Heating and air conditioning - humidity too low !!!

Author

humidity too low !!!

Mick

2006-03-25, 5:21 pm

SUBJECT: ============================

I am building a large new house(4100 SQ feet with 17' x 24' living room with
cathedral ceiling) and
I am close to the painting stage so its almost finished. There are 2
furnaces(3 tons each),
one for first floor and basement, and the other for the top floor, 2 large
size humidifiers,
air exchanger, etc... (the whole kit)

My HVAC guy assured me I have overkill for the size of the house and proved
it by showing me
calculations and charts. Hot water is hooked up to the humidifiers. The
problem is The
humidity is way too low(don't want my hardwood floors to crack) around 23%
at full capacity
with the house sealed(all doors and windows closed) after several days. Also
the max
temperature for the first floor was only 18c MAX when it was -7c or colder
outside. My HVAC
guy had to exchange one of the furnace blowers for a bigger one. This raised
the temperature
to 20c(which the thermostat is set to) but now its not cold outside anymore
so I'm not even sure
its really ok. this only improved the humidity by 10% so now at max capacity
it does not go higher
than 33% ????

My HVAC guy doubled checked everything and can't figure it out neither can
I??
He says something is eating all the humidity??????

Ralf.
please help!!!

P.S. there is no air return in the basement (don't know if this will help or
not)

Oscar_Lives

2006-03-25, 8:21 pm

~^Johnny^~

2006-03-25, 9:21 pm

On Sat, 25 Mar 2006 23:44:49 GMT, "Oscar_Lives" <nospam@nospam.net>
wrote:

>
>"Mick" <webmaster@webcasinoguide.com> wrote in message
>news:ZphVf.40902$%N6.796955@weber.videotron.net...
>
>
>Set out some pans of water. Simmer one on the stove all day. Run the
>showers with the exhaust fans off.
>
>Spray some water around the house every now and then.
>

More make-up air (infiltration or fresh air intake, makes little
difference) may prove effective, and economical.

It depends on your local climate and weather conditions.

This is assumong the outdoor air has a higher absoulte humidity (not
relative humidity) than the indoor air. Whne to coo moist makeup air
blends with with the warm dry air indoors, inside relative humidity
will increase, withe teh expemse of slightly increased sensible heat
load, but without the relatively huge latent heat load of evaporating
more water...

--
-john
wide-open at throttle dot info

New Directions In Building Services $Australia$

2006-03-26, 5:21 pm

"Mick" <webmaster@webcasinoguide.com> wrote in message
news:ZphVf.40902$%N6.796955@weber.videotron.net...
> SUBJECT: ============================
>
> I am building a large new house(4100 SQ feet with 17' x 24' living room
> with cathedral ceiling) and
> I am close to the painting stage so its almost finished. There are 2
> furnaces(3 tons each),
> one for first floor and basement, and the other for the top floor, 2 large
> size humidifiers,
> air exchanger, etc... (the whole kit)
>
> My HVAC guy assured me I have overkill for the size of the house and
> proved it by showing me
> calculations and charts. Hot water is hooked up to the humidifiers. The
> problem is The
> humidity is way too low(don't want my hardwood floors to crack) around 23%
> at full capacity
> with the house sealed(all doors and windows closed) after several days.
> Also the max
> temperature for the first floor was only 18c MAX when it was -7c or colder
> outside. My HVAC
> guy had to exchange one of the furnace blowers for a bigger one. This
> raised the temperature
> to 20c(which the thermostat is set to) but now its not cold outside
> anymore so I'm not even sure
> its really ok. this only improved the humidity by 10% so now at max
> capacity it does not go higher
> than 33% ????
>
> My HVAC guy doubled checked everything and can't figure it out neither can
> I??
> He says something is eating all the humidity??????
>
> Ralf.
> please help!!!
>
>
> P.S. there is no air return in the basement (don't know if this will help
> or not)

A humidifier produces water vapour
Vapour will always migrate from a higher vapour pressure to a lower vapour
pressure and will go through any porous surface to do so (air, timber,
masonry, gypsum, etc.). If you want your humidifier to work efficiently and
effectively - you must vapour seal using acrylic paints and sealants the
perimeter of that zone.
Once the vapour is of sufficient density in a sealed space, this shall be
stable and the humidifier would shut off (don't forget that the furnace
capacity then reduces by the humidifier energy input) - Until you open a
door or window or introduce another leakage path (note that vapour pressure
is not air pressure and vapour can easily migrate against the flow of air).
It's not the SIZE of your furnace/humidifier - it's how you use it! So if
you don't wish to continue humidifying the Northern Hemisphere and adding
considerably to the greenhouse emissions - check it out and do it right.

Cooltemp Industries

2006-03-26, 6:23 pm

New Directions In Building Services (Australia) wrote:

>(don't forget that the furnace
> capacity then reduces by the humidifier energy input)

Care to expand on that?

~^Johnny^~

2006-03-27, 12:21 am

On Sun, 26 Mar 2006 16:46:09 -0500, Cooltemp Industries
<gbroderick@sunlife.com> wrote:

>Care to expand on that?

It's not in the contract.

--
-john
wide-open at throttle dot info

Murdentech

2006-03-27, 9:21 am

"Mick" <webmaster@webcasinoguide.com> wrote in message
news:ZphVf.40902$%N6.796955@weber.videotron.net...
> SUBJECT: ============================
>
> I am building a large new house(4100 SQ feet with 17' x 24' living room
> with cathedral ceiling) and
> I am close to the painting stage so its almost finished.

Use a good quality primer and good quality latex paint... all that naked
drywall is soaking up the humidity. Don't run the humidifiers continuously
until the painting is complete or you may oversaturate the drywall. A
quality paint job will provide the vapor barrier needed to contain the
humidity in the structure.

>There are 2 furnaces(3 tons each),
> one for first floor and basement, and the other for the top floor, 2 large
> size humidifiers,
> air exchanger, etc... (the whole kit)
>
> My HVAC guy assured me I have overkill for the size of the house and
> proved it by showing me
> calculations and charts. Hot water is hooked up to the humidifiers. The
> problem is The
> humidity is way too low(don't want my hardwood floors to crack) around 23%
> at full capacity
> with the house sealed(all doors and windows closed) after several days.
> Also the max
> temperature for the first floor was only 18c MAX when it was -7c or colder
> outside. My HVAC
> guy had to exchange one of the furnace blowers for a bigger one. This
> raised the temperature
> to 20c(which the thermostat is set to) but now its not cold outside
> anymore so I'm not even sure
> its really ok. this only improved the humidity by 10% so now at max
> capacity it does not go higher
> than 33% ????
>
> My HVAC guy doubled checked everything and can't figure it out neither can
> I??
> He says something is eating all the humidity??????
>

Naked drywall....

Further, most humidifiers are installed to only operate during the call for
heat. If you are turning down the temperature ( or the weather warms up),
the humidifiers are also being turned down, however I wouldn't worry about
this too much until the building is sealed.

> Ralf.
> please help!!!
>
>
> P.S. there is no air return in the basement (don't know if this will help
> or not)
>

It will help control dampness in the basement once the job is finished.

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