Drier air in winter is less comfortable than more humid air. Dry air leads to chapped or cracked skin, nosebleeds, and sinus problems. Moist air is better for plants and people alike. Also furniture. And pets. Lowering the temperature will increase the relative humidity, but it doesn't cause there to be more moisture in the air. Humidity level is defined relative to the maximum amount of water vapor that air can hold (air at 50% humidity contains half as much water vapor as it can; at 100% humidity there's nowhere for additional moisture to go, and you start to get rain or dew). Warmer air has more capacity than cooler air. Increasing humidity levels by lowering the temperature is a little bit like trying to raise a flag by lowering the pole it's attached to. Most indoor plants will do better with a lower night temperature, but most indoor plants are also tropical, so their idea of "low" isn't very cold at all (and in fact, a lot of them can be damaged by temperatures below 60F / 16C). I would not put a tropical plant on a windowsill in cold weather: leaves touching the window can be damaged, and the overall temperature tends to be much colder by a window. If it's not practical / permissible to use an actual humidifier, bringing plants home for the season, grouping several plants together or surrounding plants with damp moss or pebble trays, adding a glass or plastic cover for the plants, or using plants that don't care about humidity levels (and there are more of those than you'd think) are pretty much the only options. To answer the original question: the room I'm typing in right now is about 76F (24C) and 55% humidity. The humidity level is normal; the temperature is a little higher than usual.

There is not enough information in the original post to allow a detailed explanation of the problem, but here are some thoughts: Heat pumps are rarely right sized for both the heating and cooling seasons. They will be oversized or undersized for one season depending on the house and climate. Since your issues are occurring primarily in the winter, I suspect that the ventilation in your house changed when the heat pump was installed. What type of heating/cooling system was in place before the heat pump? Fireplaces? Wood or Coal stoves? An open combustion furnace? All of these devices will exhaust a large amount of indoor air when heating causing outdoor air to enter the house. If you replace these heating devices with a heat pump and do not mechanically ventilate, the amount of moisture in the house during the winter will increase. Did you have any air sealing or insulation done when the heat pump was installed? This can reduce the air changes in your house and cause moisture to accumulate. Often the best solution for high indoor humidity in the winter(outdoor dew point less than 40F)is to increase the ventilation in the house. The lower dew point (outdoor) air being brought in will reduce your indoor humidity. In some cases operating a dehumidifier is best as it reduces the indoor humidity and adds heat to the house. Changing the cycle on your heat pump in heating mode will not reduce the humidity inside your house when the heat pump is heating. Many of the suggestions in prior posts will help reduce your indoor humidity during the cooling season. Reducing the amount of outdoor air that enters your house when the outdoor dew point is above 55F will lower the humidity inside your house. A whole house dehumidifier such as the Ultra Air unit can ventilate and dehumidify your house all year round. Your best solution may be to address any ventilation and insulation issues in your house before replacing the heat pump.

Ugh. If the unit is too big, I really don't understand how so many people could be wrong. I got a prelim estimate from a contractor and he had the 5 ton unit size in there. The unit in my house is too big so I knew the problems of an oversized unit plus I didn't want to pay for more than I needed so I talked to a friend that works at an engineering firm. I gave him all the building info and one of the mechanical engineers run the numbers. They also came up with 5 ton so when the official engineered plans came back from the architect as 5 ton, I questioned it one last time but when they said the system was calculated by the engineers I accepted it. As far as I know it doesn't have a variable fan. Yes, it is a heat pump but I'm in NC where, from what I understand, they use the summer cooling load to determine unit size. I don't know what information is important but here's the HVAC specs from the plans: Inside unit: Mark: AHUH Basis of Design: Carrier FA4CO60 Fan 2000 CFM, .5 S.P, 3/4 HP Supp Heat 13.5 kW Electrical Power 208/3, FLA 37.6, MOCP 60 Outside Unit: Mark: HP-1 Basis of Design: 25HBR360 Total Capacity: 59.5 MBH Sensible Capacity: 45.1 MBH Heating Capacity 58.5 MBH Electrical Power 208/3, FLA 19.9, MOCP 35 Cooling Efficiency 13 SEER Heating Efficiency 3.46 COP

I used Glidden Kitchen and Bath paint decades ago, in a bath that doesn't have ventilation, so it is remarkable that there hasn't been any mildew or mold with the exception of from a leak around a window (on the wall). And the paint looks fresh still. Of course, back then "primer and paint in one" wasn't available. I don't know if a combo product will or will not perform as well over time as separate applications. When I reno'd my kitchen 6 years ago, I made the effort to prime the walls separately - it didn't take that long. Clearly your contractor wants to save time and effort. I hope that you are improving your ventilation (out through the roof, not into the attic!!) so you shouldn't have black marks forming from your showers.