Honeywell Humidicalc Recommended Instead of Outdoor Sensor? (Automatic Humidity Control)

[Smarty]

Nick,

Here we go again.

For starters, had you replied to the original poster's question, and had you done even the slightest amount of research before expounding on how external wall temperatures were being used by the Humidicalc, I would have respected you.

Maybe 40 years of professional engineering seems like an old man's tale to you since you find it necessary to mock my experience, but I am here to tell you 2 crucial and basic things which you apparently have not been taught yet in your Villanova engineering program which were basic to my engineering education and even more important to my eventual success in managing thousands of engineers in a large aerospace company:

1. Listen to the stated question, in this case how do 2 humidistats compare, and reply to it.

1. Do the research..........and only then offer an opinion. A 90 second Google search would have revealed to you (as it did to me) that the Honeywell Humidicalc humidstat is a duct-mounted device, is *** N O T P L A C E D O N A N E X T E R N A L WA L L *** to indirectly measure outdoor temperature, and furthermore, actually needs an outdoor Honeywell temperature sensor to be installed in some circumstances. You would also find that Aprilaire and other duct mounted humdistats with outdoor sensors also have the very same "Frost Control" to apply manual feedback, and thus the Humidicalc has absolutely nothing novel or different in this regard, contrary to your unresearched opinion. Offering this group an uninformed and unresearched position such as you did damages your credibility.

There is a 3rd rule which is never taught in school, but is simple basic manners. Don't rely on name-calling. It looks and is childish, and undermines the integrity of your thinking process and your up-bringing.

It gives engineering a bad reputation when its' trained practitioners ignore the question, provide the wrong answers based on opinion rather than published facts, and use name-calling as a discussion tactic.

Smarty

[nicksanspam]

My thinking process is fine, thanks :-)

If your average US house naturally leaked 224 cfm on an average 30.4 F Philadelphia January day with an outdoor humidity ratio wo = 0.0025, how would the fuel consumption change if you

a) airsealed it to reduce the natural air leakage to 24 cfm, or

b) humidified it to 50%, with no airsealing?

Your thinking process doesn't seem up to these simple calcs, even with 2 engineering degrees. Consider your bluff called. Perhaps you should give up now :-)

Nick

[nicksanspam]

This way, you can raise the RH to 50% and reduce the fuel consumption by about 24h(70-32)200 = 182.4K Btu/day, saving something like 2 therms of gas or 2 gallons of oil per day.

This way, with no reduced air leakage savings, the fuel consumption INcreases by 24hx224x60x0.075(0.00787-0.0025)1000 = 129.9K Btu/day.

The difference is 312K Btu/day, over $6/day at $2/therm.

Nick

[Smarty]

Nick,

As earlier, you want to answer your own question and not that of the poster.

Since you think I am, to use your word, "bluffing", I will answer your digression. It is patently obvious without doing the "calc" as you call it that a sealed house will require less evaporation energy than an unsealed house. There has never been either a question or a dispute in this regard. An order of magnitude drop in water / evaporation energy consumption occurs when a corresponding order of magnitude drop in air leak takes place (from

224 to 24), and the exact water used / evaporation energy delta depends on what assumptions you want to make about desired indoor temperature and desired indoor humidity, neither of which you specified. For 70% indoor temp and 30% indoor humidity, you avoid evaporating about .09 gallons of water per day with the correspondingly tiny drop in energy consumption.

Conversely, if you wanted to raise it to 50% humidity inside, you need more water / energy, the amount of which is again determined by what initial indoor temperature and humidity you specify. Since you do not specify the initial amounts, I used 70% and 30% once again, and, on this basis, see an increase of .15 gals of water to be evaporated per day.

I have no desire to discuss or debate with you the relative merits of airsealing versus active humidification, and indeed this is the digression for which I previously apologized, even though you were (and continue to be) the one who pushes for it in this thread.

Enough of your nonsense!

*****Plonk*****

Smarty

[Lin Kwang]

Very wrong analysis. 312K Btu/day would evaporate almost 40 gallons of water per day (~8000 BTU/gallon). This is many times more than really evaporated. Savings are much smaller.

[nicksanspam]

No. The choices were a) airseal, reducing the existing fuel consumption by about 2 therms per day, or b) humidify, increasing the existing fuel bill by about 1 extra therm per day, with no airsealing.

You might reread that posting.

Nick

[nicksansouci]

Wrong problem :-) I asked:

but Smarty talks about airsealing WITH humidification, which isn't needed, given enough airsealing and natural indoor humidity sources like people and green plants, but let's solve the problems he poses...

Smarty measures temperatures as percentages? :-) On my planet, 70 F air at 30% RH has a humidity ratio wi = 0.0047 pounds of water per pound of dry air, so keeping a 224 cfm house 70 F at 30% with an outdoor humidity ratio wo = 0.0025 requires evaporating 224x60x0.075(wi-wo) = 2.22 pounds of water per hour or 53.2 pounds of water per day, ie 6.39 gallons.

A 24 cfm house requires 0.68 gallons per day, and the difference is

5.71 gallons, at an energy cost of 47.5K Btu/day, about 0.5 therms, or $1/day at $2/therm.

So Smarty is perfectly capable of providing different wrong answers for the same 70F/30% problem :-)

When a man is wrong and he won't admit it, he always becomes angry :-)

Nick

[poster3814]

Thanks again for the replies. For what it's worth, I'm going to start a new message thread that is somewhat related but not totally related.

[Smarty]

poster3814,

Your reply to the numerous comments from me and others never indicated any opinions or conclusions on your part as to which of the humidistat approaches you prefer. As I imagine you are aware, both the Aprilaire and the Honeywell humidifiers can be used with other humidistats, and in fact the Aprilaire humidifier could be used with the Honeywell humidistat or vice versa. I bring this up because you may not be aware of this based on your more recent thread, once again comparing Aprilaire to Honeywell.

In an earlier reply I did indeed make a mistake, and erroneously typed a percent sign % when I intended to type a notation for degrees °. I think it was still apparent that my references to temperature and humidity of 70 and

30 respectively were pretty obvious despite the typo. Sorry for the wrong keystroke.

Smarty

[trader4]

Heh, Smarty, just a side note. I didn't see your interchange with the genius from Villanova until today. Just wanted to say, like others here, I agree with you. He's well known for hijacking threads. Someone asks a simple, practical, real world question and he answers with equations and calcs trying to show how smart he is. But in reality, all he shows is that he has a complete lack of practical experience. He thinks because he has an equation, means it's applicable to the question or that someone can re-engineer a 50 year old house. The reality is, he couldn't even install a humidifier and just gives V a bad reputation.

[nicksanshonte]

Let's not forget your 100x6.39/0.09 = 7100% computational error :-)

Nick

[Smarty]

trader4,

Your kind comments are very much appreciated. Because I am a retired engineer and have worked with literally thousands of other engineers in my career since the 1960's, I do especially dislike a simple technical matter becoming complicated when it doesn't need to be, and a specific technical question being answered with an unresearched and inappropriate answer. The fellow at Villanova U. was asked about comparing humidistats, and replied with clearly wrong information on a distantly related subject, and then assumed the Honeywell could somehow magically infer outdoor temperature by being mounted on an external wall even though it is clearly a cold air return plenum mounted device with no physical proximity whatsoever to the periphery of the house.

It doesn't take an engineering degree to know or use the equations he mis-applies, and either psychometric charts or simple spreadsheet/calculators are used by ASHRAE heating/cooling consultants and contractors all the time to size these equipments.

I actually think the gentleman at MIT said it best when he corrected Nick at Villanova by saying:

"Very wrong analysis. 312K Btu/day would evaporate almost 40 gallons of water per day (~8000 BTU/gallon). This is many times more than really evaporated. Savings are much smaller."

I apologized once before to this newsgroup for the digression and confusion which arose, and do so once again now. I sincerely hope we can get the original poster to be both well informed and fully comfortable with the choice of a new humidifier and humidistat per his/her stated inquiries.

Smarty

Heh, Smarty, just a side note. I didn't see your interchange with the genius from Villanova until today. Just wanted to say, like others here, I agree with you. He's well known for hijacking threads. Someone asks a simple, practical, real world question and he answers with equations and calcs trying to show how smart he is. But in reality, all he shows is that he has a complete lack of practical experience. He thinks because he has an equation, means it's applicable to the question or that someone can re-engineer a 50 year old house. The reality is, he couldn't even install a humidifier and just gives V a bad reputation.

[Smarty]

psychrometric replaced by my spell checker with psychometric...sorry

[nicksansteeth]

I applied. Smarty misapplied, with a 7100% error :-)

Airsealing and humidification can both raise the indoor RH, but airsealing lowers the fuel bill and humidification raises it.

Nick, enjoying repeating obvious truths to people who won't listen.