Steam is the only way to go. It will not leave that white residue that non steam units do, and because they actually boil the water, they are much more sanitary inside. I just replaced my EWC 110 volt steam humidifier with a 220 volt skuttle steam humidifiier in my personal house. What part of the country do you live in? I STRONGLY suggest that you make sure you spec and install a 220 volt unit. Even in Southern California, the performance of the 110 volt (12kw) unit was dissapointing. The unit could run for hours and never satisfy the humidistat and shut off. Since changing the unit to the higher steam output 220 volt model, the performance has improved incredibly. Unlike A/C, oversizing the steam humidifier is a good thing (within reason). For what it's worth, both the EWC and the Skuttle both drain off the water to prevent junk from growing inside. The EWC drains completely after use and the water has cooled to below 140 degrees. The Skuttle has a programmable timer that opens the drain valve for 10, 20 or 30 seconds every 30 minutes depending how it is set. Both brands will turn the furnace blower on independantly of the thermostat to humidify the house if needed. You have to remember to shut down the unit for the summer because you dont need it runing during cooling season - it will put extra load on the A/C I had a lot of problems with my EWC steam unit and can not personally reccommend it. The Skuttle that replaced it is a lot simpler of a unit and has given me NO problems. I ended up buying my Skuttle brand new in the box on eBay. Make sure you get a good digital humidiatat with an outdoor temperaure sensor that adjusts the indoor humidity based on the OSA temp. www.ewccontrols.com or www.skuttle.com

1.I would want to see a load calculation in writing for each zone. I question the sizing especially on the furnaces. 2. Keep in mind basements at or even partially below grade have a very low heating and cooling load 3.assuming you have no installation issues with outside venting, I would get a price on Carrier's 58MVC high eff furnace for the main floor/basement zone. 4.as far as heat pumps, you would need an analysis of your electric and at gas rates. 5. If you have humidity issues in the basement, you need to address the issue of why before trying to solve with dehumidifiers. 6. Dealer should address your temperature issue with the master bedroom with insulation check and ductwork size check. I will assume room is the opposite in the winter heating season. Windows are high quality? 7. I always prefer new and correctly sized refrigerant linesets. IMO

david Baldloonie is giving excellent advice. An 80% eff VS furnace with high eff HP is the way to go considering your location/climate and if you are interested in best operating costs. I would not have Trane's XL16i mdl in either AC or HP condensor. It is a problematic unit plus dehumidification is not as good as the XL15i. Why will you not replace your refrigerant lineset? You should unless there are building obstacles. Trane is falling behind on dual fuel eff-I would get a quote on a comparable Carrier or Bryant. You need a load calc for the main floor to verify sizing. apprx 3000 sq ft? five tons? hummm. IMO

Hi folks, can you give me an idea of the cost to install a central steam humidifier such as the Aprilaire 800? We are in the NY/NJ area. We have an existing bypass humidifier and its simply not keeping up with the size of the home, so the HVAC contractor recommended a steam unit. Thanks