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View Full Version : Sweaty toilet bowl - how to prevent?



Geoff Ruby
07-15-2006, 04:11 PM
Hi,

My bathroom has a skylight. My current toilet is unlined. Particularly during the hot humid summer months, the light and heat beat down on the tank, which then sweats and drips onto the floor (which is wood).

How can I prevent this?

I am thinking of purchasing a new toilet. (I don't like my current toilet, so if I can solve the sweating problem and get a better toilet, I'm all for that). Possibly one with a lined tank. I am also considering something like the Toto Ultramax, or one of their other one piece models. I'm a bit worried though, that the tank, being unlined, may still sweat.

So, can anybody fill me in on how the one piece Totos are with sweating?

I'm also open to any other ideas you might have to fix my problem.

thanks,
Geoff Ruby

jadnashua
07-15-2006, 04:30 PM
One way to solve this is to put a tempering valve on the supply to the toilet. This is basically a valve that mixes the cold water with some predetermined hot to put the mixed water temperature above the dew point. You need access to hot water to the supply valve, though. If your supply water is cold enough, insulation won't help. Are you on a deep well?

Geoff Ruby
07-15-2006, 04:43 PM
Water supply is municipal water (from Lake Ontario). I don't know how well a tempering valve would work for us - the water heater is a long way from the toilet in question - so the water has to run for a long time before it gets any heat if we haven't used hot water in a while. And, it would involve plumbing, tearing up the floor etc (am I correct there?), and I'd like a better toilet.

We've looked at replacing the skylight and/or getting a custom blind installed, but a new toilet would be considerably less expensive.

In all seriousness, I'm hoping a new toilet is a viable solution, as I think it would be the cheapest, easiest way to go, if it will solve my problem. And, did I mention yet that I'd like to get a new toilet?

Thanks,
Geoff Ruby

jadnashua
07-15-2006, 05:01 PM
This comes up occassionally. INsulation only helps a little bit. If the toilet is flushed several times, the insulation only slows the transfer of heat - it will be overcome and get cold enough to sweat. An air conditioner or dehumidifier helps. Maybe someone else will have some better ideas.

Most of the new low-flow toilets don't dump all of the water out like the old ones did, so that means that the incoming water is mixed with room-temperature water which would help a little bit. They rely on the height of the water in the tank to help provide some of the needed pressure, but stop the flow before the whole thing empties.

plumber1
07-15-2006, 06:53 PM
Take a good look at the toilet again, It may need to be repaired..........

Geoff Ruby
07-15-2006, 10:08 PM
I think the existing toilet is ok, it is not leaking, the problem pretty much goes away in the winter - the problem is it's hot in the summer at least (high 90s tomorrow, well over 100 with the humidity factored in), the water here comes from a very large, deep source, so stays quite cold, the existing tank is 13 L (3? gallons), so there's a fair bit of water and surface area, and this is made worse by the skylight - probably a poor quality one. On a hot summer day it's like an oven in our washroom.

I was also shown a toilet which held the water in a container that did not contact the tank's walls except during the flush. That might be the way to go? Can't remember the brand - I'll try and do a return visit tomorrow and find that out.

Cheers,
Geoff Ruby

Verdeboy
07-15-2006, 11:07 PM
I was also shown a toilet which held the water in a container that did not contact the tank's walls except during the flush. That might be the way to go? Can't remember the brand - I'll try and do a return visit tomorrow and find that out.


I just installed that type of toilet for some friends of mine. Took some getting used to, but I think they like it now. We live in New Mexico, where it's dry, so I can't say if it'll help with the condensation problem. But it seems like it would, since the water only contacts the tank when you flush. Have you tried one of those furry tank covers? They also make a booster fan that fits in your AC vent to help cool down areas that need extra cooling (or heat them up in the winter). You would think that without a liner, the water in the tank would assume room temp. pretty quickly.

I vote for a dehumidifier coupled with a furry tank cover. :cool:

Eric

biffnh
07-16-2006, 01:45 PM
I doubt that the skylight has anything to do with it - other than the sun beating down on it will warm it up and help evaporate the condensation. It is the humidity in the air that is the culpret. I have not found that insulation works. Tempering valves do work and I have had success with them - even thought the water heater is a long distance away the water in the hot water line was warm at one time and is now likely to be as warm or warmer than the air temperature and this will stop condensation. If plumbing one in is difficult consider going to a toilet that uses no water in a tank. I have two compressed air toilets in my house (20 years now) and they are terrific. 0.5 gallons per flush, no sweating and no double flushing!
I highly recommend them.

jimbo
07-16-2006, 05:50 PM
I agree with Biff's post....the skylight has nothing to do with it. Condensation happens when warm moist air hits cold porcelain. If the sun could heat the tank or bowl enough, there would be no condensation. The issue is warm moist air. A ceiling fan or any fan to circulate air would help. An insulated tank would help. A dehumidifier would help.

Geoff Ruby
07-16-2006, 07:14 PM
It was indeed the Niagara flapperless that I was looking at.

I pretty much agree that it is the humidity in the air that is causing the problem. I think the skylight does make this worse, due to the fact that it heats up the room, and the warmer air is, the more moisture it holds. It's also probably true that when the sun does directly beat down on the toilet bowl, some of the condensation is burned off.

Given the comments to my question, I'm now leaning to the Niagara toilet to see if it eliminates the problem or limits it enough that I don't have puddles on my floor.

Any other toilets (ie the compressed air ones, for example) that you'd recommend I have a look at?

Thanks again,
Geoff Ruby

jadnashua
07-16-2006, 07:20 PM
Hotter air is capable of holding more moisture, but unless some is added, the relative humidity actually goes down as the temperature goes up.

Pewterpower
07-16-2006, 07:34 PM
I'm guessing that you don't have AC.
And if the skylight is not well insulated, or not tinted, then I can see how it would get damn hot in there in the summer. You said you don't have the problem in the winter, right?
Try covering the skylight with cardboard (or something that won't permit alot of the heat/light to come in) for a couple days, and see if the tank still sweats.

jadnashua
07-16-2006, 08:10 PM
Watch the relative humidity during the day...as the temp rises, the humidity goes down, as the sun goes down, the temperature often falls to the dew point. The warmer room is less likely to sweat than a cooler room unless there is standing water in the room that is evaporating to raise the absolute humidity level.

If you use a tempering valve, even though the hot water may not actually make it to the valve, it will be at least at room temperature rather than much below as the cold water could be since it came out of the hot water tank. That is the best solution as if the toilet gets flushed several times in sucession, the insulation only slows the heat flow, not stops it...it will still sweat.

plumber1
07-17-2006, 08:10 AM
Tank cover is not a good way to go.

If it was my problem I would try putting a small $10.00 fan on a shelf in the bath room and move the air.

How many flushes does that toilet get? Seems to me if it's not flushed more than once every 2 or 3 hrs that there wouldn't be excessive condensation. If there is do you know how to prove that the toilet isn't leaking through?

Verdeboy
07-17-2006, 10:46 PM
A tank cover on a sweaty toilet tank absorbs the moisture and then mildews and stinks because it never dries. No offense, but not a great idea.

My thinking was to put it over the tank when it's dry (or dry the tank yourself and then put it on.) The cover would then act as an insulator between the cold porcelain and the moist air.

But if your experience shows that this doesn't work, I won't disagree.

Eric

Mikey
07-18-2006, 06:13 AM
Buy a submersible aquarium heater (under $25):

http://saltaquarium.about.com/cs/setupequipment/tp/TPheaters.htm

Maybe you could combine an aquarium and the tank somehow, but the fish wouldn't enjoy the flushing experience...

plumber1
07-18-2006, 07:28 AM
A furry cover is just a place where grime and mold grows.

geniescience
07-18-2006, 08:56 AM
i have enjoyed this thread so far. Every post has had good info.

i'll add more information:

a.) It's the DEWpoint that is the essential thing to know, and you can see it on the Weather Channel or on http://www.weatheroffice.ec.gc.ca/
b.) Lake Ontario water is VERY cold.
c.) This cold water making its way up into your tank after two consecutive flushes brings the tank's surface temperature below the dew point.
d.) whenever warmer air comes in contact with an object that is colder than the air's dew point, condensation results, and occurs on that colder surface (and then driops off).
e.) this explains why your tank has condensation on it dripping onto the floor.
f. ) try leaving the tank unflushed for a day and tell us if condensation is lessened or disappears.
g.) you may as well put a cheap thermometer in there too. And compare the water temperature to the dew point you can see every day on the Weather Channel, or on http://www.weatheroffice.ec.gc.ca/
h.) if leaving the tank unflushed for a day doesn't eliminate the condensation during your test period, I'll bet that the tank temperature didn't get up to room temperature yet. Try adding hot water to raise the temperature a bit more. This is just a test, to confirm that you have no OTHER problem, and to convince you too that the culprits are the humidity and the tank temperature and only those two things.
i.) the skylight is helping, not hurting. Unless something is constantly evaporating in your bathroom or you have some other problem that no-one has "seen" yet based on your description so far.
j.) the open-cell foam used to insulate inside tanks is not the best insulator, since it is very loosely applied and the substance itself is not waterproof. There is not likely to be any reward to you for insulating your tank with higher-quality materials such as closed cell foam (the great stuff that sprays and fills up space) since you do not appear to me to be the kind of person who will love trying out fidgety little ways to improve things. Note that it could improve the heat-transfer slowdown by just enough to be worthwhile, in my opinion.
k.) Air conditioning that is always ON (even on "low") will act as a dehumidifier, and this is a large part of the comfort it adds.
l.) you still have a few more ways to get room-temperature water to flow into your tank after a flush, without using the hot water line. This will depend on what you do with the cold water line before it flows into the tank.

Let us know if this helps.:)

David

Mikey
07-18-2006, 09:11 AM
Re:

a) How does TWC know what the dewpoint is in Geoff's bathroom?

b) You bet it is. The last time I went swimming in Lake Ontario was Feb 20, 1962, having just capsized a Tech Dinghy off the Rochester inlet.

brrr.

geniescience
07-18-2006, 09:18 AM
mikey

b.) And municipal water comes from down deep where it is always cold.

a.) assume that weather outdoors is an accurate indicator of temperature and humidity indoors too, especially if prevailing conditions outdoors last for a couple days or more. Heat and humidity just somehow manage to get inside too.

but i do believe you knew that.

GR's bathroom may be humider even than that. Is that what you might have meant?

davdid

jadnashua
07-18-2006, 09:36 AM
If the skylight results in the room getting hotter, and no moisture is added, the relative humidity decreases. But, it still doesn't change the dew point.

If the toilet is ont a low-flow one, then consider changing it. Most of the low-flow toilets have a fair amount more water in the tank than is flushed down each time. this is especially true if you go with something like the new Toto Aquia and you don't need the full flush. This means that the incoming water will be mixed with some that is already been warmed some by the room.

Another thing you could try is to open the wall where the pipe runs and make a big loop after expanding the pipe to a large diameter. This would put more volume of water inside of the room that potentially would get warmed some in between flushes when you refill the tank. I'd have to do some calculations to determine if that would be a great idea, but the concept is okay.

Having grown up in Spencerport, I guess it just depends on who supplies your water and where the nearest water tower is...our supply wasn't all that cold in the summer. Given the nature of where the frost line is, it did get cold in the winter. I don't remember this being a big problem growing up, but then again, how often does a kid notice that sort of thing! I run the a/c at home now, and thus, it is a non-factor.

Moving some air across the thing would tend to warm it up so the time it could condense would be limited, and then what was there gets evaporated. But, if this is flushed at short regular intervals, I think you will need to consider a tempering valve, since otherwise, you will just keep chilling the tank and condensing.

Verdeboy
07-18-2006, 11:14 AM
i have enjoyed this thread so far. Every post has had good info.

i'll add more information:

a.) It's the DEWpoint that is the essential thing to know, and you can see it on the Weather Channel or on http://www.weatheroffice.ec.gc.ca/
b.) Lake Ontario water is VERY cold.
c.) This cold water making its way up into your tank after two consecutive flushes brings the tank's surface temperature below the dew point.
d.) whenever warmer air comes in contact with an object that is colder than the air's dew point, condensation results, and occurs on that colder surface (and then driops off).
e.) this explains why your tank has condensation on it dripping onto the floor.
f. ) try leaving the tank unflushed for a day and tell us if condensation is lessened or disappears.
g.) you may as well put a cheap thermometer in there too. And compare the water temperature to the dew point you can see every day on the Weather Channel, or on http://www.weatheroffice.ec.gc.ca/
h.) if leaving the tank unflushed for a day doesn't eliminate the condensation during your test period, I'll bet that the tank temperature didn't get up to room temperature yet. Try adding hot water to raise the temperature a bit more. This is just a test, to confirm that you have no OTHER problem, and to convince you too that the culprits are the humidity and the tank temperature and only those two things.


Isn't science great. It proves, in a long-winded way, what we already knew from the get-go. ;)

geniescience
07-18-2006, 01:05 PM
yes i'll agree.

and i think it is good to take a methodical approach to diagnose problems. Any other route can lead you to spend money on the wrong fix, or to make things worse.

david

geniescience
07-18-2006, 02:37 PM
Thank you, Jim, that is correct, the skylight is NOT helping either, and also not making things worse.

Jim's paragraphs 1, 2 and 3 all make sense to me.

About summer water temperature from Lake Ontario: For some reason it doesn't seem to warm up as much as I would have thought either.

Jim's paragraph 5 says to me that a $10 fan facing the tank would evaporate a lot of the condensation. Perhaps enough to prevent drips. Also worth trying.

David

Pewterpower
07-18-2006, 03:43 PM
Are there any other toilets in the house that have this problem? First floor, second floor, basement, skylight, no skylight?
Is this the only toilet you have trouble with?

Geoff Ruby
07-19-2006, 10:21 AM
Only other toilet in the house is in the basement. (the one that sweats is on the second floor). the one in the basement does not have this problem. It is a completely different climatic zone down there - much cooler.

Also, the only bath/shower in the house is in the bathroom on the second floor - so in addition to being in the upper (and therefore hotter) part of the house, it also sees a fair bit of moisture put into the air. there is a fan that is supposedly venting outside, but it doesn't seem to be as effective as it should be. the toilet still sweats though on days when the bath/ shower isn't used.

Will try to cover the skylight and see if it makes much of a difference.

We do have a/c - but we rarely use it, and even then it's never cranked. I may try it one day and see if it lowers the humidity enough to stop the sweating.

thanks for the info so far.

Geoff Ruby

jadnashua
07-19-2006, 02:28 PM
get a better fan and put it on a timer. Ensure people use it. From what you've said, you are adding significant moisture into the house, at least in that room. Leave the door open when someone is not in there. Check the gap under the door - if there isn't enough room, the fan can't do much when it is closed. Even if you aren't running the a/c, leave the fan running to circulate the air if your system allows that.

geniescience
07-19-2006, 10:13 PM
Geoff,


Only other toilet in the house is in the basement.... much cooler.... Will try to cover the skylight .... We do have a/c.. may try it one day

Whatever happened to the idea of adding HOT water to the tank just to bring the tank water temperature up enough to prevent condensation? This takes very little effort to do.

Do you ever go away for a weekend? Can you check to see if the tank water temperature has gone up enough to prevent condensation when you come home?

Does the condensation happen in all seasons?

Whatever happened to the idea that you tell everyone to use the basement toilet for the next two days?

Please note that a one-day A/C will not do much. If it is a single room window box it may never do enough dehumidifying of the bathroom...

Also please note that A/C is designed to work best as a dehumidifier when it is NOT cranked up all the way, but instead just left on all the time, on "low".

If blocking the skylight is what you want to do, well you know i can't stop you... but you did have more than one person say that it has no effect on the dew point. Think of the condensation on an ice-cold drink. Think about it. Then, add hot water to the ice cold drink and see the condensation stop happening on the glass or tin can as the case may be.

David

Pewterpower
07-30-2006, 07:44 AM
Still sweatin' to the oldies? :p