I'm not too sure either. But I know my bro in law has a SIM and he never gets wet bedding when I come to think of it, whereas I do on my normal airbed.
I think that the bedding gets wet as the moisture from your body, (sweat, everybody does it) condenses in the bebbing where it cools below the 'dew point'. This happens because air in the air-bed is a poor insulator of heat, the closed cell structure of a SIM is a much better insulator and therefore the better option in my opinion, I've used both.
Dave.
------------- Give a man a fish and he will eat for a day,
Teach a man to fish and you can get rid of him for a whole weekend.
An adult can expel 2lt of moisture when breathing overnight. Prime source of condensation. We didn’t solve it as such with early spring camping but putting a thin fleece blanket over our bedding kept the duvet dry and blanket dried very quickly, much quicker than the duvet.
Also, insulating under the bed is very important as it stops the air in it getting as cold as it would just on top of the cold ground. Cardboard works extremely well and can be put in recycling when leaving camp.
I swear by polycotton tents. In the last 30 years, I have spent just two nights in a polyester tent and we got soaked with condensation on both nights. Sold that tent immediately. We use an airbed, insulated on top only and have never had a single issue other than very (and I mean very) slightly damp bedding on a few occasions in the polycotton tents. Easily dried out during the day. We never had elec hook up or any form of heating in our tents.
In my experience a well vented polycotton is the way to go.
Quote: Originally posted by Andy Higham on 21/1/2018
Tell me how can an airbed cause condensation and a SIM not? They are both full of air, the only difference is the SIM has a coarse open cell foam in it.
The condensation originates from the occupants warm damp breath and will condense on any cold surface
The same reason why condensation develops inside a tent: heat meets cold. Remember an airbed us full of cold air, body heat produces moisture with the combination of cold air, thus why a irbeds become damp. Reason why have loads of insulation between bed and body.
------------- New Year: Hesketh Bank
Feb/March: Red Squirrel
March: lakes
June: Morecambe
Aug: Lake District(not camping camping)
October: Red Squirrel
We used to use closed cell camping mats for insulating under our air beds, fairly cheap and work well. when our air beds required regular pumping up each night because of micro cracks in the rubber we opted for sims.
Dave.
------------- Give a man a fish and he will eat for a day,
Teach a man to fish and you can get rid of him for a whole weekend.