Constant-temperature dehumidification

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On 21 Sep 2006 06:20:35 -0400, snipped-for-privacy@ece.villanova.edu wrote:

Furniture needs constant humidity, whole system efficiency cannot be based on minimum regulations or standards.
Efficiency experts are driving a lot of companies out of business with bad advice, reduced inventories, reduced hours, and eliminated services.
Joe Fischer
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Some does, and that's easy to do with minimal air leakage.
Nick
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On 21 Sep 2006 13:42:05 -0400, snipped-for-privacy@ece.villanova.edu wrote:

Make up your mind, is it leakage, or powered mandated air exchange. Can the right amount of leakage qualify as a measured amount of air exchange. Is the heat in the air being exchanged all that much, or is most of the heat in the solid objects in the house. Do I really need another fan running to be called an efficient house, does that make it more efficient or greener, cleaner or meaner?
I would like to make a suggestion about all government regulations other than safety and security.
Joe Fischer
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You might enjoy figuring that out :-)

Not on a mild day.

Not at all, with an exhaust fan.

Only your hairdresser knows for sure.
Nick
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wrote:

You really are 'reading' Nick the wrong way.
Yes, warming outside air as it enters a house lowers its RH (doesn't change its dewpoint or specific humidity though). Yes, most people are more comfortable with RH around 50%, and many household items such as wood furniture are less likely to shrink/crack if the humidity is maintained.
Nick is *only* saying that you don't need to add a lot of moisture to the air *if* you don't have a lot of air exchange. If air exchange is kept down to a minimum, then the amount of moisture you have to add is also a minimum. Experts/standards tell us that you *don't* need a whole-house air change every 2 or 3 hours. *That* level of air exchange does require you to add a lot of moisture. And that takes a lot of energy.
Reducing the air exchange rate to something a lot closer to the 'standards' level will greatly reduce the amount of moisture that needs to be constantly added to a house. Nick *has* said that with the minimum air exchange, the moisture given off by people and activities will accumulate enough to raise the humidity into the 'comfort zone'. But I think that would only be true in mild winter climates such as his (Philidelphia).
Nick also maintains that the old wive's tail that humidifying your house saves energy is bunk. It may feel more comfortable, but it takes more energy to maintain that humidity level than it does to just maintain the air temperature. Lowering the exchange rate will save energy in two ways, a) it lowers the amount of heat lost with the outgoing air, and b) it lowers the amount of energy needed to maintain comfortable humidity levels.
daestrom
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snipped-for-privacy@ece.villanova.edu wrote:

Airitght houses are very unhealthy.
Graham
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On Thu, 21 Sep 2006 00:39:18 +0100, in misc.consumers.frugal-living Eeyore

I know someone who has a house that is so airtight that it came with an air exchanger. Crazy..
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snipped-for-privacy@aol.com wrote:

I know someone who has a house that is so drafty they spend huge amounts of money on heating and cooling. Crazy...
Anthony
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An exhaust fan with a 60% humidistat is cheaper. Latent heat may be worth exchanging. Even air-leaky houses need ventilation on mild days...
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Canada says all new houses there should be equipped with an air to air heat exchanger that ventilate the house several times a day (I forget the actual spec)
If the outside air temp is -20F, you want to introduce as little of that as possible to the house. Air to air heat exchangers will raise that incoming temp quite a bit by cooling off the outgoing air.
Nope not as cheapas Nick's solution, but our Northern neighbors have much more severe winters than most of us in the USA experience.
Even Washington state mandates a ventilation system in all new residential construction (they don't say what it has to be just that there is one)
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Do let us know when you find this alleged spec. Meanwhilst, you might explain the new houses in Ontario with exhaust fans vs ERVs.

Sounds like an exhaust fan would qualify there as well.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

http://r2000.chba.ca/What_is_R2000/R2000_standard.php
YOU pointed the spec to us, NOW READ THIS PAGE
Note that this is not a MANDATORY construction method, it is a voluntary program designed to influence both builders and consumers.
R-2000 homes will be blower door tested to ensure that the required standard for air tightness is met.
Mechanical ventilation systems must be provided. Most R-2000 builders use a Heat Recovery Ventilator
Note that not all R-2000 homes are REQUIRED to have HRVs, they point out that builders who follow the spec to produce an R-2000 certified home will often choose to include an HRV as the chosen ventilation method.
And Canada is far more than just Ontario, and Ontario is far more than the southeastern region that lies just across the lake. Toronto winters are very different than Chicoutimi, or Calgary, or even locations in Ontario in the north and west regions. R-2000 addresses the needs of the ENTIRE country.
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Do "they" also say that all new houses "should" be painted white? :-)
http://r2000.chba.ca/What_is_R2000/R2000_standard.php

No thanks.

Aha. That kind of "should," as in "All men should be named Dave."

From the mountains, to the prairies, to the oceans, white with foam...
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Now it was Nick who pointed out that IDEA 2000homes in Canada leak at 2.5CFM vs 200CFM for good US houses, and now he won't even read the pages from whence these figures were quoted!!!!!!
Aha should back at you, as if my house can be adequately conditioned (Heated and cooled) by burying 500 feet of 6 inch diameter pipe 6 feet below the surface and blow 300 CFM thru the pipe. In SOME parts of the US that will work in combination with solar heat management, great insulation.... Temperature to cool climates yes, however I do not live in a temperate climate. AC runs a few hours EVERY SINGLE MONTH OF THE YEAR.
It just won't work. One size does not fit all!!!
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On 21 Sep 2006 13:39:03 -0400, in misc.consumers.frugal-living snipped-for-privacy@ece.villanova.edu wrote:

Leaving the door open is more frugal. It's not that cold here unless you're in Eastern Washington.
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snipped-for-privacy@ece.villanova.edu wrote:

Building code requires a "balanced ventilation system". What exactly that means is highly dependent on the building inspector you get. _Many_ inspectors take that to mean an HRV.

My friend who builds passive-solar homes has argued this for years. Given that he's a qualified engineer AND architect, he knows what he's talking about, but he still has trouble with some inspectors.
--
derek

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Au contraire, current thinking is "build it tight, and ventilate it right."
Some Canadian houses are extremely airitght, and very healthy.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Yes, very airtight, with controlled, heat exchanged ventilation HRV, with ERVs recommended.
Get them very tight to minimize heat gain/loss as appropriate, and introduce outside air at controlled rates with minimal loss of heated (or cooled) air.
Energy savings of 30-40% are documented in Canada
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HRVs are not required by law in every part of Canada. Some of those airtight houses just have exhaust fans, eg R2000 houses in Ontario. Exhaust fans waste more energy than HRVs and ERVs, but the amount of energy isn't large, and it may not matter in a solar-heated house :-)
OTOH, the legal requirement for HRVs on Minnesota's air-leaky houses seems to be a successful lobbying effort and a serious waste of money.
Nick
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On Tue, 19 Sep snipped-for-privacy@aol.com wrote:

Sorry for not removing the crossposting.
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.
Joe Fischer
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