I want to install a whole humidifier

[lzicc]

I have limited space in my furnace room to install a whole house humidifier. If you look at the picture, the duct on the left is the cold air return and the supply plenum is on the right. If I install a bypass humidifier, I need to install the unit on the cold air return, but will have trouble installing the 6" duct bypass to the supply plenum of the furnace. Can the bypass duct be installed anywhere on the supply duct? I was going to install a non bypass humidifier so I didn't have to worry about the bypass duct, but I think they have to be installed on the supply side, which there is not enough room.

 

[frugalangler]

I use an AprilAire on my HVAC, looks kinda similar, so I'll go down and shoot a couple shots of it and re-post for you. IIRC, though, mine is ducted from output riser (updraft system) to cold return before the filter which basically forces some warm air back thru the humidifier into the cold air supply, it's a loop but not a lot of volume, and works well.

 

[orezok]

Double post

 

[orezok]

I live in the Mojave, so added humidity is a winter requirement. Ive been using a Skuttle spray humidifier for 13 years without fail. I have to annually remove the spray head and remove the calcium buildup, but that is the only maintenece and NO cost. Takes about 10 minutes.

The unit is very small and only requires one 3/4 hole in the supply duct.

Spray Humidifier | Skuttle

 

[lzicc]

I like that idea. It needs to be installed where there is at least 6' of straight, non obstructive space, so it seems like it could be installed in the main supply duct which would be good for me. It just more or less sprays a mist of water into the duct. It says that it is made for low temperature heating system. Mine is a gas, force air furnace which I would think would be high heat?

I live in the Mojave, so added humidity is a winter requirement. Ive been using a Skuttle spray humidifier for 13 years without fail. I have to annually remove the spray head and remove the calcium buildup, but that is the only maintenece and NO cost. Takes about 10 minutes.

The unit is very small and only requires one 3/4 hole in the supply duct.

Spray Humidifier | Skuttle

 

[coldsteelva]

I have an Aprilaire 400 or 600. The water plate housing (square) mounts in the cold air return and includes a humidistat ahead of the water plate and prior to the filter and the warm air duct (round) (that I think you are calling a bypass) is ducted to the warm air supply. That duct has a butterfly with summer and winter positions.

During the humidifying season, warm air is drawn by the fan across the water plate picking up moisture, then through the filter and into the supply ducts. During the summer, I pull the water plate, turn off the water, and close the butterfly essentially closing that air loop.

 

[lzicc]

coldsteelva, you are correct, that is a bypass one. I'm wondering if the bypass duct can be ducted into the main supply line instead of the plenum.

 

[coldsteelva]

I'm sure it probably CAN, so long as the distance in ducting is less than some pre-determined 'draw' distance. Without enough airflow across the water plate, the water won't evaporate. I'm sure that info is in the manual; I'll try to find mine.

 

[Cord]

A bypass might be your best option. The supply connection can go anywhere on the supply side, but try to install it well before trunk T. If you get it too close to the T or after the T, you could run into moisture distribution issues where a portion of the house isn't seeing the moisture. Make sure you tap into soft water and I'd suggest using hot water. There are direct injection systems (steam or spray), but they seem to demand a higher level of maintenance.

 

[orezok]

I like that idea. It needs to be installed where there is at least 6' of straight, non obstructive space, so it seems like it could be installed in the main supply duct which would be good for me. It just more or less sprays a mist of water into the duct. It says that it is made for low temperature heating system. Mine is a gas, force air furnace which I would think would be high heat?

My system is propane forced air so I would say that it probably meets their low temp heating system requirement. Mine is installed in the A/C plenum just downstream of the evaporator coils.

 

[s219]

Have you looked at the Aprilaire 800 steam humidifier? Different install arrangement which may work better for you -- just put a steam nozzle into the supply duct downstream of the furnace and the humidifier unit can mount off to the side on a wall in the room.

 

[lzicc]

I did, but they are around $700.

 

[Wilco]

How many sqft is the house? The 600 is a good unit for <2000 sqft. More than that I'd look at the 800 steam.

 

[RalphVa]

We didn't have one for the upstairs of our house. The circulator is in the attic where water for a humidifier would freeze. So, we put a Honeywell Truesteam unit in a closet in our master bath room. It's just on about the 3rd shelf in there. The wife has sheets stacked on the rest of the shelf. We had a few problems with it until one of the technicians found the steam line wasn't completely straight, e.g. had some very slight sags in it. After the sags were removed, it has been troublefree. Just needs cleaning, which is easy to do, about every 2-3 months in the winter.

Another really old humidifier for the basement and 1st floor just sits below one of the air ciculator ducts. Don't recall what the manufacturer of it is but certainly does not require much space. It's a Skuttle. Just checked.

On any humidifier, you want to have a regular dump of the water in there. Otherwise, stuff from your water will collect and really cause a cleanup problem. A dump gizmo was put on the old unit. The Honeywell has it built into the logic of the controller. Still, it needs cleanouts more frequently than the old unit that is just a water on/off valve with a ball float and an electric coil in there to boil the water. Quite simple.

Humidifiers can be controlled with a separate humidistat or can use the one on most modern thermostats. Our new one used to have its own controller, but they put it into the new thermostat when we had to replace the upstairs system.

Ralph

 

[dadster4]

A bypass might be your best option. The supply connection can go anywhere on the supply side, but try to install it well before trunk T. If you get it too close to the T or after the T, you could run into moisture distribution issues where a portion of the house isn't seeing the moisture. Make sure you tap into soft water and I'd suggest using hot water. There are direct injection systems (steam or spray), but they seem to demand a higher level of maintenance.

Tapping into hot water is a good idea but do NOT use water softener treated water!
A bypass is the way to go...steam generators are expensive and require more maintenance and replacement of expensive parts on a more frequent basis.
A sheet metal shop can make a fitting to tab into the side of the return drop and flare out to the dimensions needed to mount the humidifier. You have enough room to tap into the left side of the plenum with a 6" round to feed the humidifier, a little aluminum flex will make that easier.

 

[s219]

Tapping into hot water is a good idea but do NOT use water softener treated water!
A bypass is the way to go...steam generators are expensive and require more maintenance and replacement of expensive parts on a more frequent basis.

We've been running a steam unit (Aprilaire 800) for 5 years and haven't had any issues at all. Prior to installing a water softener, I was replacing the steam canister annually at a cost of $55. Since installing a water softener, I have been stretching canister replacement to 2-years, so figure $28/year. The steam units cost more up front, but I like the performance much better than the bypass system we had at our previous house.

 

[lzicc]

My house is about 1500 SF. I'm looking now at the Aprilaire either the 500 or the 500M. I have to install the unit on the return line. Aprilaire, in their directions is saying that the 500 (non manual) needs to be connected to the hot water line. I don't have that option. I just replace my tank hot water heater with a tankless, so I cannot connect it to the hot water side. The Manual one it doesn't specify hot or cold.

 

[dadster4]

We've been running a steam unit (Aprilaire 800) for 5 years and haven't had any issues at all. Prior to installing a water softener, I was replacing the steam canister annually at a cost of $55. Since installing a water softener, I have been stretching canister replacement to 2-years, so figure $28/year. The steam units cost more up front, but I like the performance much better than the bypass system we had at our previous house.

I've installed and serviced hundreds of humidifiers and I'll stand by my statement that steam units will cost more to maintain than any bypass unit. A steam unit may benefit from softened water but a evaporative type will be caked in deposits in no time.

"My house is about 1500 SF. I'm looking now at the Aprilaire either the 500 or the 500M. I have to install the unit on the return line. Aprilaire, in their directions is saying that the 500 (non manual) needs to be connected to the hot water line. I don't have that option. I just replace my tank hot water heater with a tankless, so I cannot connect it to the hot water side. The Manual one it doesn't specify hot or cold."

You can still tap into a hot water line close to your heater or a hot line which is used often...it will provide enough hot water to make it preferable over a cold water line, even though the heater itself won't cycle.

 

[coldsteelva]

In houses with traditional water heaters that have long runs to the furthest faucet, it is possible to install a crossover that allows you pull hot water from the tank (flowing back through the cold line) so as not to waste water down the drain while waiting for the hot to arrive.

Could a similar crossover be installed near the outlet/inlet of the tankless, triggered by a signal/relay from the humidifier, so that enough flow through the tankless to trigger heating occurs and thus providing nearly instant hot water to the humidifier feed line?

 

[lzicc]

I could install a re circulation pump, but that concerns me that the tankless hot water heater would run more than it should. I also can't seem to find good information on one for a tankless water heater. Rheem makes one, but you have to have a return line from the furthest fixture which I don't have and would be to difficult to install one since the walls and ceiling in the basement are finished.