We don't sleep with the roof vents open but in summer do sleep with the windows on vent. The main issue for us is condensation so we open the windows in the morning to get rid of any condensation. We've never had a problem with air circulation in either the summer or winter. In winter the caravan is always comfortably warm, we get more condensation on the windows in the winter because we don't leave them open on vent them at night but in the morning after a tea or coffee we open the windows for a little while - it brings fresh air into the van and gets rid of the condensation and the van soon regains its warmth. Some people leave electric oil filled radiators on at night to keep the van warm throughout the night we use a higher tog rated duvet in the winter.
We're lucky and have a fairly new van which is allegedly Category 3 insulated etc. This is supposed to mean it can heat up to 20 deg C in a minus 15 outside within 4 hours.
Have been away ion Feb a few times and were lovely and snug and left all windows and vents closed
It was also nice and cool in summer. We kept the flyscreens on the windows closed and that seems to reflect the heat of the sun.
We use our van all year round. I found that if I keep the heater on all night I get a very sore throat and feel very ‘dry’. It is very uncomfortable. So I got an oil filled radiator and leave it on low all night, this works perfectly. Our van is 2005 so not as well insulated as a newer van and the heating is convection/blown air. We are never cold at night using this method. I also leave at least one window on vent to minimise condensation.
In respect to the "dry air" issue we find that having the Alde heating system is better than it used to be with the air heated systems. Indeed, much better.
Our van has adequate built in ventilation for the winter trips.
In the summer and the shoulder seasons we use varying degrees of cracked open windows, open skylight, or even open the door into the canopy in the heat of June in France etc.
I'm with JTQU. Once you have had Alde heating you will never go back to blown air. Turn it on , set the daytime and night-time temperature and forget about it.
DaveS1
In the winter I never found the blow air to be.very good. Main fault with the full set up is you set the required temperature the van reaches the set temperature and as you would expect the heating cuts out. Problem is the fan keeps running now pumping cols air into the bathroom.
My usual winter set up is put the fire onto low setting turn up the thermostat to highest setting and let it run 24 /7. I have a very smal oil heater for the bathroom that I leave running and everywhere in the van is nice and warm even on the coldest of nights.
I always use my fire on the electric setting only use gas for the initial boost to get the van heated up when arriving on site.
Sometimes leave the kitchen window o the night vent if it’s a still night just for some extra air circulation.
I`m with DaveS1 and JTQU get Alde heating and any thing else is second best, warm and cosy 24/7 with no sore and dry throats as was experienced with my previous van that had blown air. O also much quieter
Unless someone has blocked the air holes a caravans the air circulation should be very good, my blown air is also very good and keeps an even temperature in all parts of the caravan.
However you say you have had a sore throat and blocked nose, that's worrying as flu like symptoms can be a sign of Co poisoning, it could also be a sign of damp in the caravan, it could also be caused by foam mattresses.
As well as smoke detectors CO detectors are very important items in a caravan, plus a Co detector will/should alert you to a failing overcharged battery.
As with above.
I have Alde heating great when in cool or in cold weather, van is also Category 3 insulated.
Cannot beat it, but other good systems are also fitted in vans.
Only thing with Alde heating it cannot cool a van down, so in summer you have to have a fan on, inside the van, windows and vents open to just to stay cool.