Choosing a central humidifier

[Captpetek]

I'm looking to have a humidifier installed on my gas furnace. The first contractor I contacted was referred by a friend. He asked questions about square footage, type of furnace, location etc. He recommended the Aprilaire 700 but recommended he come to the house for a proper estimate. When he arrived I realized I had underestimated the size of my house (I told him 3000 sq. ft. instead of 3800). He then recommended the AutoFlo s2000 steam humidifier. His reasoning (which made sense to me) was that the Aprilaire only provided moisture when the furnace was running and would most likely be unable to keep the humidity up to the desired level in a house this size. The AutoFlo turns on the system fan when humidity is needed so it provides moisture regardless of whether the temperature of the house calls for more heat. The AutoFlo is $400 more installed so a small part of me wonders if this is an unnecessary upsell.

Then I call another contractor who asks me no questions whatsoever about my home or system. He quotes me a price over the phone for the Aprilaire 700 as well and says that is what he puts in 95% of his installations. His price is comparable to that of the first contractor for the same unit. So now I wonder if he is just trying to make a sale and doesn't really care whether or not that unit will really work for me.

Anybody out there have any advice, info on either unit, or a sense of which of these guys is being the most honest and professional?

Thanks in advance for any feedback!

[AmeriServ]

Actually you can setup both humidifiers to start the system fan to humidify the house.

Any humidifier will only humidify while the fan is operating otherwise the inside of the duct would get very wet. All humidifiers should be installed with a controller to automatically turn on the fan to maintain the home at the set level, BUT they must also have a sail switch or current sensing switch to allow the humidifier to run only when the fan is proved to be running. Again to prevent that very wet duct and subsequently mold and mildew in your ducts and home.

If the cheaper method is used then the sail switch or current switch must still be installed. The cheaper solution is a duct mounted or wall mounted simple humidistat that turns on just the humidifier and not the furnace fan, again the humidifier will run only when the fan is running, in this case the home owner would have to run the fan manually to get the humidity up to the desired level. This is only necessary for some customers as the cost for the automatic control makes the whole job cost more to do it properly.

In my experience the Steam humidifiers are really great, they do a great job as the steam really absorbs into the air well, but they also fail more often due to poor maintenance and complex parts. So if you get one make sure you maintain it real well. The other humidifiers, "bypass, fan powered, drum", are very good also, they do the job and have done so for many homes for many many years.

As for sizing, usually if you have one furnace for your home then the largest humidifier made by Aprilair or Generalair or whoever will work just fine for your home as they are sized for the largest residential units at 5 tons of air. Personally I like the fan powered humidifiers as they are easy to install just about anywhere on anything and they do not require a six or seven inch bypass duct connected back to the supply. I do not think either guy was trying to pull anything.

[mike n]

Humidity Control

You need to ask yourself if you want real humidity control or if you just want to spend money, steam generation is the only way to go because it is the only way to adjust the environment inside your home regardless of outdoor conditions