high humidity in my house
Comments
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10 on and 50 off is your issue. Not enough run time to drop the RH.
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Is this the HRV or the AC? Those're fine times for an HRV, but not for the AC.
Also, heat recovery (HRV) or energy recovery (ERV)?
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Good question.
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outdoor temp and humidity depends on time of day but the low is 13 f and high would be 90f
and rh is anywhere from 50% to 80%.
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Let me clarify the question.
Ventilation will only reduce the humidity indoors if the absolute moisture content of the outside air is lower than the moisture content of the inside air. If the opposite is true, ventilation will increase the humidity indoors.
Relative humidity, as it names implies, is not a measure of absolute moisture content, it's a temperature-dependent measure. The easiest measure to use is dew point. So ventilation only helps reduce humidity when the dew point outside is lower than the dew point inside. In most of the US, in weather where you would be running air conditioning, the outdoor dew point is higher than the indoor dew point.
The reason I asked about the outdoor conditions is that dew point can be calculated from temperature and humidity. What matters is not the range over the course of the year, but at the instant you're running the ventilation.
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is your system cycling off and on. How long does a cycle run in your system. At a 69 degree return air temperature I don't know how much humidity you expect to remove if your system is cycling off. How low do you set your thermostat. if I was to guess you might have an over-sized system which is great at lowering sensible heat but not much latent heat, which is where all your dehumidification happens.
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69 return if the unit is cycling on temp too much it will never lower RH enough. You may need reheat but that is expensive to run a bigger 9thicker coil is better.
I asked this before: With the water and air temps you have it this coil dumping a lot of water? It should be, and is it dumping the water outside the house?
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clarify what's running 10 and 50, the AC needs to be 50 on, and maybe 10 off, to dehumidify,
8 systems running off the chillers, sounds over sized, which is the worst thing you can do with AC / Dehumidification, how big is the place?
this seems to be an "Engineered" system, with bells and whistles, is there by chance a HUMIDIFIER for the winter season? and is it shut off?
known to beat dead horses0 -
In my experience I find that if HRV vents are at ground level (say if the HRV is in a basement) all they are doing in the summer is bringing in high humidity ground level humidity that defeats the AC system. Where I've found such systems I've asked the customers to turn off their HRVs anytime the outdoor temperature is above 50 degrees and to use them only when needed and only for as long as needed. They are intended to help control humidity and provide some heat exchange for fresh air make-up. However, in regions with high summer humidity they can easily over-ride conventional AC equipment and introduce high humidity air 24/7 if left running.
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HRV’s have no way of lowering RH. If it’s raining and cool out the indoor RH will go up
A whole house dehumidifier with outside air hookup is a much better option.
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I think that where people get confused is that HRVs — or air conditioners without condensation, or shade, or whatever — do not change the actual moisture content of a volume of air — measured most conveniently by the dew point. Relative humidity is the relationship between the dew point — at which temperature the air mass holds as much moisture as it can without condensing — and the sensible air temperature, as measured by a normal thermometer. If you lower the sensible temperature, the relative humidity increases. Raise it, and the relative humidity decreases.
The only way you can lower the relative humidity at a given sensible temperature is to cool the air enough to lower it below the dew point, at which some of the moisture will condense out, and then warm it back up to where you want it.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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Imho high velocity and dehumidifying are two words not to be used together. I dont have any experience with unico type systems or any newer residential systems (i work comercial)but what is your cfm/ton of cooling? And where are you located? Bringing in outside air with an erv has to be designed very carefully and in very humid climates is almost always a nightmare. You have a very inefficient and from what it sounds like ineffective system designed here. Wondering why this is the route you or someone else chose for your home. Im many areas of the country reheat is no longer even allowed to be designed into new installs with few exceptions but none of them being residential. You need to be careful playing around with your chiller. Make and model of chiller would be helpful. You cant run the water temps down that low safely without a glycol mix. And there's no need for chilled water below 42f in any building for comfort cooling. Your water flow is too high rite now, how is the flow controlled? Dp? Your chiller must be cycling alot which is not good for it. You should have return water in the mid 50s for most conditions. As your return wtr temp drops below that your chillers efficiency reduces as well,and quite a bit too. You already have one of the most inefficient residential setups I've ever heard about, why not try to get it all running correctly? What I would do is focus more on keeping humidity out of the building rather than trying to remove humidity once its entered. It's a house, not a school or office building where the setup you have is common due to ventilation requirements. Why not just run the fresh air intake only when its needed, have it interlocked with exhaust fans and dryer. Pretty easy to do with a relay and a few ct's you should be able to run 42-44f supply water sp. With no reheat needed if everything was designed and sized correctly.
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HRV’s do not remove moisture.
A better solution is a whole house dehumidifier with outside air hook up.0 -
Possibly your issue is that your HRV/EVR is tied into your existing hi vee system . Personally i would have designed the hrv/erv as a separate system avoiding running the hi vel system fan for distribution being i have read some articles written by manufactures who suggest over all that a dedicated system for either is a much more eff and better designed system then slapping it in to the existing it into a existing duct system . Basically the cheapest way to do it . Being usually running just the fan does lead to a high humidity level . Also the extra waste of electric wasted to power both units and the dilution of air exchange especially when tied into a high velocity system ,i ve looked at the same type of install being your using two completely different type of air flow system hi static hi velocity and a low static low air flow some body did not do there due diligence nor possibly speak to either manufacture for any idea for correct installation . I also do believe if remembering correctly that a longer cycle time is required when tied into a existing duct system to get the required air exchanger you are hoping for which in turn means elevated humidity unless the cooling is calling .
AS for water temps and flow if the original contractor was skilled enough and familiar enough w what he sold and installed this would be a no issue install . All looks great when slick tongues are at work until issues appear from there own short comings of the understanding of basic design and common sense also w reading and under standing what you are reading and follwing it through w installing and the interplay and of course cause and effect of ones actions
I ve looked at installing both for clients and both times i walked being they wanted there way which i was not interested in doing and wanted to CMA so i left for some one else .lol .Also everyone wants everything jammed some place where no one could ever possibly see or service or want to . Other note to self if they aint calling you for maintenance of there heating and cooling what makes you think they will do anything except complain when it has to be service ?nothing
peace and continued good luck clam
R.A. Calmbacher L.L.C. HVAC
NJ Master HVAC Lic.
Mahwah, NJ
Specializing in steam and hydronic heating0
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