Condensate on windows

Wayco Wayne

who has a new addition that has been the construction job from hell. Her latest problem has been massive amounts of condensation on the metal frames of her large new modern windows. When it was really cold before Xmas they found large puddles of water on the floor. The space has is very contemporay with large picture windows with metal frames. The windows are supposed to be high efficiency. The installer and his supplier are telling her that she needs more air flow across the windows. That's how I became involved. I've never heard of such an explanation. What if the room was heated with radiators instead of forced air. How would you wash the windows with air then? They are actually recommending installing fans to blow on the windows to get this air flow across the windows. I think they are just hiding the fact the windows were'nt installed properly and probably don't have the correct thermal break between the outside part of the frame and the inside part of the frame. Give me your feedback.

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=255&Step=30">To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"</A>

Mike T., Swampeast MO

If it's new

there is a MASSIVE (in the tons) amount of water that has to leave the space before it reaches equilibrium. Even if the metal windows have a thermal break the metal inside is likely the coldest thing in the space and water condenses there first.

Has she tried leaving a window or two slightly open? Has your weather been cool and damp (as opposed to cold and dry) lately? Our weather has been that way and interior relative humidity is around 55% in January! Don't even have pans of water on rads this year.

Mark Hunt

A blower door test


would reveal quite a bit about the installation of the windows.

It may be that some strategic caulking would take care of this problem.

Mark H

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Dale

If it's a gas job

make sure your flu products are leaving the space. And what is the room on? If it's a crawl space is there a full vapor barrier? I agee with Mike, I would leave a window open and the heat turned way up for a month to dry the place out after construction. The blower door may be needed also to see if the windows aren't perrimiter insulated.

Unknown

Several things to do

I have had this happen on several occasions. The number one thing that helped most was to have extra vents put into the soffits.

It is also a good idea to put a dehumidifier (portable) in for a few months to get rid of the moisture from new construction and its need to dry out.

I would also determine if there was perhaps a previous problem before the new construction. There could be a combustion problem relative to insufficient air changes.
The new National Fuel Gas Code has gone away from the old rule on air and has gone to using an air changes per hour formula. If this area has less than .6 air changes per hour that needs to be addressed. I agree with Mark you should have a pressurization test done to determine proper operation of all the equipment.

Is the new construction over a basement or is it a crawl space? Was a proper moisture barrier installed if it is a crawl space?

Wayco Wayne

Hey guys

The equipment is new. The space has a heat pump. The existing house has a new condensing furnace, 2 pipe. The water heater has a blower on the flu. I don't think it's a combustion problem. Today I scanned with my infrared thermometer. The addition air temp was a 64 degrees. The wall surfaces were 64 degrees. The 2 pane glass was 58 degrees, the metal frames were 52 degrees. Outside temps were about 45 degrees. Inside RH was 51%. No condensate today. When it hapened she had the humidifier turned way up in the old part of the house, and it was way cold outside. She literally had a river on the floor. She turned it down and it has not happened again. How would a blower door test help?? I suggested putting on the humidistat with outdoor temp reset that Aprilaire sells. Any other thought??

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Mike T., Swampeast MO

DON'T RUN THE HUMIDIFIER

this heating season!!!!

Don_2

You have

> The equipment is new. The space has a heat pump.

> The existing house has a new condensing furnace,

> 2 pipe. The water heater has a blower on the flu.

> I don't think it's a combustion problem. Today I

> scanned with my infrared thermometer. The

> addition air temp was a 64 degrees. The wall

> surfaces were 64 degrees. The 2 pane glass was 58

> degrees, the metal frames were 52 degrees.

> Outside temps were about 45 degrees. Inside RH

> was 51%. No condensate today. When it hapened she

> had the humidifier turned way up in the old part

> of the house, and it was way cold outside. She

> literally had a river on the floor. She turned it

> down and it has not happened again. How would a

> blower door test help?? I suggested putting on

> the humidistat with outdoor temp reset that

> Aprilaire sells. Any other thought??

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 255&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_

Don_2

> The equipment is new. The space has a heat pump.

> The existing house has a new condensing furnace,

> 2 pipe. The water heater has a blower on the flu.

> I don't think it's a combustion problem. Today I

> scanned with my infrared thermometer. The

> addition air temp was a 64 degrees. The wall

> surfaces were 64 degrees. The 2 pane glass was 58

> degrees, the metal frames were 52 degrees.

> Outside temps were about 45 degrees. Inside RH

> was 51%. No condensate today. When it hapened she

> had the humidifier turned way up in the old part

> of the house, and it was way cold outside. She

> literally had a river on the floor. She turned it

> down and it has not happened again. How would a

> blower door test help?? I suggested putting on

> the humidistat with outdoor temp reset that

> Aprilaire sells. Any other thought??

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 255&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_

Jack_23

Constant air circ

Try running your blower all the time. I have a chat with a couple other window companies and ask them what causes interior 'sweating" without being to specific.

Mark Hunt

RE: Blower door


Hi Wayne!

I would be looking to find the air infiltration with the blower door.

The window is getting cold enough to condense water and it just might be air leaks around the windows.

Mark H

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Don_2

you have

The right Idea.When ever the drybulb temp is reduce and the
humidity is held constant,you reach your dewpoint. Not much
more you can do for her other then what you have done and what you are now offering.
I went on a call years ago that the walls was sweating and
the wall paper was sliding down the wall,found the skuttle steam humidifider shorted and saturating the air big time.
Then Mr mold came along a few months after that.
That outdoor sensor has been a blessing.

Don_2

Wayne

Here or some rule of thumbs for window type and space humidity values.
Single payne window +_ 10 rh maxium
Double payne window +_ 30% rh maxium
Triple payne window +_ 40% rh Maxium
This is base on 0 degree outside design temp and 72 degree indoor design temp,Also its rule of thumb.

Now if you really need to do the math here the equation
TGlass=Troom-Ria Divide byR glass x t/room -Temp oa.
If the temp is<then the dewpoint of the room condensation occurs.

T = temperature, R-value{Hr.sg.ft.F}
IA=airflim,OA=design outside air temperature,Dp=dewpoint
R inside air flim=0.680,r single payne glass=0.909
R douple payne glass=1.667,Rtriple glass=2.000
The glass rvalue or for average glass construction.