Humidity Apartment

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Giga - 16 Dec 2005 05:49 GMT

have a couple of (layman's) questions about air humidity in
apartments.

I have recently moved to a new apartment (in a newly built house), and
I have the impression that the humidity in the rooms is way too high.
Each morning, lots of water condenses on the windows (so much water
that it runs down the window panes and drops on the floor). Also,
condensation water drops down from the transom window to the furniture
and floor (it's an attic apartment).

The room temperature usually is between 20 and 23 degrees celsius; the
outdoor night temperatures currently are between -10 and 0 degrees
celsius (if that matters).

My first question is: what can I do to reduce the humidity? Does it
help to turn up the heating? Does wiping the condensation water off
of the window panes reduce the humidity significantly, or is the
amount of condensation water neglectable with respect to the entire
amount of water in the air? Or do I have to ventilate the rooms by
opening all windows for extended periods of time?

Seconds, I'm wondering if a too high room humidity is harmful to
humans. My (tropical) plants seem to like it, but do I have to worry
about my health? I have heard that it can be harmful to the health
if the humidity is too low for longer periods, but what about an
increased humidity?

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00doc - 16 Dec 2005 13:53 GMT

> I have recently moved to a new apartment (in a newly built house), and
> I have the impression that the humidity in the rooms is way too high.
> Each morning, lots of water condenses on the windows (so much water
> that it runs down the window panes and drops on the floor). Also,
> condensation water drops down from the transom window to the furniture
> and floor (it's an attic apartment).

That sounds pretty humid. Is it very small? Or where else would the humidity
be comming from.

> The room temperature usually is between 20 and 23 degrees celsius; the
> outdoor night temperatures currently are between -10 and 0 degrees
> celsius (if that matters).

That's 68-73F for the metric impaired.

> My first question is: what can I do to reduce the humidity?

Get a dehumidifier or find out where it is comming from and correct that.

> Does it
> help to turn up the heating?

Probably not.

> Does wiping the condensation water off
> of the window panes reduce the humidity significantly, or is the
> amount of condensation water neglectable with respect to the entire
> amount of water in the air?

It won't help. What is on the window is very little compared to what is in
the air.

I run two dehumidifiers in my basement during the summer. It is not uncommon
for them to take a gallon or two out of the air every day when it is warm
and wet outside. When the temps get down to freezing I usually can turn them
off.

> Or do I have to ventilate the rooms by
> opening all windows for extended periods of time?

That will help if it is much less humid outside (which is probably is if the
temps are getting down to freezing). The problem is that if the air in
general is not humid then that means that the humdity is comming from
somewhere inside the house. If the apartment is very small it may just be
comming from you.

> Seconds, I'm wondering if a too high room humidity is harmful to
> humans. My (tropical) plants seem to like it, but do I have to worry
> about my health? I have heard that it can be harmful to the health
> if the humidity is too low for longer periods, but what about an
> increased humidity?

It is not directly harmful. If it leads to a mold problem and you are
allergic to the mold then it might be a problem.

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00doc

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Lou Pecora - 16 Dec 2005 14:49 GMT

> > I have recently moved to a new apartment (in a newly built house), and
> > I have the impression that the humidity in the rooms is way too high.
> > Each morning, lots of water condenses on the windows (so much water
> > that it runs down the window panes and drops on the floor). Also,
> > condensation water drops down from the transom window to the furniture
> > and floor (it's an attic apartment).

> > Does it
> > help to turn up the heating?
>
> Probably not.

Well, it might. Warm air can hold more humidity than dry air, but this
sounds more complicated. Is the heating system forced air? Radiator?
Other? Does the heating system have a humidifier? That might defeat a
lot of 'fixes' to your problem. Are the windows double-paned or do you
have storm windows? If they're single pane then a temperature drop
across the pane of 20 or 30 degrees C will often guarantee condensation
on the windows in any situation. That's a big temperature gradient. If
your inside air had the moisture content of outside air, you would see
no condensation, but that inside air would be REALLY dry.

Another possibility (if the system is forced air) is that there is a
moisture source in the ducts beyond a humidifier. I looked at a house
for sale with just this problem. We (luckily) looked at it in the
winter and the moisture on the windows was tremendous. We found that
the ducts ran underground and had corroded away in many places leaving
moist earth to pump water into the heating system. We couldn't buy that
place for obvious reasons.

I guess the bottom line is there are a lot of possibilities that you
will have to track down including the possibility that your humidity is
fine, but the windows are single paned and cold causing normal
condensation.

-- Lou Pecora (my views are my own) REMOVE THIS to email me.

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00doc - 16 Dec 2005 16:10 GMT

>> > Does it
>> > help to turn up the heating?
>>
>> Probably not.
>
> Well, it might. Warm air can hold more humidity than dry air,

Absolutely.

75F will hold much more water than 25F. However, within the range that she
would probably be willing to heat her apartment it probably would not make
much difference. If anything, heating the apartment would increase the
humidity.

> If they're single pane then a temperature drop
> across the pane of 20 or 30 degrees C will often guarantee condensation
> on the windows in any situation. That's a big temperature gradient.

Agreed. I was assuming the apartment also felt humid. Maybe that was not a
safe assumption.

<rest of good information snipped - not that I disagree or find it not
valuable - just no sense in repeating it.>

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00doc

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Mike Dobony - 19 Dec 2005 12:18 GMT

> > > I have recently moved to a new apartment (in a newly built house), and
> > > I have the impression that the humidity in the rooms is way too high.
[quoted text clipped - 17 lines]
> your inside air had the moisture content of outside air, you would see
> no condensation, but that inside air would be REALLY dry.

It makes no difference if the inside air has the same moisture content as
the outside air. The only factors are moisture content and temperature. If
the windw panes are colder than the dew point then you will have
condensation no matter what the outside moisture content is. Theinside air
does not talk tohte outside air to see if it is ready to condense.

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Lou Pecora - 20 Dec 2005 14:37 GMT

> > Well, it might. Warm air can hold more humidity than dry air, but this
> > sounds more complicated. Is the heating system forced air? Radiator?
[quoted text clipped - 8 lines]
> It makes no difference if the inside air has the same moisture content as
> the outside air. The only factors are moisture content and temperature.

Correct. The point was that if the inside air had the same moisture
content as the outside air, then when it cooled by the window pane there
would be no condensation since the air even at the lower temperature
could hold the moisture. I was not implying that the outside air
affects the inside air.

-- Lou Pecora (my views are my own) REMOVE THIS to email me.

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Giga - 16 Dec 2005 17:06 GMT

Thanks for replies. I don't have a humidity gage or a dehumidifier. I
will try to buy a gage this weekend.

One more question. Should I open my windows if its snowing outside? The
weather channel says its 95-100% humidity when it snows. Will that
humidity come into my apartment if I open windows?

My Heating system is electric.

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