AM
Well water alone isn't going to necessitate an insulated tank. Is your water exceptionally cold? Is it exceptionally moist in the room being remodeled? Those two factors are usually what you look at when being concerned about sweating.

However, unless those two things are true AND the toilet is going to get an exceptional amount of use, flushing over and over and over in an hour, like in a restaurant bathroom, say (more correctly, a POPULAR restaurant bathroom), this isn't a concern in modern low-flow toilets, and here's why:

As you know, sweating is caused by very cold water chilling through the china to make it cold on the outside of the tank, and, in a very moist environment, the water in the air condensing on the cold tank.

In a Toto low-flow, the tank fills to hold several gallons of water, even if it is going to only use a little more or a little less than a gallon in the actual flush (the rest of the 1.6 or 1.28 gals per flush is the water used to refill the bowl). It holds several gallons, but it only dispatches, say, one in the flush. Why? Because the weight of the extra water in the tank causes a higher water pressure going through the flush valve, so you get a pressure boost from that extra water, even though it doesn't exit the tank.

Because the tank doesn't empty on each flush, any new water coming in to refill the tank will necessarily mix with the water already there, thus moderating the effect of new cold water being introduced. If it's a while before the next flush, the water will be at room temp by the time the cycle happens again, and thus no worry about sweating. Also, because the tank is only pulling another 1.28 gallons from the water pipe, rather than 3 or 5 gallons, the water coming into the toilet will likely have been resting in the pipe in the wall for a while, again acclimating to room-ish temperature. Let's say you have 3/4" PEX water lines in your house. 5 gallons/.0184 gals/linear foot = 271. So the water in 271 linear feet of pipe is required to pull that 5 gallons. The water in only 70 linear feet of pipe is required to cycle a 1.28 gpf toilet.

So...the water going in is likely to be warmer, and it's mixing with water already in the tank. Unless you are flushing the toilet a whole heck of a lot (and the toilet is in a moist, un-air-conditioned room), sweating really isn't an issue.

In the Toto line, only the Drake (and lesser Carusoe) are available with insulated tanks. I think that Terry said that he had sold some in like Alaska.

Want a skirted elongated toilet? You have a lot to choose from! Do you like the looks of the Carlyle II (which I have)? I think it's excellent! How about the Soiree, Guinevere, Vespin, Carrolton, Nexus, Vespin, Carolina II, Legato, Lloyd or Ryohan? Look them up online and check out the photos until you find one you like!

08-04-2012, 12:48 PM
That is the best information I have received! Thank-you. However, I did not mention we have a water source heat pump and when it is running the AC, the pressure tank sweats like crazy, but not during the heating season. We have hot humid summers and very cold dry winter air. Still, given the long run of pipes from the pressure tank to the ensuite, I think I will be OK. The ensuite toilet does not get very frequent use. Thanks again - good information! I might have guessed Toto would not sell uninsulated tanks if they had problems

08-04-2012, 12:59 PM
If you find that it does sweat (and odds are that it won't), the other solution to this is to feed it with a tempering valve to mix in a small amount of hot water to bring it above the dew point. If you're doing remodeling and have the walls open, you might consider running a hot supply line over there - you don't have to use it. Put in a tempering valve, but adjust it to all cold and only add heat if required. If you need it at all, you may find you only need it for a couple of months of the year and can adjust it back to all cold for the rest.

08-09-2012, 05:25 AM
From the hot water tank, I have 45 feet of uninsulated copper pipe running in a dry-walled basement ceiling to the ensuite. The cold line was insulated above the finished ceiling to stop it sweating and staining the ceiling. The "hot" and "cold" are about the same temperature for quite a while when a valve first opens in the ensuite. Tapping into the hot may not help. What do you think? I installed an elongated insulated Cadet 3 in the family bathroom 4 years ago, and so far, no problems, but it extends 30.5" into the room - too much for the ensuite. We do not want a round front, so maybe I will take a chance on the Aquia 11. It is a very nice looking toilet.

08-09-2012, 09:35 AM
Just remember that the Aquia, like most dual-flushes, has a washdown flush as opposed to the others which have a double-cyclone flush with siphon jet.

08-09-2012, 03:43 PM
With modern, low-flow toilets, unless flushed frequently, the water in the lines and the mixing in the tank with what's left, keep the tank from sweating. Keep in mind that even if a tank is insulated, if you flush it often, the insulation only slows the transfer and it can still sweat.

08-09-2012, 08:55 PM
I sometimes sell the original TOTO Drake with insulated tanks in Alaska and Washington. Last week it was Wasilla AK.
I wonder if the Drake tank will fit on the Vespin bowl.
The Vespin II uses a Drake II tank.

It would be the ST743SD for an insulated Drake tank.

08-31-2012, 03:51 AM
How does the wash-down flush vs the double cyclone affect the bowl cleaning efficiency and does it impact the tank sweating?

08-31-2012, 02:25 PM
There should be no impact on sweating with the possibility that the double cyclone is a 1.28g flush, and some of the older washdown versions were 1.6g (the tank's size is the same, so the smaller flush has more water left in the tank to temper what's coming in). The double cyclone comes standard with Totos SanaGlos finish (which is smoother, so stuff has trouble sticking to it) and literally swirls around the bowl from the rim from two horizontal holes verses the wash down which uses lots of smaller holes spread around under the rim pointing down. the double cyclone does more with less. The wash down bowls either came with, or often could be ordered with SanaGlos as an option.

08-31-2012, 02:56 PM
I was actually referring to the washdown flush of the Aquia, the Duravit wall-hungs, etc. By that I mean it has no siphon jet; it just dumps a bunch of water into the bowl, just like my 1926 AS toilet does.

As noted, in and of itself, it shouldn't affect sweating. As to cleaning efficiency, I will defer to others. The big water dump into the bowl of a washdown, and the fact that it is all dumped into the bowl instead of partially through a siphon jet, probably stirs things up effectively, but there's the "did it all go down" issue that comes from absence of siphon jet.