>> Yesterday and today I had to run both heat and
>>>AC, that is the only way to deal with the exceptional
>>>high humidity both days.
>>
>>No. It would be more energy-efficient to run a dehumidifier when
>>you need heat and an AC when you need cooling,
>
> The temperature was ok, I don't have a dehumidifier,
Put one $80 AC in a window and one in the house. Wire the window AC to the close-on-rise contact of Grainger's $16 2E158 SPDT thermostat and the other to the close-on-fall contact. Run the common contact to Grainger's $31 2E453 (Autoflo 052000) humidistat.
and warming the air lowers humidity more efficiently than a dehumidifier.
Warming air lowers the RH, but it doesn't remove any water vapor.
I run a humidifier anytime the outdoor temperature
>is below 40 degrees...
Your house needs air sealing.
moist air feels warmer than dry, and
>a steam humidifier is efficient use of heat.
Winter humidification uses about 10X more heat energy than it can save.
It is rare to have 90 percent humidity in the house,
>and the quickest way to reduce it to improve breathing
>is likely the most efficient.
Hey, a new rule of thumb: "the quickest way is the most efficient" :-)
Thanks for the off-the-shelf engineering, but this was a one day thing.
Relative humidity is the important thing, the amount of moisture in the air is meaningless, the amount of water the air can hold relative to the amount of water in the air is relative humidity.
Not really, the sensitive membranes in my nose need sealing.
And that is one of the reasons I try to avoid using the Cozy space heaters, they change the air in the house very often, and even warn that space for incoming air be provided.
Not a chance, the few hundred watts the humidifier uses simply replaces the electric baseboard heat used.
Any house that needs winter humidification needs air sealing.
Houses leak air. Especially your house :-) Lennox stopped advertising that winter humidification saves energy after I convinced their engineering VP that it uses 10X more than it can save.
You need to study more about relative humidity, and about the differences in people's nasal passages. I would not be able to use the Cozy space heaters if I sealed the house, they need to draft up the chimney. Maybe you are too young to have seen a furnace that uses indoor air for the flame?
Energy used is not even an issue with my nose, and I have decades of experience with it.
Your number of 10 X is so absurd that it would be laughable if you were not contaminating minds.
It is essential that the air in a house is changed at least every 2 or 3 hours, and much more often with some kinds of heating appliances.
A major factor in my decision to try to get by with electric baseboard heat is the reduced number of times the air in the house changes in 24 hours, because one Cosy stove has the flue pipe removed and the flue blocked (and nailed shut to keep the chimney birds in the chimney). And I won't light the pilot on the other stove until the temperature goes below 20 degrees F.
It is 111 years old, so what else is new?
How did you do that, with BS or numbers?
I don't like the fan humidifiers, they need a chemical added to the water and the water changed every day. It is easier to change the water with a steam humidifier, and as long as I am using electric resistance heat anyway, your number does not apply, no matter how low you revise it.
If doctors were to advise patients who get head colds every winter to humidify when the outdoor temperature is below 40 degrees F, the number of head colds would be reduced by at least half, and maybe as much as 80 percent less.
For those who may have believed your mistaken opinion, I will explain why indoor air relative humidity drops dramatically with lower outdoor temperatures, and why humidifiers make it seem warmer and why temperatures are more stable with 50 percent relative humidity indoors all winter.
The air in all house changes, and there is a definite number of times it needs to change, the type of heat determines that, but a house should never be sealed so tight that it takes longer than 3 hours to change completely. (Check the furnace or heater instructions).
As the air changes, outdoor air that has a relative humidity of 40 percent at 30 degrees F that is warmed to 70 degrees F undergoes a change in relativity humidity according to well know charts showing how much water air at those temperatures can hold.
At lower outdoor temperatures and lower out door humidity, the indoor humidity can become very low, as low as 10 percent or less, even without any removal of water vapor.
Warm air __CAN__ hold more water, and cooler air can only hold so much less, and that is why _relativity_ changes when outdoor air replaces indoor air in winter.
This is a health issue, for a large number of people, while others have no problem at all with head colds or sore throats in winter. It is not an energy efficiency issue, not a home repair issue (as long as health comes before minor moisture damage), it is not a frugal living issue if the doctor visit costs more than all other associated costs, and it is not a homepower issue, it is a health issue, so I don't know why even a trouble maker like you would crosspost so many groups. :-)
I already posted the effects of low relativity humidity on sensitive nasal membranes, and already posted the explanation of how moisture in fabrics in the house is drawn from the fabrics as air dries, carrying germs, and is breathed, and the germs are able to get a foothold in the nasal membranes of people who do have that sensitivity problem. So a shallow consideration of only energy used and it's effect on air temperature is not pertinent.
But moist air carries more BTU per pound than dry air, even though moist air occupies more space per pound. Between cycles of the furnace, moist air resists cooling more than dry air in the same period of time. And warm moist air feels warmer than warm dry air, although this is pretty much a personal judgement issue. (Moist cool air feels colder than dry cool air).
All this together makes your meddling in the marketing practices of a company with decades of experience in heating and cooling, despicable, in my opinion. When I had a house with central air, I bought and installed a self filling humidifier from Sears, and it make a big difference in comfort at the same temperature settings.
So study about relative humidity, how warming air changes the relativity without any change in the amount of water it contains, and the harmful effects that can have on the health of certain people. And also study how air too dry can damage furniture, woodwork and other materials, just as much as air too moist.
You might find it so, but the experience of a lot of us who have moved south gives it a lot of credence. In Vermont, I used to get at least four colds a winter. In the humid south, catching a cold is a rare event for me.
I don't necessarily agree with the theory as to why, but I do agree with the posit that proper humidifying can reduce the misery of moving from one cold to another.
People who do not get head colds will not be able to test it. The action of moisture changes and migration out of fabrics is very complex, and doctors are trained to treat the human body, not to try to understand every chemical, physical or other discipline.
I never had any problem with my nose (head cold) in Las Vegas all one summer back when relativity was below one percent there when the temperature was greater than 110 F.
But when I rented a pool house in Pasadena in January and it got down to 33 degrees one night and I turned on the gas wall heater, I got an awful head cold.
This gives the head cold sufferers something to try, steam humidifiers (vaporizers) are available at Walmart for less than $20, and I would give $20 any day not to get a head cold.
I don't have to pay for doctor visits, but many people do, so saving that expenditure is worth some effort.
Every September when the kids go back to school we all get colds. I don't think fiddling with the humidity in the house is going to change that. Besides for 9 months out of the year the humidity here is nearly 100% in these parts and those are the 9 months we are all sick. Currently it's 57 °F with 77% Humidity (the sun is shining) and we all have runny noses from head colds.
I'd say always. Andersen says an average family of 4 puts about 2 gallons per day of water (16.7 pounds) into house air. In an absolutely airtight house, the RH would rise to 100% near windows with wintertime condensation.
ASHRAE says houses need 15 cfm of fresh air per full-time occupant, so
4 half-time occupants need 30 cfm at 0.075 lb/ft^3, ie 30x60mx24hx0.075 = 3240 lb/day of fresh air. January outdoor air in Phila has an average humidity ratio wo = 0.0032 pounds of water per pound of dry air. If minimal ventilation with no condensation removes 3240(wi-wo) = 16.7 lb/day of water from the house, wi = 0.00834, and 70 F air at 100% RH has w = 0.0158, so the house RH would be about 100wi/w = 53% with minimal ventilation, or more, with a small efficient air-air heat exchanger with outgoing condensation.
Keeping the RH 60% (wi = 0.00948) means condensing 3240(wi-wo)-16.7 = 2.03 lb/day (2 pints) or 0.085 lb/h of water from the outgoing air, with a latent heat of 1000x0.085 = 85 Btu/h (about 25 watts--not much), ie lowering the outgoing humidity ratio to 0.00834 at 100% RH, ie lowering its temperature to about 52 F. If we recover 90% of the heat, E = 0.9 = 1-e^-NTU, so the Number of heat Transfer Units NTU = -ln(0.1) = 2.3 = AU/Cmin, where A is the heat transfer area in ft^2, U is its film conductance in Btu/h-F-ft^2, and Cmin is the heat capacity flow rate in Btu/h-F.
U = 2 and Cmin = 30 make A = 2.3x30/2 = 35 ft^2, so we might preheat incoming 30 F outdoor air with a small fan pulling outgoing 70 F air between 48 1'x1'x1/8" Coroplast sheets in a 1' cube with A = 96 ft^2 and NTU = 6.4 and E = 1-e^-6.4 = 99.8% heat recovery. The condensation might drip onto a large green plant that re-evaporates it.
An average US house naturally leaks about 200 cfm. A 2400 ft^2 house that meets the Canadian IDEAS (post R2000) standard would naturally leak 2.5 cfm.
Is it when the kids go back to school, or when the heating season starts?
Maybe not, there are other reasons for head colds, that everyone may be subject to, even if humidity is ok, chills, not enough sleep, close contact with others who have colds.
The outside humidity doesn't matter, having heat on in the house does.
Makes me feel bad just to hear about it.
I try to stay away from people with colds, but that would be difficult for kids in school. While I would like to use as little heating fuel as possible, I feel comfort and health are important, so I keep the house warm, and I don't usually worry about humidity until the temperature goes down to
40 F, and even then, I only run the humidifier at night as long as it stays above 10 degrees F.
Trying to get by with too little heat can cause more colds, but once it starts, there is no way to tell what caused it.
I had a weightlifter friend who never had a head cold, until we stayed up all night playing cards, and that did it, at least that is what he blamed it on.
Maybe I should have mentioned, it is the changes in humidity that cause the problem, being that I always humidify when a humidistat shows it needs it, I don't have the big changes in humidity.
Even in a spic and span clean house, the changes in humidity can cause problems, almost everything from expensive furniture to fabrics last longer if humidity is kept at a constant 50 percent RH, although experts may recommend 40 or 45.
It should be worth discussing with the family and see if each one has any ideas on where or what causes each cold, I know I am completely miserable, even totally incapacitated from it at times. Some people can go outside in shirt sleeves in
50 degree weather, but not me. If the water is changed daily in the Vicks vaporizer in my bedroom, it only costs me about $12 a year to buy a new vaporizer. Doctors will recommend a vaporizer after a person gets a cold, better to get the vaporizer before the cold and save the doctor bill.
Actually it's more complicated. Partial pressure of water vapor in air and the partial pressure of any standing water determine evaporation/drying rate. Human sinuses have 'water' that stays at the same temperature (unless you're running a fever), so the partial pressure of water vapor in air is pretty much it. And the pp of water vapor is saturation pressure for the dry bulb temperature times the RH. Heating air doesn't change the pp of water vapor (saturation pressure rises as much as RH drops).
Surely you've noticed that running the heat up high in the winter doesn't do anything for your sinuses. Humidification (raising the pp of water vapor) does.
Trouble is, the partial pressure of water vapor is not readily measured. It can be calculated from RH and dry bulb temperature. (find the saturation pressure of water at the dry bulb temperature, then multiply by RH). The next best thing is to track the dew point. When you heat air, the dew point doesn't change. Hot air is better at drying 'things' because the hot air provides more energy to evaporate the liquid.
This winter, rather than track the RH as my house temperature rises/falls (set-back thermostat), I plan on tracking the dew point. I suspect it will give me much more consistent data.
It's not just the electric to power the humidifier, it is also the energy to evaporate the water. With many simple humidifiers, that energy comes from the air blowing through it. So the furnace works harder to heat the air back up again.
Yes, it's certainly more comfortable (I have problems with wintertime humidity as well). And the human body 'feels' comfortable when the heat losses through convection and evaporation are matched to our optimum value. Lowering evaporation heat loss (by raising the dew point) can allow for slight increase in convection losses (setting the thermostat down a degree or two). But it's very subjective.
Here in NY, when the kids go back to school you can bet on them catching colds. Before the heating season starts. Just all those kids confined in a classroom for 5-6 hours, with some individuals with questionable hygiene almost guarantees it.
But the 'heating season' does have a contributing factor. Less ventilation in a house means virii are not dispersed as quickly.
And although I haven't seen any definitive studies, it does seem that dried out sinuses are more susceptible to infection. But that's just my own anecdotal observation.
There ain't none o' them thar virii on my house!
I wish I could say it isn't so, but I have done 75 years of definitive study of a nose making what sometimes seem like a gallon an hour.
One way that I reduced the severity and length of the cold is to use bounty towels instead of hankies or Kleenex, and it helps keeping the nose from getting so red and sore, I only use each one once and throw it away.
It sounds like you and Nick did not appreciate or understand what I posted about the absorption and emission of water vapor from carpets and fabrics.
And there is a huge difference in noses, some (me) actually have capillary bleeding if the air gets too dry, sometimes a cold follows, sometimes not.
I can feel the drying of my sinus in a 20 mile trip in the car with A/C set to 70 degrees on a hot day.
The problem is, studies may not show anything definite about the nose, and the "disease" is not considered serious enough to warrant serious study. But I am surprised there is not definitive data on the drying of expensive wood items, especially antiques and artifacts.
So any company that sells humidifiers should keep on selling, and advertise what they do for wood and fabrics, if not for people or noses. I don't have any fine wood items, but I have a nose that has a lot of influence on my H, V, and A/C.
Maybe it would be nice if you could share a little of your open mindedness with Nick. :-)
Sorry, Doctor, there may be colds that are "caught", but mine come from inflamed sinus irritated by dry air.
Glad you have such faith in articles written by just anybody who wants to write or modify them.
The only old-wives tale I know of about dry air is "sleep with the window open". I tried that one night in a hotel in Lorain Ohio in the winter of 62-63 and woke up with eight inches of snow on the bed.
That's right, it was a long cold war, too, but thankfully not many on either side died in battle.
I am sure it is, I wondered about it ever since I saw a meteorologist put cotton on a thermometer and swing it round and round in 1946.
Sure, but breathing through the nose moves a lot of air over the same tissue. I won't go into Bernoulli or Venturi.
Please don't say that carpeting doesn't dry out if wet. :-)
It sure does, it makes them bleed, and feel like the tissue is stretched. Then a few hours later they start producing moisture.
And you base this on the next sentence?
Try running a cool air humidifier, and see that it stops evaporating water after a certain humidity. I use a steam humidifier so I can go to higher RH.
Yes, I have read many of the papers by Einstein on specific heat and latent heats.
You are more of a scientist than I want to be to keep a nose dry. :-)
Which is another reason I use a steam vaporizer, I try to put at least 2 gallons of water in the air on a cold night, and I only do this in my room, the rest of the house doesn't matter.
I really need to avoid colds and trips to the doctor.
In order to try to conserve (prompted by the rise in retail natural gas last fall), I am only heating my room, the kitchen and the bath. I wouldn't heat the kitchen but I can feel the convection drafts as the cool air moves into my room.
I really should build a balcony in my room and put the bed and computer and TV on it as I have eleven foot ceilings. I bought some 36 inch balloons that I am going to fill with air (not helium, I talk funny enough now), and put screw-eyes in the wood strips on the ceiling and pull them up with a string, and if the air leaks out I will be able to let them down to fill them.
Every house and every person is different, my house was designed originally as two large rooms with a double fireplace in the common wall, and if it were not for that fireplace, the house would have floated away when the river was up to the peak of the roof in January 1937.
Houses with working fireplaces can't safely be sealed air tight, even if air tight is just a figure of speech.
Actually, the faster the air changes, the higher the relative humidity may be )without a humidifier), I really haven't considered that though, I need it warm, and I want to conserve in a reasonable and rational way.
If you need to know how much moisture is in the air then you need to know the (GRAINS PER POUND) of water in the air. You can also use the dew point if you know what you are looking for but the GPP works better.
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The formula is on the page above. We have special equipment at work that does the math for you. They also make slide rule or disks that you can set to the temperature and the RH that will give you the GPP.
You can also buy (LGR) low grain refrigerant dehumidifyer. They come really close in removeing moisture compared to desicates. Take a look at
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There is some links there for dehumidifier manufacturers.
I hope this helps..
Joe IICRC Water Restoration master. Yes I dry out buildings for a living...
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