Dealing with humidity

Gents and ladies, assistance is needed.
Since winter is coming, from time to time (with temp changing) we notice condensation on the windows and notice some places on the walls a bit of moisture. So far no mildew or mold. So ventilation is OK, I guess (we had humidity issues in the past, though).
I purchased a small dehumidifier - cheapest Pro Breeze - to reduce this inside moisture, but I’m not sure what to set it on. As for now it shows about 45% humidity, and it’s certainly dryer here now, but we still have some spots that are a little damp.

Is this just a product of cold outside + warm inside or should I experiment with my settings?
upd: after Van_Dweller’s comment, decided to replace our electrical heater with a kerosene one which improved situation drastically. So thanks again for such a great response, we still have a nice not too dry and breathable air, but without wet spots. Sometimes it’s better to be a bit paranoid about humidity level… thanks a lot!

Yes, dehumidifier would work but I will also suggest you to clean your AC filters regularly.


There are numerous factors at play here… Outside humidity is one of those factors. Even with adequate ventilation, you can’t get the inside humidity lower than the outside humidity without active heating, cooling, or dehumidification.

If the humidity level outside is lower than inside, then your ventilation and air circulation is inadequate, or you are using a form of wet heating. Unvented propane heat, like the Buddy heaters are notorious for causing moisture problems, and added insulation tends to aggravate those issues, while hiding most of it. Additional ventilation can sometimes help mitigate the problem.

Dry heat is the best choice, combined with adequate ventilation. That means you need a LOT of dry heat to compensate for the ventilation. You can get vented propane or diesel heaters, but they require cutting holes in your van, something I don’t believe in. Wood stoves offer dry heat, but are not really not practical.

My solution for dry heating & cooking is kerosene rather than propane. I have portable kerosene heaters, cookers, and lanterns. You still need adequate ventilation, but they provide nice dry heat to help keep moisture issues away. They’re cheap to purchase, and cheap to use, a win/win in my book. I have enough heat to keep my van comfortably in the 70’s, even when the outside temps have dipped as low as -60°f, and that’s WITH the necessary ventilation. All my kerosene goodies are the wick type, not the pressurized type, and none of them require any additional power source.

To date, I haven’t found any PRACTICAL alternatives that don’t require an additional power source.


"Smiles are contagious, pass it on!" ~ Van_Dweller

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Hello! Please tell me, what power of a kerosene heater did you buy? And for what area of the room it was enough of this heat? I’m afraid that this winter I’ll face a similar problem, as I want to be prepared for and at least find out the possible upcoming costs.


I sometimes spend winters where it get’s down to -60°f, so I have a big heater, 23k BTU. For most people that would be overkill though. I believe the Kerosun Moonlighter is rated at 8600 BTU which should be enough for most people.

While kerosene heaters are adjustable, the real way you regulate your temperature is with your windows. Since you need ventilation anyway, this isn’t really a problem. Even at -60°f outside, it’s Hawaii inside my high top window van with no added insulation, and not covering up the windows.

The idea of lots of added insulation and insulating your windows means that you don’t have enough heating or cooling power. Having enough heating and cooling power is cheaper, easier, and more effective than insulation. Insulation has it’s purposes, like for sound deadening in rattle trap cargo vans, but for temperature control, nothing beats proper equipment.

Many people also just use their wick type kerosene cook stoves for heat. Some people will their dutch oven with sand or dirt, then turn the stove off when they go to bed, and it will continue to radiate heat for many hours. If it’s cold enough, I just run my heat all night. Unlike with pressurized propane, with wick type stuff, the worst that happens if the flame goes out, is you might get cold. No explosive propane problems.

You can get kerosene heaters, cookers, and lanterns in many shapes, sorts, and sizes. I stick to the non pressurized wick type ones, rather than the pressurized types which are also available. I feel like they are safer.

Many people use these Bunsen Sports Heaters, they are heaters, and if you take the top off, it is a one burner stove. Not sure how many BTU’s they are, but they are pretty popular for campers. You have to buy them used though, they have been out of production for years now. Ebay might them.


"Proper Planning is preferable to premature failure" ~ DreamLife

There is a fundamental problem with RVs that is seen in several types. If you notice in home construction there is something called a vapor barrier on the warm side of all the exterior walls. What it does is prevent moisture laden warm air from making contact with cooler surfaces. Thus preventing condensation. Like what your seeing on the inside of your windows.

The solution isn’t easy. What most modern boats do to help resolve this is use a closed cell spray on foam so no air can get to the colder exterior surfaces. IMHO it’s about the only solution but requires it be installed in the build out.

As far as windows your only real solution is insulated glass, which has it’s own set of problems in a van. Like the frames aren’t made for insulated glass. So once again you’d have to solve the problem in the build out.

Condensation is the killer of all RVs as it inevitably leads to mold issues. What I do in my situation is I always run the engine for a while till the heater is blasting, roll the windows down a bit so air can exchange, and dry out the interior every day. Takes about a half hour to an hour but it means my little home doesn’t stink.

Hope that helps :wink:

now to see if this thing lets me post. I’m kinda new here.

PS kerosene stinks and costs a fortune. Use candles in a camp safe holder if you’r going for ambiance :wink:

Hmmm, must not have spell check, not a prayer I spelled ambiance correctly