Why do walls and windows sweat in my mobile home?

[scooter]

I have a rental trailer that is driving us crazy!! I know mobile homes can sweat but this is extreme. The moisture has ruined furniture. It is causing mold and mildew to grow on the walls. The couple living in the trailer are very upset with us. I told them short of putting in a whole heating system, there was nothing we could do.
When we bought the trailer the central heating unit had been taken out and a 'open flame' natural gas heater had been put in. We suspect this is the problem. We got the renters a de-humidifer, but they say it is not helping. So please if anyone can help.

[NMBowtie]

The direct vent natural gas heaters emit a lot of moisture as a by product of combustion. As a matter of fact, most of them recommend leaving a window or door open slightly to "vent" which kind of defeats the purpose of running the heater to start with. About all you can do is replace the heater with an outside vented unit that will vent through the wall or ceiling or go back to a standard gas forced air furnace.

[flcruising]

When you say, 'open flame' heater, are you referring to a natural gas space heater that is unvented? If so, therein would lie your problem.

Like NMBowtie said, gas appliances emit water vapor as a byproduct of combustion (although he said direct-vent, vent-free is the unvented ones that release into the home). Unless you have a way to remove (dehumidify) or release that water vapor from inside the home (opening windows, which kinda defeat the purpose), it will condense on the cool surfaces. And since you said you bought a dehimidifier, and it hasn't helped, then it is probably undersized for the job.

I think you should buy a cheap hygrometer and see what the humidity level is inside the home with the gas heater. Then shut off the gas and buy them some electric space heaters and see if the humidity drops and the problem goes away. Then you would know for sure if the culprit is the gas heater (I suspect it is).

[Yanita]

Hi,

I agree with the info provided, but also ask your tenants if they are running the exhaust fans when cooking and bathing also. This is also very important.

there are many daily events that also add humidity to our homes...plants, breathing, cooking, bathing, dishes, laundry etc...

As mentioned you really should get a proper heating system installed. Although these vent less heaters are great for emergencies I don't think they were intended as a complete heat source. Make sure your tenants have working carbon monoxide detectors in the home.

Yanita

[Greg]

To be totally honest I would not even consider renting out a home without a furnace, one problem related to it and you will be hanging in court. Greg