Re: Energy efficiency can lead to window condensation

[Guest guest]

My father-in -law had a serious problem with sweating windows and mold for a

number of years. After I looked through his house I realized he stores his

wood for his wood stove indoors in the basement. THIS IS A BIG NO-NO. Do not

store firewood indoors! The following year he stored his wood in an outside

shelter that my hubby and I built for him and the sweating window problem

disappeared.

SW

-- [] Energy efficiency can lead to window condensation

Energy efficiency can lead to window condensation

On the House

& Carey

http://www.theolympian.com/apps/pbcs.dll/article?

AID=/20051224/LIVING04/51224038/1004

During winter months, we receive loads of questions about what

causes windows to " sweat " and what to do about the problem. Beyond

being a nuisance, this condition can lead to mold, rot and a musty

odor throughout a home. Making matters worse, for those in

especially cold climates, the sweat freezes and turns to ice.

This excessive moisture that is commonly referred to as " sweating

windows, " is really condensation — water vapor in the air turning

into liquid water. It's the same condition that occurs when a cold

can of soda is removed from a refrigerator and exposed to room

temperature — beads of moisture collect on the outside surface of

the can to form a layer of condensation.

Many modern energy-efficient windows have features built in to keep

the temperature of the glass as warm as possible and thus reduce

condensation. For example, insulated glass provides superior energy

efficiency to reduce the potential for condensation.

However, there is no such thing as a condensation-free window in

high humidity conditions. Controlling the amount of moisture in your

home is the most effective action you can take to avoid condensation.

Window replacement can do wonders to improve energy efficiency and

increase home comfort, but it might do little to avert sweaty window

syndrome. In fact, just the opposite can be true. Ironically, many

homeowners are discovering that their new energy-efficient windows

have more condensation that their old ones.

While well-insulated, tight-fitting windows provide draft-free

comfort and can help lower your fuel bills, airtight windows can

trap moisture inside your home. Previously, moisture in the air

might have leaked to the outside through openings in your old loose-

fitting windows, thus preventing condensation.

Here are a few ways to dry out sweating windows:

• Open window blinds during the day. This allows sunlight in and

will warm interior air to create natural air currents. The improved

circulation results in more even temperature.

• Use fans in bathrooms, kitchens and laundry rooms to remove excess

moisture in the air. Bathing, cooking and doing laundry are

activities that contribute the most to raising indoor humidity and,

consequently, sweating windows. If you don't have ventilation fans

in each of these spaces, install them. If you do have them, use them.

And it isn't enough just to turn them on while you are performing

the activity — allow them to run for a period afterward to fully

remove excess moisture. The biggest mistake that most folks make is

that they turn the bath fan off just as soon as they finish bathing.

Instead, let the fan run for up to half an hour to fully remove

excess moisture. The same holds true for cooking and doing laundry.

• Use a ceiling fan. Many people believe that a ceiling fan only is

useful to cool you down on those sticky summer evenings. In reality,

a good ceiling fan is like money in the bank year round.

In winter, run the fan in the reverse direction at a low to moderate

speed. The blades will pull air upward toward the ceiling and down

across walls and windows. This air movement will make for more even

heating and will dry most windows of condensation.

• Air out your home frequently by opening doors and windows. Before

there were mechanical vent fans, ceiling fans and dehumidifiers,

opening doors and windows was the only means of improving

ventilation and removing condensation. Despite technology, there is

no replacement for a little free air and the benefits that it can

have on improving indoor air quality.

• Reduce the number of indoor houseplants, as plants increase

humidity levels. If you have a terrarium, you know that the inside

surface of the container is covered with condensation. That's no

accident — plants and damp soil increase humidity. If you have

sweaty windows and lots of houseplants, you might need to thin out

some of the plants indoors to clear the windows.

• Use a dehumidifier to remove excess humidity from the air. A

dehumidifier is essentially an air conditioner that has both hot and

cold coils in the same container. A fan draws humid air over the

cold coil of the air conditioner to condense moisture, which then

drips into a collection container. Dry air passes over the hot coil

to restore it to its original temperature.

For best indoor comfort and health, a relative humidity of about 45

percent is ideal. You can track your home's humidity with an

inexpensive hygrometer.

For more home improvement tips and information, visit the Careys'

Web site at www.onthehouse.com or call 800-737-2474 Saturdays from 6

to 10 a.m.

[Guest guest]

Triple-paned or even just double paned windows almost never see the

kind of condensation that single paned windows do.. Its a simple

fact..

Check out Home Energy magazine's web site.. They don't have an axe to

grind, they are sponsored by the DOE. Lots of good info there on

making your home BOTH energy-efficient AND healthy...

They are a nonprofit.. Not selling any particular product..

[Guest guest]

I'm concerned about the affects of using double pane windows to solve

condensation problems. This is the reason: if house is too humid,

humidity may condensate in walls, where you cannot see it.

I've been working on this problem myself this winter.

I have single pane windows and storms behind them. They were sweating

upstairs only. I put shrink wrap on upstairs windows. Shrink

wrapping some of the windows was helping. However when I got all of

the windows shrink wrapped, the windows downstairs started to sweat,

when they were not before. Therefore, humidity which was trying to

exit the house upstairs but could not, was needing to exit downstairs

instead, so it just redirected problem to new location.

I could have shrink wrapped downstairs windows also. However humidity

would still need to exit, and probably find it's way through poroused

walls or cracks or into attic where I may never notice if it

condensates. It may not condensate I realize but disipate but I would

rather solve the problem by providing an exit point for it so I know.

Once I have the humidity I need in house and provided exit for excess

and windows are not sweating, then I feel I could add insulated

windows for energy conservation, but not to solve sweating problem.

Basically I don't think you cannot maintain 45% humidity safely inside

when weather outside is 20 degrees or lower.

The other part of problem was due to stagnant air between loose

fitting double hungs and tight fitting storms. I read about this in

indoor air quality article about sweating windows. This is when sweat

is on storms but not on double hungs. This was solved by opening

double hung windows so air circulation can get to storm windows. When

indoor air could get to storm windows, it picked moisture up off the

windows within minutes and they stayed dry. Since storms are caulked

in, energy efficiency was okay. Not as great as insulated windows

though I'm sure.

--- In , LiveSimply <quackadillian@g...>

wrote:

>

> Triple-paned or even just double paned windows almost never see the

> kind of condensation that single paned windows do.. Its a simple

> fact..

>

> Check out Home Energy magazine's web site.. They don't have an axe to

> grind, they are sponsored by the DOE. Lots of good info there on

> making your home BOTH energy-efficient AND healthy...

>

> They are a nonprofit.. Not selling any particular product..

>

[Guest guest]

P.S. to my own post. Note: I am not against use of double pane

windows for energy efficiency, but against them as a solution to

window condensation problem. House needs a safe place to exhaust warm

humid air. It USED to be through leaky windows, now where? You have

to plan an exhaust, otherwise no fresh air can come in or warm humid

air finds it's own exhaust path and can cause a hidden condensation

problem. This is what I think based on my current experience.

I'm concerned about the affects of using double pane windows to solve

condensation problems. This is the reason: if house is too humid,

humidity may condensate in walls, where you cannot see it.

[Guest guest]

Warm air can hold much more water than cool air, so the condensation

doesn't 'need' to occur. Mold happens when condensation creates places

where water, 'CFUs' and nutrients are all available simultaneously.

Optimal humidity levels are around 50%. Above 60% or so, you get mold

growth, and below 40% or so, people start to dry out, unpleasantly. If

you have nice snug insulated windows, that eliminates a potential

trouble spot. You also need to have air FLOW. If a house is completely

sealed, not only will humidity go up, you will also encourage all

sorts of problems from things like VOCs offgassing, etc.

Does that make sense?

On 12/25/05, barb1283 <barb1283@...> wrote:

> I'm concerned about the affects of using double pane windows to solve

> condensation problems. This is the reason: if house is too humid,

> humidity may condensate in walls, where you cannot see it.

> I've been working on this problem myself this winter.

> I have single pane windows and storms behind them. They were sweating

> upstairs only. I put shrink wrap on upstairs windows. Shrink

> wrapping some of the windows was helping. However when I got all of

> the windows shrink wrapped, the windows downstairs started to sweat,

> when they were not before. Therefore, humidity which was trying to

> exit the house upstairs but could not, was needing to exit downstairs

> instead, so it just redirected problem to new location.

> I could have shrink wrapped downstairs windows also. However humidity

> would still need to exit, and probably find it's way through poroused

> walls or cracks or into attic where I may never notice if it

> condensates. It may not condensate I realize but disipate but I would

> rather solve the problem by providing an exit point for it so I know.

> Once I have the humidity I need in house and provided exit for excess

> and windows are not sweating, then I feel I could add insulated

> windows for energy conservation, but not to solve sweating problem.

> Basically I don't think you cannot maintain 45% humidity safely inside

> when weather outside is 20 degrees or lower.

> The other part of problem was due to stagnant air between loose

> fitting double hungs and tight fitting storms. I read about this in

> indoor air quality article about sweating windows. This is when sweat

> is on storms but not on double hungs. This was solved by opening

> double hung windows so air circulation can get to storm windows. When

> indoor air could get to storm windows, it picked moisture up off the

> windows within minutes and they stayed dry. Since storms are caulked

> in, energy efficiency was okay. Not as great as insulated windows

> though I'm sure.

>

>

> >

> > Triple-paned or even just double paned windows almost never see the

> > kind of condensation that single paned windows do.. Its a simple

> > fact..

> >

> > Check out Home Energy magazine's web site.. They don't have an axe to

> > grind, they are sponsored by the DOE. Lots of good info there on

> > making your home BOTH energy-efficient AND healthy...

> >

> > They are a nonprofit.. Not selling any particular product..

> >

>

>

>

>

>

>

>

> FAIR USE NOTICE:

>

>

>

[Guest guest]

This makes me think about when I was a kid and nobody had central heat. We lived

in the country and only had a lin stove and no indoor plumbing. (This will

make you acutely aware of where the warm is, or is not!) Seems like everybody

knew you drafted the heat source by cracking the furthest, highest window from

the heater. If you didn't, you'd freeze no matter how much fuel you burned.

The very old wood stoves (especially those imported from Europe - you can find

them in antique stores once in a while) were actually made with these burners on

top of them and some came with matching kettles and pots. The kettles were for

tea. The pots were there because the air would become so dry your skin would

crack if you didn't humidify by putting a pot of water there. Even after we

moved to town and had an oil heater, I recall my mother forgetting to put water

in the pan a couple of times, and that's how she would know. Everyone would get

cracked lips and dry skin as soon as the last of the water had evaporated. Even

in blizzard conditions you had to draft the heat source and humidy or pay the

piper.

When I grew up, I came to the conclusion that the utility monopolies were all

evil, so I got interested in alternative construction, self-generated energy,

and sustainable farming where each product or byproduct feeds the next and you

can make your land support you as close to 100% as possible. We always think

these days in terms of moving and heating or cooling these huge volumes of air,

but the reality is sometimes more like the marshal arts - you merely encourage

something to go where it already wanted to go anyway, and you get a lot of bang

for the buck, so to speak. It's really amazing what can be done with those

little tiny computer fans, if you have a mind to mess with it. (I never knew a

thing about mold at the time, btw. I was just charged up about how much

industrialized energy production and city living screwed around with people's

power to make their own choices about things and how it kept them dependent on

government for every little thing in their lives.)

A few years ago, I was talking to someone from high in the mountains of

Eastern Europe where the government would shut off the heat in the dead of

winter. So the people figured out how to make these super-efficient heating

units out of scrap metal for their apartments. They ran on a little bunch of

wood chips in the burner, and would heat a whole place for a day. It would take

a long time to generate enough heat to do a whole home, so you had to be

thinking in advance and heat defensively - which people in very cold climates do

anyway. But you still had to do the same kind of drafting and humidifying to

make it work for a whole house as you would if you had any other kind of space

heat. I did ask if it wasn't kind of scary to live in a building where many

people had all this homegrown heating equipment and all the fire hazard I

thought it would create. But the guy looked surprised and said, " What? Who's

going to burn down their own house? " And I was thinking, of course, " Well,

millions of city people in America who think heat comes from the gas company,

that's who. " We have such a different mindset here that we miss great ideas like

this heater they invented. They didn't wait for some building inspector's

permission to live, they did it because they couldn't survive otherwise.

[Eventually they dumped their communist government in a most emphatic way

because collectives tend to become mean and incompetent on a large scale - sort

of like giant multinational corporations, no? Which I found particularly

interesting, because my whole reason for investigating such ideas came from the

notion that when people have choices, they will usually act in their own best

interests.]

So - the window problem. I'm thinking the way to solve your problem is

probably something very similar and maybe just as simple as cracking an upstairs

window, except that you have to account somehow for where the vents are sending

the warm air. You might want some of those cheap magnetic vent covers to

redirect the flow where you want it. When you only have a single heat source,

there aren't usually any vents to interfere with managing the flow of heat and

moisture. Used to be, the real point to sealing up windows and doors was not to

keep the warm air from escaping altogether, but to make sure it only escaped

where you wanted it to. That's maybe a little harder when it's already being

moved around with a system of vents, but the general idea would still apply.

Seems goofy, considering all the work you put in, but you might just want to

crack one of those shrink-wrapped windows upstairs.

barb1283 <barb1283@...> wrote:

I'm concerned about the affects of using double pane windows to solve

condensation problems. This is the reason: if house is too humid,

humidity may condensate in walls, where you cannot see it.

I've been working on this problem myself this winter.

Serena

There is no such thing as an anomaly. Recheck your original premise.

...Ayn Rand,

paraphrased

---------------------------------

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[Guest guest]

Yes, this is what I had read. Humidity of 50% desireable for

health, keeping sinuses moist. Dry air can cause dry cracks in

sinuses and in skin, and so they don't act as barriers as well.

This lead me to keeping humidistat on 50% all year in this old

house. In the winter windows sweated but I just ignored it.

Result, window frames are rotting in some windows, so I have to deal

with now. It's in the 20's here now and so humidity over 30% starts

to cause problem with windows.

I wish insulated windows would solve this and I could keep humidity

up since I do have 'itchy' skin and other problems, but I haven't

gotten a cold yet this winter.

I've heard however that warm air and humidity can get into wall and

hit the outside 20 degrees on the 'exterior walls' and condense in

there.

I think you need to have 'positive' air pressure in house, a little

anyway. This keeps cold air leaks from occuring in random

locations. If you have positive air pressure, you need to have a

planned exhaust area. Negative air pressue draws cold air through

tiny cracks in house, pulls air down into house from attic, etc. In

other words, draws air into house from unplanned areas that may not

be very clean.

I'm beginning to wonder if leaky windows are an asset, since you can

see any condensation that is occuring in an obvious location, rather

than hidden problem developing. My house is pretty comfortable

except for itchy skin. However perhaps if I drank more water and

moisturized my skin that would solve.

I don't really know though. Still stumped by this subject of

providing correct humidity for health of house and health of

inhabitants. It seems like a tricky thing so far.

>

> Warm air can hold much more water than cool air, so the

condensation

> doesn't 'need' to occur. Mold happens when condensation creates

places

> where water, 'CFUs'

[Guest guest]

Serena,

I've actually done that in bedroom I sleep in since I want the air

to be freshest there, well oxygenated. I've always felt the need

for fresh air in bedroom when I sleep, so it works out. Windows in

there never fog up so air movement is keeping them clear of

condensation. Humidity in house is 30%. There is no vent in

bathroom and I thought I would have trouble when taking shower or

bath with bathroom windows so I shrink wrapped those and that

worked. Rest of windows upstairs don't fog up after shower either

so air circulation and keeping humidity at 30% seems to be working

for my old house. It looks kind of crazy from the outside when I

approach in my car, as all upstairs windows look like they are open

(well they are open), and the storms that are closed aren't

noticeable so upstairs looks like it's a hot summer's day here, or

I'm some sort of cold air freak!! Anyway air is comfortable in

house. It stays at 71 with 30% humidity and there is no

uncomfortable drafty feeling.

I still seem to crave more fresh air and have to throw the front

door open now and then.

My utility bill for period up to Dec 5th was 214 for gas and 100 for

electricity so 314.00. I'll have to see what next one looks like.

I thought the fresh air intakes I put in would really drive my

utility bill up but I haven't found that to be the case.

I think the positive air pressure in house seem to solve

the 'drafty' feeling house used to have which used to make me feel

cold no matter how warm house was. So, I think the fresh air

intakes have actually helped the house to feel warm and lowered

heating cost but I haven't looked back and made a season to season

comparison.

The only trouble I have is in the summer when intake brings in alot

of humidity. To 'dry out' the house, I turn the air temperature

down much lower than I like it just to 'dry out' the air, then reset

it back up to temperature I like. I think a whole house dehumifier

would solve that problem or just a dehumidifier to dry out air

coming from outside through the air intake.

Funny story about Europeans unfamiliar with problem of 'burning

their houses' down! We Americans can be a bit ditzy in some areas of

living.

>

> This makes me think about when I was a kid and nobody had central

heat. We lived in the country and only had a lin stove and no

indoor plumbing. (This will make you acutely aware of where the warm

is, or is not!) Seems like everybody knew you drafted the heat

source by cracking the furthest, highest window from the heater. If

you didn't, you'd freeze

[Guest guest]

P.S. The way I've determined if I have positive air pressure or

negative is if I open window up a crack and NO AIR COMES IN and in

fact air right at the crack is 'warm', then I figure air is

going 'out' there, so there is positive air pressure in house. If I

open it more and cold air starts to come in, I figure I've opened it

too much, causing air pressure to change to negative and is sucking

cold air in. As long as cracked window is letting air 'out', house is

comfortable. If window is open so much cold air is coming in, of

course, house gets chilly...duh!

Serena,

I've actually done that in bedroom I sleep in since I want the air

to be freshest there, well oxygenated. I've always felt the need

for fresh air in bedroom when I sleep, so it works out. Windows in

there never fog up so air

[Guest guest]

Heh - I was just wondering what would happen if anyone tried to calc the amount

of heat lost by people opening doors to go to Home Depot for stuff to improve

heating efficiency.

2 times X therms for the initial departure and return, plus

4 times X therms for the stuff had to be returned or exhanged until you ended

up with the right stuff, plus

X gallons of gas X 3 for driving there and back 3 times, plus

X dollars for wear and tear on your engine because it totally cooled off while

you were inside Home Depot shopping and caused some metal fatigue and eventual

loss of fuel efficiency to your car engine, plus

50-100 dollars for all the little impulse purchases you made while at Home

Depot and the energy it took to produce and ship them along with all the extra

people who drive in there every day to unpack, stock, sell, and account for all

that stuff you probably wouldn't have bought otherwise, plus

X dollars for all the additional heat loss incurred at their homes by doing

so, plus

X calories you burned installing said stuff and walking and driving around all

over the place (and let's face it - they haven't even figured out how to keep

their own stores comfortable in the winter. Their own ceilings are bare metal,

and they all wear down vests in there.), plus

X extra gallons of gas and jet fuel used by the postal service delivering

payments to the credit card companies for the next 16 years,

times however many millions of people did all that stuff each winter, plus

the cost of paying some additional bureaucrats to create all the stats to tell

you whether it was all a good idea or not, plus

some other bureaucrats to raise and lower interest rates depending on what the

first bureaucrats decided, plus

x times the salaries for a bunch of elected officials to decide whether to tax

you some more at the pump or on your utility bills to offset the revenues lost

through tax credits they gave all the oil companies for being so nice to them

through the years, and the repairs for the mold at the governors' mansions.

Because you can afford it. You now have a theoretical additional $20 dollars in

net spendable income each month, thanks to the energy-efficient stuff you just

installed at the house.

Now, if we could show them how to move money around like that fixing mold

problems, we could all retire insanely wealthy and move into the mold-free

places we built with the proceeds.

Serena

There is no such thing as an anomaly. Recheck your original premise.

...Ayn Rand,

paraphrased

---------------------------------

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