HVAC question - Page 4

Posted by Stormin Mormon on October 19, 2009, 7:58 am

Makes me wonder if the installers added a humidifier. If so,
it may be set too high. Please call whoever installed the
furnace, they are likely to know the details.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

Hello,

I have a 2600 sq ft 4 level split home in Canada. It
was built in
1985. This past spring we replaced our very non-effecient
furnace with a
Tempstar 95% effecient gas furnace. It really is wonderful
as the old
furnace would cause the house to feel sort of drafty and
basement was always
cold etc... Now I have this furnace that I love to bits BUT
now since it has
gotten colder outside these past two weeks, we have kept the
doors and
windows closed and now have a high humidity problem inside
the home IE:
fogged up windows (triple pane)...air basically feels
clammy...bought a
humidistat and the house is sitting at around 50%
humidity.... we use
bathroom fans in the shower, and have a fan over the stove
when cooking that
we use all the time...we keep lids on pots on the stove
etc...We have no
children and only the two of us in this home so no long
lingering showers by
kids or anyone else....
I don't want to have to buy a dehumidifier over this
new furnace..
sort of defeats the idea of trying to be energy effecient...
Thinking of
trying to duct in an outside air source to feed the furnace?
Thoughts? Thanks... Jim

Posted by Jim Elbrecht on October 19, 2009, 8:16 am

>Hello,
> I have a 2600 sq ft 4 level split home in Canada. It was built in
>1985. This past spring we replaced our very non-effecient furnace with a
>Tempstar 95% effecient gas furnace. It really is wonderful as the old
>furnace would cause the house to feel sort of drafty and basement was always
>cold etc... Now I have this furnace that I love to bits BUT now since it has
>gotten colder outside these past two weeks, we have kept the doors and
>windows closed and now have a high humidity problem inside the home IE:
>fogged up windows (triple pane)...air basically feels clammy...bought a
>humidistat and the house is sitting at around 50% humidity....

What did you change in addition to the furnace? Windows? insulation?
Did the furnace come with a humidifier?

The last would be my guess-- and it should have both an adjustment and
an outside sensor.

What does the installer say?

Jim

Posted by on October 19, 2009, 8:47 am

> >Hello,
> > =A0 =A0 =A0 =A0I have a 2600 sq ft 4 level split home in Canada. It was=

built in

> >1985. This past spring we replaced our very non-effecient furnace with a
> >Tempstar 95% effecient gas furnace. It really is wonderful as the old
> >furnace would cause the house to feel sort of drafty and basement was al=

ways

> >cold etc... Now I have this furnace that I love to bits BUT now since it=

has

> >gotten colder outside these past two weeks, we have kept the doors and
> >windows closed and now have a high humidity problem inside the home IE:
> >fogged up windows (triple pane)...air basically feels clammy...bought a
> >humidistat and the house is sitting at around 50% humidity....

> What did you change in addition to the furnace? =A0Windows? =A0insulation=

> Did the furnace come with a humidifier?
> The last would be my guess-- and it should have both an adjustment and
> an outside sensor.
> What does the installer say?
> Jim

It's possible the new furnace has a seperate intake where it pulls
outside air in for combustion. The old one drew air directly from
outside, so there was always a significant amount of fresh air being
pulled into the house, at least into the basement. That would have
lowered the humidity, but now that is gone.

I agree with others who have said 50% humidity isn't excessively high
and it shouldn't make it feel clammy. It is the highest you would
want it though, otherwise you risk condensation. You wouldn't want
it that high when it's 15 outside, but by then with the furnace
running more, it's likely the humidity will decrease.

Posted by bud-- on October 19, 2009, 10:30 am

trader4@optonline.net wrote:

>>> Hello,
>>> I have a 2600 sq ft 4 level split home in Canada. It was built in
>>> 1985. This past spring we replaced our very non-effecient furnace with a
>>> Tempstar 95% effecient gas furnace. It really is wonderful as the old
>>> furnace would cause the house to feel sort of drafty and basement was always
>>> cold etc... Now I have this furnace that I love to bits BUT now since it has
>>> gotten colder outside these past two weeks, we have kept the doors and
>>> windows closed and now have a high humidity problem inside the home IE:
>>> fogged up windows (triple pane)...air basically feels clammy...bought a
>>> humidistat and the house is sitting at around 50% humidity....

>> What did you change in addition to the furnace? Windows? insulation?
>> Did the furnace come with a humidifier?
>> The last would be my guess-- and it should have both an adjustment and
>> an outside sensor.
>> What does the installer say?
>> Jim

>
> It's possible the new furnace has a seperate intake where it pulls
> outside air in for combustion. The old one drew air directly from
> outside, so there was always a significant amount of fresh air being
> pulled into the house, at least into the basement. That would have
> lowered the humidity, but now that is gone.
>
> I agree with others who have said 50% humidity isn't excessively high
> and it shouldn't make it feel clammy. It is the highest you would
> want it though, otherwise you risk condensation. You wouldn't want
> it that high when it's 15 outside, but by then with the furnace
> running more, it's likely the humidity will decrease.

Sounds like an entirely reasonable answer.

And as the outside temperature drops the moisture content of the outside
air also drops, which should lower the inside humidity.

I don't remember it has come up, if the furnace combustion is
discharging into the house the humidity would be high. The probability
is very low for a new install, but possible. A carbon monoxide detector
is a good thing to use in any case.

--
bud--

Posted by Jules on October 19, 2009, 1:31 pm

On Mon, 19 Oct 2009 05:47:04 -0700, trader4 wrote:

>> >Hello,
>> > I have a 2600 sq ft 4 level split home in Canada. It was built in
>> >1985. This past spring we replaced our very non-effecient furnace with a
>> >Tempstar 95% effecient gas furnace. It really is wonderful as the old
>> >furnace would cause the house to feel sort of drafty and basement was always
>> >cold etc... Now I have this furnace that I love to bits BUT now since it has
>> >gotten colder outside these past two weeks, we have kept the doors and
>> >windows closed and now have a high humidity problem inside the home IE:
>> >fogged up windows (triple pane)...air basically feels clammy...bought a
>> >humidistat and the house is sitting at around 50% humidity....

>
> It's possible the new furnace has a seperate intake where it pulls
> outside air in for combustion.

Hmm. Ours has an intake and outlet to the outside world - but it also has
a small shoebox-sized pump beside it, which collects moisture and pumps
it into the waste water system for the house. I'm not sure if that pump
is for extracting moisture that's in the air, or from the gas supply -
but given the way it's floor mounted beside the furnace it looks like
optional extra equipment, as otherwise surely it'd be built into the
furnace...

If it *is* optional on furnaces and the OP doesn't have it, maybe they
need it, whatever its exact function is...

(just idle speculation, not based on any knowledge of how furnaces work! :-)

cheers

Jules

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