Aprilaire - 700M

I won't go over all the humidifiers I tried, just the final system that worked. First of all, I assume you have a forced air furnace. You need to use the air plenum. Next, you will need an Ecobee thermostat. Others may work, but Ecobee was flawless. The Aprilair 700m (m for manual, no need for a humidistat) will do the job. You will need to replace the filter yearly, but they are relatively inexpensive. Finding a spot for the Aprilair will require some searching. It has to attach on the furnace air plenum. I put mine on the return. No, mold will not grow in the plenum. Next, you have three connections; 1) Water; get a plumber to route a copper line to the Aprilair. It is not intuitive, but run the water line to the HOT side. This will make the humidifier run more effectively. 2) Electrical; I mounted my Aprilair next to the furnace, so I routed 120VAC power from the furnace controller to an outlet next to the Aprilair, and plugged the Aprilair into the outlet. 3) Aprilair control wires. There will be two yellow wires. One yellow wire goes to the "C" connection on your furnace controller. The other yellow wire goes to the ACC+ connection on your Ecobee. Tell your Ecobee that you have a STEAM humidifier (I know the Aprilair is not steam, but the system needs to think it does for the fan to run properly). Set the humidity level you want on the Ecobee, and enjoy whole house humidification.

The Ecobee thermostat/Aprilair 700M humidifier is a great combination. Pipe it to your hot water line. One yellow wire to the Ecobee ACC+ and one yellow wire to "C" on your furnace controller board. Setup the 700M as a STEAM type so it will run properly.

We have an aprilaire 700m humidifier built into our hvac and the best it has been able to do is hold at 37% RH. It does help though.

Where are you located what’s the relative interior conditioned space of your home and where is your HVAC located in your home. I ask because if your hvac is in a location where it won’t freeze and you have proximity to your hot water heater you should get an Aprilaire 700m and install it to the supply duct and plumb it to hot water. If you have a Nest system it will automatically control it and will condition a large home. I have one and it’s plumbed to the first floor hvac and it conditions both the first and second floors.

I switched from three standalone humidifiers to an AprilAire 700 and it works so well that I haven’t had to run the standalone units anymore. It works really well and way less maintenance once you get it installed.

AprilAire 700 if you’re able to install one in your HVAC. Works way better than the standalone units.

Definitely go with the Aprilaire 700 series for that setup - they're solid and handle that square footage well. Since your heat pump runs most of the time you'll want one that doesn't need crazy high temps to work properly and Aprilaire nails that

Thank you for the advice. Is there a recommended evaporative humidifier? I already have aprilaire 700 in the hvac, but that only gets us to 40-45%. Hoping for 50-60% for the young kiddos. Could I replace the aprilaire with something “bigger”? Or wider to have supplemental humidifiers (like I have…but evaporative so I can use tap water). Trying a Canopy in our primary bedroom now, but it appears to lack the ability to get us to our desired humidity levels. It seems to hold around 45%.

EDIT: I missed it was a variable speed, so a bypass won't work very well. As much as it sucks, cutting into the side of the new coil to install a 700 or 720 is probably the best option other than steam. ~~Sounds like a good plan. Use rigid duct, an elbow, and a take-off for more bypass airflow (don't use flex duct).~~ Pipe to hot water. Get the one with the digital control and wire it for blower activation. I also strongly recommend you install the outdoor temp sensor so it can automatically adjust humidity with outside temp to avoid over humidification.

700 and 720 both pull their air from the plenum and put it back in the duct. The vents on the cover of the 700 are for the motor cooling, and the motor is mostly walled off with a plate from the humidifier airflow. There's a little air leakage through the vents, but most of the airflow is going in and out of the duct only.

That is a good question, the answer is yes. 720 is 1.75 GPH vs. 700 at 3 GPH. So you will get more heat gain from the hot water with a 700. The 720 fan pushes a little more CFM than 700 though, which helps it get a couple more GPD. Another hack you can do with a 700 (but not a 720) is replace the yellow flow orifice with the blue one to double the water flow rate to 6 GPH. That gets you more hot water if the yellow orifice wasn't enough (but that's getting to be a lot of hot water usage if it runs all day). You can also increase the thermostat on your water heater (max of 140ºF) and insulate the water line to the humidifier if it's more than a few feet from the water heater to maximize the heat. FYI the hot water thing doesn't work with tankless heaters because the flow rate is too low. Hopefully you have a standard tank water heater.

That is larger house, so you'll need an AprilAire 600 or 700 series humidifier. The type you get also depends on how much space you have on your furnace supply and return ducts. A fan-powered on the supply duct has a bit more output than a bypass humidifier. I would not get the Model 500, that is too small. The 500 is meant for apartments, condos, and small houses. The 600 is the larger size of basically the same thing. The 700 adds a fan for additional airflow.

Aprilaire 700 in a 3,000 sq ft home, it does ok, but we still need room humidifiers in the bedrooms. Steam humidifiers seem to work better, but sometimes too well, causing moisture issues. They use a lot of power too.

$1000 or so installed. Aprilaire 700 works great. Any HVAC company can install one but you'll need a hot water line nearby for them to tap into (make sure they do a quarter stop valve and NOT a saddle valve.)

April Air. Attached to furnace. Fantastic!