Condensation on Windows – Is it Bad?


It's that time of year when condensation on windows becomes a hurting, we wake upwards in the morning, tin't come across out, curtains are wet, at that place's water on the window bottoms, and even worse it can affect the walls below windows causing mold and mildew in drywall and furniture.

Condensation is bad news in multiple ways – information technology indicates where a home has weak spots or thermal bridges in its insulated envelope, it points to problems in high humidity levels in the home – possibly coming from subconscious bug in basements, crawlspaces, walls or ventilation systems – and some things are certain when a home has condensation running downwardly the windows:

  • Condensation won't disappear on its own
  • Condensation is potentially detrimental to health as it allows for mold and mildew growth
  • Condensation can cause impairment to homes and lead to costly renovations and repairs

So, the question is – what should we do well-nigh condensation? How do we fix and forbid condensation in our homes?

Condensation in homes – the basics


And then what is condensation? Condensation in its purest form is caused when humidity in the air comes in contact with a cold surface and it condenses from a gas to a liquid over again.
Where nosotros notice it well-nigh in our homes is on windows, or on the sides of a nice chilled glass of chardonnay or a cold beer – with the exception that one denotes a pain in the butt, the other pleasure!

Condensation on glass - no cause for celebration!
Condensation on glass - no cause for celebration!

The reason we notice condensation nigh on glass is that information technology's an impervious cloth – the water has nowhere to go so it sits there, waiting for united states to wipe it off and running down until information technology does find a surface to soak into – which is unfortunately where the issues starting time to occur. Unless of course it's soaking into our t-shirt on a hot summer'due south day - but nosotros're talking here about the miserable & cold kind that sits on the bottom of windows in wintertime and can fifty-fifty freeze up if we're actually unlucky and the forest stove went out overnight! (Which is what inspired Harold Orr to design the Saskatchewan Conservation Business firm, which in 1977 acted every bit a laboratory for the development of many previously unheard of building techniques that are at present standard on the best performing houses in the world.)

The other factor to consider, other than warming cold surfaces to mitigate condensation which is the traditional route to reducing condensation on windows, is that information technology can also happen when there's simply too much humidity in a domicile. Every bit noticed most often in the colder months of the year when information technology meets the common cold glass of bedroom windows, equally cooling air becomes unable to hold as much moisture, it condenses.

So, at information technology's simplest, condensation on windows is the result of relatively warmer and humid air coming together a cold surface - but this is on a sliding calibration.

To look at this in a scientific style, let's use some information from the Passive Firm Institute. Their recommendation is for surfaces in the home to be a minimum of 55 degrees Fahrenheit (12.6 degrees Centigrade) including the surface temperatures on windows if relative humidity is 50% to prevent a localized window Relative Humidity of greater than eighty% at the glass - which is what causes the condensation on windows or window frames if they are unmarried or double glazed - peculiarly if they take aluminum glazing bars.

What's the problem with condensation?

Traditionally, almost building experts will mention mold and mildew as the main bug caused by condensation in homes – but showtime off, here's a point to think about in connection with condensation on windows that we haven't seen specifically mentioned anywhere.

As a key chemical element of Passive Business firm, Net Zero Energy and high-performance homes is consistently making the most of Passive Solar Proceeds, having a abode where each day starts with fogged over windows is absolutely a huge detriment. A hidden outcome of condensation on house windows is that once the sun does come up up, which could and should be heating our high performance abode'due south interior in the colder months, instead the sun'south heat is being used up to evaporate the window condensation while also putting all that moisture back into the home interior and ultimately raising the humidity level. (About folks don't realize that evaporation is the biggest cause of heat loss in a pond pool likewise).

And then that'southward one issue that makes condensation a problem, using energy unnecessarily – but so of course damp is caused by condensation too and our homes are more often than not not built to resist moisture. Even minor water harm tin can leave severe stains and damage on drywall while other times you will demand to completely remove the damaged drywall and replace it – especially if it becomes badly afflicted past mold and mildew – which usually makes an appearance as a cloud of picayune black dots around windows or in the corners of rooms.

Condensation causes mold and mildew around windows
Condensation causes mold and mildew around windows

Every bit condensation occurs when moist air comes into contact with a colder surface like a wall, window, mirror etc. this is usually where nosotros find mold and mildew growth first – but nosotros've too seen it behind wardrobes and furniture where air doesn't broadcast as freely and then the drywall can't dry out.

Mold can grow on nigh any organic fabric equally long as moisture and oxygen are present. There are molds that grow on:

  • Forest
  • Newspaper
  • Carpet
  • Food
  • Insulation

Because mold eats or digests what information technology is growing on, it tin damage a building and its effects. If left unchecked, mold eventually can cause structural damage to building materials, rotting wood, disintegrating drywall, costing the homeowner money for remedial work and potentially reducing a dwelling's value

If the humidity level in a home is to a higher place 60%, certain molds commencement to abound and flourish in nether 12 hours – so if condensation is nowadays, there's about certainly mold and that may become a big issue..

Condensation, humidity, mold and health

Exposure to clammy and moldy environments may crusade a variety of health furnishings, (or none at all). Put simply, some people are sensitive to molds. For these people, molds can cause nasal stuffiness, pharynx irritation, coughing or wheezing, eye irritation, or, in some cases, peel irritation. People with mold allergies may have more severe reactions and allowed-compromised people and people with chronic lung illnesses, such as obstructive lung illness, may get serious infections in their lungs when they are exposed to mold. These people should stay away from areas that are likely to have mold – such as a domicile with high humidity.

In 2004 the Plant of Medicine (IOM) found at that place was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, coughing, and wheeze in otherwise good for you people; with asthma symptoms in people with asthma; and with hypersensitivity pneumonitis in individuals susceptible to that immune-mediated status. The IOM also plant limited or suggestive show linking indoor mold exposure and respiratory illness in otherwise healthy children.

In improver, also in 2004, the IOM constitute sufficient evidence to link exposure to damp indoor environments in general to upper respiratory tract symptoms, coughing, and wheeze in otherwise good for you people and with asthma symptoms in people with asthma. The IOM likewise plant express or suggestive evidence linking exposure to damp indoor environments in full general to shortness of jiff, to respiratory illness in otherwise healthy children and to potential development of asthma in susceptible individuals. In 2009, the Earth Health System issued additional guidance, the WHO Guidelines for Indoor Air Quality: Dampness and Mold .

Other contempo studies take suggested a potential link of early on mold exposure to development of asthma in some children, specially among children who may exist genetically susceptible to asthma evolution, and that selected interventions that improve housing atmospheric condition can reduce morbidity from asthma and respiratory allergies.

Condensation relative humidity temperature and health problems graph
Condensation, relative humidity, temperature and health problems graph - how they all chronicle

Before we all panic considering we noticed some condensation in our homes, think that eliminating all mold and mold spores indoors is virtually impossible, merely controlling indoor moisture and humidity levels will control the growth of indoor mold – so this is the primal.

Condensation is a symptom of other problems

Consider condensation every bit a symptom and not a cause of home humidity being too high, and then, if in that location'south condensation happening on windows, the showtime step we'd suggest is to get concur of a hygrometer or humidity meter or monitor to test the level of relative humidity in the home – because ironically the higher performance the abode gets, with air barriers and better windows and doors, the more chance at that place's going to be a problem with humidity unless it'due south been designed with automatic mechanical ventilation systems like HRV'due south & ERV's from the off (Which many haven't).

The original hygrometer was called a sling psychrometer – and consists of 2 thermometers mounted together with a handle attached on a concatenation. Ane thermometer is ordinary, the other has a cloth wick over its bulb and is called a wet-seedling thermometer.

But this is the electronic age – so if money is no object, at that place are smart hygrometers available that monitor year-round and have maximum and minimum alarms. One of the meliorate ones nosotros institute is the Temp Stick at around $150 which comes with a 5-year warranty and is Made in USA! If on more of a budget, we've had good experience with the ThermoPro TP50 digital hygrometer – inexpensive as borscht, pretty authentic, and does the task for around $10.

Monitor humidity levels in the home over a week and at different times of the day and we're willing to bet that they get in a higher place sixty% relative humidity. If so, then in that location are several things to do that will assist:

  • Limit the amount of humidity beingness produced in the home or entering it.
  • Ventilate the abode to remove excess moisture.
  • Dehumidify the air in the home to bring the relative humidity below the 60%.
  • Estrus and insulate homes evenly to try to foreclose cold spots that volition provoke condensation.

The question remains, how practise we practice all those for the all-time, to help reduce the humidity level and reduce the chance of condensation?

How to reduce condensation in homes?

How should we limit the amount of humidity inside homes & reduce condensation? Once nosotros've identified that a home is over the recommended humidity level of lx%, nosotros should firstly try to place where this backlog wet is coming from. All living organisms give off humidity but by existing, humans, animals, even plants – so is the habitation large or small in relation to the number of occupants? This might be the ideal time to turf those 20 something kids out of the house, citing that they are risking devaluing their inheritance and that information technology really is time they got a place they can call their own (and leave us in peace!) – Surprising how rarely Mom'south buy into this every bit a plan!

Interestingly, up to one-half of the loftier humidity solution is changing personal habits in the dwelling:

  • Showering - The bathroom is the about boiling place in the domicile, and something every bit simple as taking a shower releases huge amounts of humidity into the air – the hotter information technology is and the longer it is, the more water vapor is released. So, to reduce this avoidable humidity source and save energy and water, always be sure to shower with a friend, failing that the dog, or otherwise - just try to proceed to a reasonable temperature and timespan – while running the bathroom fan during the shower and for 15-xx minutes after to get that boiling air exterior. Because of the number of incorrectly installed bathroom fans nosotros've seen installed – it'due south also probably worth double checking in the loft space that bathroom fans are correctly vented to outside and that joints are duct taped up properly too – because venting into the roof void but creates condensation, mold and forest rot problems up there instead of in the habitation itself. Make sure too to utilise a decent size bathmat to avoid saturating bathroom floors when getting a bath or shower. The bathmat should help soak up some of the moisture, helping to reduce the condensation in the room, especially if it is put in the dryer along with the wettest towels.
  • Cooking and using a kettle or coffee maker – Kitchens are the 2nd biggest source of home humidity, cooking, kettles and appliances all release steam, so be sure to use pan-lids when cooking to reduce moisture existence created from the water boiling, to speed up the fourth dimension it takes to rut pans, and accept a cooker hood that's fix to excerpt and use it all the while cooking and for a little time afterward. Over again, much every bit with bathroom fans, check ductwork for taped and sealed joins – and when ownership a new cooker hood, buy a quiet one by preference and and so it'southward more likely to get used.
  • Shut kitchen & bathroom doors – As bathrooms and kitchens are the worst culprits for condensation. when cooking nutrient, humid the kettle or taking a shower, ensure that the kitchen or bathroom door is kept closed to prevent the moisture in the air from going into colder rooms which will cause condensation to class if it touches a common cold surface.
  • Laundry – Never, always, EVER dry out laundry inside on a rack or line when it's common cold outside – every load releases most 5 pints of h2o into the air. If it won't dry out outside, so don't attempt to dry out it inside unless in an exterior-vented dryer. The second reward is for interior air quality – as the bogus scents in laundry detergents and softeners will mostly misemploy outside so we aren't breathing them in. Once more, double cheque ducting for leaks.
  • Unvented gas heaters, stovetops & ovens – When natural gas or propane and butane burns it releases water vapor and potentially carbon monoxide. None of these are good in homes or our lungs or bloodstreams, so either choose a different heat source where possible, like a overnice forest called-for stove, or if non then ventilate to get that all outside.
  • Humid basements or crawlspaces – When a home is built on a crawlspace or basement this can oftentimes be the cause of humidity in the dwelling – even when the home is newer many areas building Lawmaking'south lock humidity in finished basement walls for years, causing clammy and mold bug. Many basements were built with inadequate insulation, see here to find out how to improve it if so, or see here for more information on insulating crawlspaces. To larn how to prevent mold in basements, run into here – or how to forestall humidity and radon gas in crawlspaces run across here. To learn how to build a home on a slab-on-class foundation which is our preferred selection, encounter here.
  • Those pre-Christmas home renovations – People often want to freshen upwards their homes in preparation for the holiday season, but if painting large areas of wall so all that has to dry, and this moisture goes straight into the interior air unless the space is well ventilated. Be sure to choose zero VOC paints, or it's fifty-fifty like shooting fish in a barrel to brand VOC complimentary pigment, observe out how here, and choose nice conditions for internal painting so the windows can exist flung wide open to go those chemicals and that water vapor ventilated outside.
  • Modern air workout systems - Believe it or not, AC systems can enhance the levels of the humidity in homes. Specifically, I mean the newer models that are supposedly going to save upwardly to 50% in electric bills because they work faster and use less energy. The part about spending less free energy because they are faster and cool down the habitation faster is true. Nevertheless, the older AC models, which had to run longer to attain the desired temperature, were often improve at removing humidity from the air just because they were running longer. On the other paw, the new models, because they achieve the desired temperature much faster, don't remove the humidity from the air. In that location might even exist more relative humidity than before turning it on as the libation air has less ability to retain moisture vapor. The solution is to make sure that whatsoever "winter" mode is actually acting as a dehumidifier and that the relative humidity measures less if the unit of measurement is running in winter manner – we've had a few surprises!
  • Careful choice of houseplants - If living in an area where the natural humidity is already high, having plants such as Ginger, Asplundia, Monstera, Ficus Benjamin, Areca palm, and Bamboo palm will but make humidity bug worse – choosing plants like Peace Lily, Boston Fern, Orchids, Spider Plant, Tillandsia,  Cactus and English Ivy should help lower humidity and ameliorate internal air quality, merely h2o sparingly and often for best effect.
  • Bank check for water leaks! – Any pipes carrying water in the house, both delivery of hot and common cold or heating and evacuation, should exist checked for leaks and any leaks stock-still promptly. All backlog humidity in a home's construction is best removed at the source – and so likewise check gutters, downspouts, roof coverings and rainscreening for signs of leaks.
  • Cull & fit loftier efficiency HRV or ERV units – With modern homes being more than airtight, it's also a great thought to fit a mechanical ventilation organization with estrus or energy recovery depending on the climate zone the property is in. To acquire more about mechanical ventilation systems, encounter here – or to discover how to choose between an HRV or ERV unit, see here. If in a common cold climate, it's also a great idea to fit a low level evacuation pipe on the HRV or ERV unit rather than a roof vent that can freeze up and be difficult to check and keep clear.
  • Fit a high efficiency and appropriately sized dehumidifier – Once everything has been checked and sources of humidity in the home reduced as much every bit possible – if the relative humidity levels stay too high then at that place is always the possibility of running a dehumidifier or multiple dehumidifiers for each level of the dwelling house to bring the humidity levels down into the ideal range to avert condensation, mold and mildew.

Other ideas to minimize condensation in homes

A key condensation signal is windows, and the best fashion to go along on top of condensation around windows is to be on the lookout for any harm to the sealant around the window frame equally this tin can allow water in – to learn how to fit and seal windows properly, see here.

Likewise, if there is some condensation, try to wipe down windows and window sills promptly with a sponge that gets wrung out down the drain and rinsed in bleach, to ensure no excess moisture enters the property's air and open windows as ofttimes as possible on warmer days to allow air to circulate.

As rooms like bathrooms are optimum environments for high humidity causing condensation, getting into the habit of using a silicone squeegee on shower enclosures and tile after finishing a shower encourages h2o to drain away rather than it take to evaporate.

Condensation on unused bedchamber windows may be noticed concluding, especially as it is a room not used very oft. Signs to look out for with condensation around chamber windows are; water on the windowsill, impairment to window frames and it is likewise of import that you don't ignore black mold on soft furnishings like curtains or cushions – we would always propose keeping the heat turned up in the spare rooms of a firm – it'due south by and large a false economic system turning off the rut every bit they become a magnet for clammy, mold and insect attack.

I've just realized, the condensation is between the glazing panels!

Condensation within double glazing typically suggests that there is a problem with the sealed unit in the windows. This means that a signal in the edge seal of the window has failed and is allowing moisture to enter considering the sealant between the glass and frame volition have to be renewed. For help on deciding when to alter windows, see here - or for help in deciding which type of windows to choose, meet here.

On older or poorer quality units, the sealant used to create the seal (effectually the windows) may be of a low grade or get loose over time. If the seal and bead that's supposed to agree the glass in the frame deteriorates, moisture and water tin can get into the frame. Assuasive big amounts of water to settle in a window frame similar this for a long period of time volition somewhen touch on the 'air gap' seal surrounding the 2 panes of glass and if it's a wooden frame it volition cause it to rot.

Condensation in double glazing sealed units is expensive to repair
Condensation in double glazing sealed units is expensive to repair

Sometimes, uPVC frames will crack and allow h2o to gather. Another reason why you may see condensation in double glazing is because of a fault with the 'spacer' bar. Most double-glazed windows now feature a 'spacer' in betwixt the ii panes of glass and this is full of desiccant, a highly-absorptive material which sucks up any moisture in the 'air gap' void. In fact, you're as likely to get condensation on new windows as old windows, and new windows may even increase condensation, since they should reduce draughts in the dwelling. That said, condensation on the inside of windows is something we should try to reduce, since it can damage window frames.

If there is even the slightest imperfection in the seal, this desiccant can quickly become saturated by any moist air or water which enters. When it cannot retain any more than, the moisture then begins to appear every bit condensation between the panes of a multi pane window, most ofttimes noticed on a sunny day when it looks foggy.

If you have condensation in double-glazing, then it is a sign that the sealant has failed, and this normally means that it volition have to be replaced or resealed. If the windows are old, then replacing the whole unit can be recommended so that the aforementioned trouble does not occur again.

What other types of condensation can happen in homes?

Interstitial condensation creates structural damping and subsequent damage that occurs when moist air penetrates inside the hidden space within an enclosed wall, roof or flooring cavity of a home. When that moisture laden air reaches a layer inside the interstitial structure (or simply put, wall or roof cavity), that is at dew betoken temperature, it volition condense into liquid h2o which and so soaks into timber, insulation and drywall. This is often a problem with flat and cathedral roofs but it also happens frequently in framed walls but doesn't get spotted until it'due south too late because of the ubiquitous poly vapor barrier between the drywall and the studs.

The wet laden air can penetrate into hidden interstitial wall cavity from the exterior in warm outdoor temperatures and inside the building during common cold outdoor temperatures.  The resulting structural damage, along with mold and leaner growth may occur without any visible surface indications until significant damage or extensive mold and leaner growth has occurred. To find out more most the difference between air and vapor barriers, encounter here.

This is why it's so very important to carefully seal air-barriers in homes, paying special attention to joins and breaks in the membranes – especially where secondary trades have passed after air-barriers were fitted  - and by using specialist sealing tape that stays stuck downward properly.

Last but not least – if you live in a cold climate expanse that is susceptible to condensation in homes and are choosing toilets for a dwelling house structure or renovation, past preference specify low menses toilets designed with an insulated h2o tank to avert water damage or mold below the cistern caused by condensation and it sweating down the wall.