Running My Heat Pump at 73℉

You need to put a vapor barrier in crawl space if it does not have one and a dehumidifier and get the crawl space down to 45% to 50% RH. Otherwise lots of bad things can happen starting with mold. For the most part venting the crawl space will not help as the outside air is higher than 50% RH. So seal all vents. Got to have a dehumidifier, with a condensate pump. Some install a small vent fan in addition to the dehumidifier to get rid of soil gases, radon, etc.

That sounds expensive but I may do it anyway. I could get a low interest home equity loan
 
My fiancée, who will be my wife in a few weeks, keeps hers set at 78º most of the time when she's in, with an occasional 76º if she's hot. I'm of course not at her house all the time, but being as warm natured as I am those kind of temperatures kill me now. There again, it's not the heat right now, but it's that her house gets incredibly humid with it running so little(and cycling fairly short). It's okay spring/fall but not in the summer. I get miserable at night, and that's sleeping on the couch sometimes without a blanket and a fan blowing on me.

So, when I'm at her house and she's not in(while I'm here) I usually set it down to 74º or so and let it run for a good hour or better. That tends to dehumidfy it pretty well and make it a lot more comfortable into the afternoon even when the temperature creeps back up some. Her house is frm the early 50s and not overly "tight"(even though the windows are a few years old), which to me does make it feel somewhat cooler than modern houses that are sealed up tight.

Her A/C unit was replaced a little over a year ago(maybe May-it actually went out in September of the previous year, and somehow or another she tolerated it until it until the summer heat the next year started creeping in. Hers is not a heat pump but just a stand-alone A/C with a gas furnace.

At least one thing the A/C does have going for it(or at least the thermostat) is that when it comes on, it seems to intentionally avoid short cycling(and will run at least ~20 minutes or so if not longer) even if that means overshooting the set point by a degree or two. I do feel like that does at least help the humidity. She also dries clothes on a drying rack and mostly avoids the dryer-but lately has been complaining about how slowly things dry. We need to have a talk about the easy way to fix that :) .

BTW, aside from convincing her to at least run the A/C with the thermostat set lower :) , one of the things I hope to do(and hopefully before I move in permanently) is replace the door between the garage and the house with something that hopefully is insulated more and seals tighter. I suspect that's the single biggest "leak" and I also suspect it's original to the house. It's a wood frame with 8 single, individually cut glass panes(plus one cracked one that she managed to do trying to kick stink bugs off before going out to the garage. Her garage is wood frame, has siding on the outside and a shingled roof, but still cooks in the summer(insulating it might actually be another good project) and gets awfully chilly in the winter. Every little bit helps. The crawl space is another one, but I can't even fit through the opening :)
 
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