It is called a European bungalow, and it is heated electrically with wall units. It is about 750 feet, and a partly-below the ground lower level of almost the same size. This lower level has had a sub-floor laid on which there is a carpet and under pad but there is cushion floor in bathroom and laundry on top of cement. I put saran wrap on the sub-floor for 72 hours and I did not get any visible moisture build-up at any of the "check" times. But on my humidity indicators the humidity reading is always very high (75 to 85) - never under 50 on the best of days regardless of time of year. The de-humidifier goes continually if I set it at the half-way mark on the indicator, which I usually do. Downstairs shows a higher reading of course but on damp days outside it is really high both on this level and down there. Over the last 15 months I have replaced the carpet on the main level with hardwood and installed a HRV system.
Answer:
Your whole problem is ventilation. Your high ranch bungalow needs windows open and fans in the basement so cool air from the floor is exhausted along with the moisture it contains. Your dehumidifier will not do that past the 60% level and that leaves you in considerable discomfort. The system you talk about is good but before you buy, check out how many square feet of floor space its meant to accommodate. A good one will look after 2600 square feet of basement floor and the house above it.
