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Adding Humidity, Part Deux

So, let's say you have a house with an AC system and radiant floor heat. The current humidifier is a Nortec residential unit which makes the local utility very happy. What are the pros and cons of rival humidification systems that can work on systems without warmed air?

For example, I have considered a Herrmidifier 707 which atomizes droplets and allegedly does not require a warm duct system. The only downside that is really apparent is the need for clean or distilled water to keep deposits to a minimum. However, I have no experience with the unit and who knows how effective it is when the air is only at 70*F...

Any help would be appreciated. Cheers! C.


  • don_9
    don_9 Member Posts: 395
    Adding humidity

    Goodmorning Constantin.I thought i read over the years that your home was very tight.i also assume from reading your threads that you were bringing fresh air in the home with a life breath or something like that.

    See my issue with that would be if you have a very tight home then one would have no need to add to the humidity..your issue would be more of trying to get rid of it.maybe you would want to monitor your home for acouple of weeks and see if you really need a humidifider at all.You may even find that the air exchanger is is not being controlled properly or that its just another piece of auxially equipment that looks good to mr jones..Look into the telaire 7001 its measure co2 and ventilation rates.monitor your co2 numbers and adjust your fresh air into the home from your co2 numbers.

    Stay away from any of the  atomizes humidifider they are nothing but trouble.

    Yes you have to love the steam humidifider when dealing with low discharge air temps.But you sure hate the power bills when they arrive.Makes me wonder why one would even need a humidifider in a tight home with infloor heat.

    Good luck with your search.
  • Constantin
    Constantin Member Posts: 3,796
    Hi Don...

    Well, the house certainly tested out very well. I don't recall the exact ACH, but they were fairly low. What the test does not emulate very well though is the very high wind load that the house experiences on account of the location (top of hill). We have some pretty significant exfiltration issues around the old windows, resulting in condensation on affected storm windows and icicles hanging off the exterior trim below the storms.

    I have tried to limit the impact of said infiltration by retrofitting storm windows even over modern replacement windows on the side of the house facing the prevailing wind - which has helped reduce but not eliminate the issue. The lesson here is that as much as I may love "old" windows with their wavy glass, etc. there is a price to pay and exfiltration is the most obvious symptom. Similarly, keeping two fireplaces in the house was a luxury that is not necessary and that won't save us any energy either... and limiting ex/infiltration via external dampers helps but does not eliminate the problem.

    A HRV is a similar luxury in this house, since natural infiltration pretty much covers occupancy needs unless the place is packed. Over time, I noted the impacts of running both HRVs, determined that only one of them was needed at best (the smaller one). Hence, I relegated the bigger one to bath fan duty. Not ideal, but until one educates oneself about these things... Anyway, the big HRV comes on only when the occupancy sensors in the bathrooms register an occupant. However, due to the logic controller that Lifebreath/Nutech ships with it, the external signal for on/off only results in the thing running on the equivalent of high-fire. Not great at night, etc. due to the noise that generates.

    Having spoken to some of the great folk at Nutech, I've come to the conclusion that I have two options re: this HRV: 1) turn the unit on constant low-speed fan mode, then use the relay in the occupancy-sensor system to turn the motor on/off (that is, interrupt the line that runs from the auto-transformer) or 2) have some fun with an Arduino, a variable-speed PSC motor controller from Vardigm, etc. Being an engineer, I chose option 2).

    The arduino will give me the option to control the thing more flexibly - i.e. keep the fan running on low speed until the bathroom exhaust RH is within the same range as the ambient RH, run the thing on higher speed if multiple bathrooms are occupied, etc. Additionally, I can use it as a datalogger - though this capability will be enabled at a later time since communicating independently from an Arduino is a lot trickier than setting up a simple control logic to keep a HRV happy. Lastly, I am not going to worry much about the defrost damper - that will be more of an issue with the other HRV that actually runs 24/7 on a 40/20 cycle.

    So I think I am starting to get my hands wrapped around the issue of the fan control. The humidification is another matter, however. The original install used a separate actuator (horsehair) to interface with the logic relay in the Nortec. The Nortec was then connected to the air handler in some strange fashion - I think the idea was to create a "G" connection to get the fan going - instead of connecting the humidifier output to the right input on the Harmony II zone controller. Among other things, that approach led to some strange back-emf or somesuch, making the Harmony II Y1 and Y2 contacts light up whenever the humidifier was running. I fixed all that by upgrading from a Harmony II to a Harmony III, removing the excess wiring, and making the changes to the air handler control board that the Harmony III install calls for.

    One of the nice things with this approach is that individual zones can now call for humidification. However, I suspect that the steam outlet wand was placed into the trunk of one of the zones rather than the main trunk, leading to that zone always having way more humidification going into it than other zones in the house. That is something I will have to investigate with a bore scope, since the wand is 100% inacessible right now. However, it makes sense! Thanks for the link and your thoughts, and I apologize for the long reply, I hope it was amusing. Cheers!
  • BillW
    BillW Member Posts: 198

    Hi!  Sorry about the delay in answering.  I agree with Don that you may not need supplemental humidification, if your house is tight.  Showers, cooking and laundry put more humidity into the air than you might think.  I do not recommend atomizing humidifiers, the orifice that the water sprays thru is absolutely critical, and any wear or mineral deposits or water pressure variations can result in droplets coalescing on the duct, leading to serious problems.  In general ER/HR  units should run on low speed 24/7.  Bath occupancy sensors or manual overides to start them into high speed are one approach, and you also can program them to run at different times and speeds with certain thermostats.  I'm suprised that the ER/HR unit is loud.  Usually, they run at about 200 cfm, and are barely noticible. For low temp systems, steam humidification is probably the best option, despite electricity consumption, which actually should be reasonable, if the unit is sized properly, and your controls are working right.  I hope this helps.
  • don_9
    don_9 Member Posts: 395
    Hi Constantin

    Sounds like you have a great handle on your house.Wish i could deal with a customer like you on a given day.I'll bet you have a very hard time getting control up on that hill.i like it down at sea level myself much more forgiving.LOl.

    Thanks for sharing.
  • NRT_Rob
    NRT_Rob Member Posts: 1,013

    maybe the best option is to hold on to the humidity you already have, with an ERV instead of an HRV?

    we're running an UltimateAir Recoupaerator in our new shop. 40-250watt ECM up to about 200 CFM max. it's not silent, but it seems to do a good job on the exhange so far.

    downside is in cold weather boost heat for the incoming leg is needed. I'm told this is a very small amount of energy. I'll be recording next winter...

    but it does have very high exchange efficiency and might make the difference between needing added humidity, and not. it can even be fitted with pressure transducers to maintain very slight positive pressurization, so you might get some more control over that exfiltration issue... maaayyybbbee...
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • Constantin
    Constantin Member Posts: 3,796

    ... the lifebreath 30TRV actually contains a ERV as well as a HRV core. So, I should be good. I like the stirling product, but IIRC it won't fit in the present space. Wall legend Jerry Scharf made me aware of it, alas too late for this project (at least upstairs). Speaking of which, I miss Jerry and hope he is well.
  • Constantin
    Constantin Member Posts: 3,796
    Only a couple hundred feet above you then...

    ... just happens to be the highest point in the people's republica of Cantabridgia. But a hill is a hill and wind speeds tend to be higher up here.  And now back to the gulag, aka digging out my electrical service.
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