I like the stand alone dehumidifers better than ones incorprated in to hvac system. When you place the dehumidiferes in the conditioned space they sense the RH in that space, many central dehumidifiers sense the RH in the area they are located in and do not dehumidify the conditioned space as well. Where are you located? Where are central units located? Have you talked to hvac company about adjusting dip switch settings? Many times they are installed with factory settings and need to be adjusted for your climate. ERV's are usually not for cold climates..that would be an HRV, so I wonder about your location. Also ERV's are for 'tight' houses..with less than .25 air changes per hour. If your house is not at this level of air tightness the ERV can bring in moisture adding to the dehumidification load of hvac. Was the house tested for air tightness with a blower door? To 'see' what is happening behind the walls and between floors of your home would require a thermal scan of your home. This will show you moisture intrustion sites and moisture in walls, ceilings and floors. IMO this will be the way to go to actually KNOW what is happening. Then whatever the IR scan shows will be on you to address. Around here (Louisiana) thermal scan (InfraRed) scans are used often when home owners and builders are seeking solutions. I've even seen them used in court cases. But hopefully...it won't come to that! best of luck.

Not that I mean to insult or upset anyone, but it's clear that the cheapest and easiest solution here is to pull out the wood flooring and go back to carpet. I love wood floors too, especially in century houses, and of course it's your house and your choice. In case some encouragement helps, though, I'm casting a vote for saving your nest egg for bigger battles, and putting down really nice good quality carpet. Also, perhaps this can serve as a warning for others. Usually, houses in or close to original condition are the way they are for a reason. In most cases, the original architect knew what he or she was doing. Trying to make an older home look like what it isn't - a brand-new in a new-home style - can end up being much more complicated and expensive than you'd expected. The home "improvement" television channels and websites will never admit that, however. Whatever you decide to do, best of luck with it.

I don't think it's impossible to waterproof a stone foundation. I haven't researched it, and maybe someone else here has experience. My guess is that you'd probably have to parge the stone from the outside with cement or something similar, then add the usual sealer and membrane over that. I suppose you'd have to excavate inside the crawl space to get to that part of the foundation, which doesn't sound like any fun at all. If you just can't do a proper exterior waterproofing, I'd suggest doing all the other (exterior) steps on the list - gutters, downspouts, grading, swales. That will at least reduce the amount of water entering the cellar. If it's still too damp, then you need to remedy that. To consider crawl spaces, ventilating them used to be the standard practice. Today there is a trend toward sealing and conditioning them. Personally, I raise an eyebrow at the idea of heating and air conditioning a space that nobody but mice is living in, but who am I to say? In your case, that's all moot. If your cellar is going to be damp, you have to get rid of the excess humidity somehow. You can run up a big power bill with multiple dehumidifiers. Others may disagree, but IMO, it's more economical to ventilate the cellar. You can replace your cellar windows with crawl space vents, and make one or two of them exhaust fans. Fans cost around $100-150 each, and use considerably less electricity than dehumidifiers. I'll be interested to see what others suggest.

Does it sit directly on the ground, with no air space around it? Could it be coming from under the floor? Does it have a good roof, and if there is an attic above it, you may want to investigate up there a bit too. Since this was once a patio, it may not have been built to enclose, and that could be the reason for the musty smell. Is there any other location for the washer and dryer? If so, I would consider moving the washer and dryer. Obviously, there is mold or mildew somewhere, so may not be an easy thing to find. Its also not healthy to breathe in.