From the beginning of our habitat design, we put a lot of thought into ventilation and air circulation topics. We generally like air that is moving and dislike stuffy environments. We also were concerned with carbon dioxide buildup from such a tightly sealed habitat. As we live in the dry Mojave desert, we had been warned by many of humidity buildup issues that we might have when visiting humid areas.
Now that we have been on the road for a few weeks, we have been able to evaluate our build and ventilation strategies. We have been in some dry and extremely humid environments. In fact, as we are writing this, we are in a temperate rain forest listening to rain on the habitat.
One of the first things that we have noticed is that for some reason, we are comfortable in a much wider temperature range in the habitat than we are typically comfortable with at home. We have an indoor/outdoor digital thermometer on a cabinet in the habitat, and we find it really convenient for paying attention to the thermal environment.
We have also found that we have our small Sirocco II circulation overbed fan running basically all the time. It is quiet, hardly uses any power, and really keep the air moving. The fan helps evenly warm up the habitat when running our Planar 2D diesel heater, it promotes good air transfer when sleeping with the overbed windows slightly open at night (we always have at least 2 windows slightly open while sleeping), and it helps cool down and ventilate the habitat while cooking with the windows open.
On the topic of cooking with the windows open, we have found that it is nice having the large window directly behind the stove and counter open while using the alcohol stove. We have been really pleased with how the stove works, but it is nice (and important) to have good ventilation while running it.
We have been surprised at how little we have had to use our heater. Even with the windows cracked at night (by the way, the fine screens on our EuroVision windows have been doing an excelling job at keeping even small insects out), just our body heat and the small amount of waste heat from the refrigerator is enough to keep the habitat 25-30 degrees F above outside air temperature. If it is a little chilly in the morning, we just run the heater for a few minutes to encourage us to get out of bed.
We have also been using the heater to help with humidity. After showers or coming in with wet clothes after a hike, we have found that it is nice to heat the habitat up pretty well with the heater to help evaporate all of the water and then we run our Fantastic vent fan to blow all the hot, humid air out. So far everything has been quite dry. To date, the only humidity issue we have had was related to the insulating plug that we made for the Fantastic Vent. The top surface of the plug seems to get damp if we leave it installed for a few days, so we have stopped storing it in the fan opening and we only put it in place when we want to block out light.