Condensation on upper inside walls ral cold morn

Though the De-Humidifier does kick some heat into the house (Note the watts on the id tag and do the watts-BTU math same as if it was a heater).

It is basically an air-conditioner.
Sucks in warm moist air over evaporator coils.. Same as your A/C does. then passes the same now cool dry air over the condenser coils. (The A/C has the condenser coils outside and uses outdoor air on them. passing the cold air back into the RV.)

Learned a long time ago with our first pop-up to let air flow to avoid the condensation. Even on the coldest night our bedroom roof vent stays open some. Would rather have it a little chilly than let that moisture do its dirty work (mold).

I've got a 25 quart per day by Whirlpool that I picked up at Lowe's about 4 or 5 years ago. It has casters on it and I can roll it around if I need to. I don't have slide outs but it will fit under the table of the dinette and still have plenty of room for air to circulate while running. If I needed to use the Dinette I can roll it over by the jack knife sofa or down the aisle towards the bathroom.

It holds about 2 gallons and has an automatic shut-off when the bucket is full. I usually empty it once a day. That's after a 7 to 8 gallon shower every other day while running the bathroom vent, using only the microwave to cook or heat up food and using a 4-cup Mr. Coffee machine once a day.

Padlin wrote:
We carry and use a 15 pint dehumidifier, works perfectly but our trailer is only 140 sq' so you'd need to size one for your trailer. On the down side, they kick off quite a bit of heat, good when it's cool, not so good when it's warm. At times I run the A/C and the dehumidifier at the same time.

Something about running the vent fan with an open window when it's in the 40's just seems a bit off to me so I go this route.

on the heat, a dehumidifier is basically an unvented self contained AC unit. water condenses on the cooling unit, just like a AC unit, drips into the collection pan. but the high side (heat) of the AC isn't outside, it's in the dehumidifier. So, yes they do put out some heat.

We carry and use a 15 pint dehumidifier, works perfectly but our trailer is only 140 sq' so you'd need to size one for your trailer. On the down side, they kick off quite a bit of heat, good when it's cool, not so good when it's warm. At times I run the A/C and the dehumidifier at the same time.

Something about running the vent fan with an open window when it's in the 40's just seems a bit off to me so I go this route.

2gypsies wrote:


The mfg. probably didn't get the wall insulation butted to the ceiling if this is the only place you notice it.

There is probably an aluminum framing member where the condensation occurs, so there is no place for insulation. Aluminum will conduct heat out rapidly.

luberhill wrote:
I know I’m ocd and the damp I feel is about an inch wide path on the very top of the wall where it meets the ceiling.

The mfg. probably didn't get the wall insulation butted to the ceiling if this is the only place you notice it.

ksg5000 wrote:

ktmrfs wrote:
If you have a humidity problem that is visible, this isn't going to help. As mentioned in a previous post my compressor dehumidifier usually will pull 5 gallons of water out in the first 12 hours of operation when we go to the oregon coast. After that 3-5 gallons/day is typical.

What dehumidifier are your using? When I took a look most seem too large/bulky for my rig (29 ft).

Haier (sp?) makes most of the smaller dehumidifiers sold today. The are marketed under the Heir brand and dozens of other brands. Go to home depot, lowes, Fred Meyer, Wally World, Amazon etc. and look at what they have in smaller sizes. Ours is fine in our 35ft TT, and would work in a much smaller trailer. Look for one in the 35-50 pint capacity range. Interesting how they use pints to give big numbers instead of gallons (4-6 gallons)

I think ours is 32ish pints, haier.

ktmrfs wrote:
If you have a humidity problem that is visible, this isn't going to help. As mentioned in a previous post my compressor dehumidifier usually will pull 5 gallons of water out in the first 12 hours of operation when we go to the oregon coast. After that 3-5 gallons/day is typical.

What dehumidifier are your using? When I took a look most seem too large/bulky for my rig (29 ft).

Here in North Idaho, it's pretty damp for months. We've found some dampness under the mattress while stored in the winter. There are products that lift the mattress off the plywood, but being cheap, I use a couple 2X3s and lift the mattress off the base for the winter. Oh, and Damp Rid!
And a roof vent slightly opened.