Windows Condensation

bloke91

Hi,

Looking for some advice and thoughts please.

With winter approaching I have been paying attention to and noticed condensation on the inside of my house windows on a couple of days when the temperature dropped. 

Most of the windows in my house are double glazed and all of them replaced around 3 years ago so have good window seals, all bar one that I plan to replace down stairs.

My windows don't have trickle vents fitted  and my house has bathroom extractor fans and insulated attic.

My understanding is condensation on windows is from when cold and warm air meet and allowing sufficient ventilation in my home should mitigate it.  I left the windows open in two up stairs room over night but still noticed condensation on the inside of the windows the following day.

I placed a Thermopro sensor similar to this in the rooms and it indicated a value of above 60% humidity, where as 40 - 60 is the guide and target value.  ThermoPro TP49-2 Digital Room Thermometer Indoor Hygrometer Mini Temperature Monitor Humidity Meter for Home Office Air Comfort Thermo Hygrometer : Amazon.co.uk: Home & Kitchen

Any suggestions on how I could reduce the amount of humidity and keep it at optimal level to prevent condensation build up on the windows? Based on the fact I left the windows open slightly over night and Humidity sensor still showed above 60% with condensation on the windows.  Presumably that suggests small trickle vents wouldn't help?

Thanks in advance for your time.

flashg67

Expensive options are running the heating at a higher heat, and/or fitting a PIV unit, less expensive is a dehumidifier unit. My old house suffers from condensation - it has solid walls - I've found insulated wallpaper on the outside walls has helped too.

MikeJXE

According to extensive google research i did when I had that problem was 

Condensation on the inside of double glazed windows means the windows are working as they should 

Lorian

Get a window vac and smile each time you pour the humidity down the drain using very little energy. Other than that just keep the humidity as low as you can - always use an extractor when cooking on the hob.

FreeBear

MikeJXE said: Condensation on the inside of double glazed windows means the windows are working as they should 

Condensation on the outside indicates a good level of thermal performance. If the inside is getting condensation, it means the inner pane is below the dew point.

Humidity levels here are between 55% and 65% at 20-21°C - Not been cold enough yet for condensation to form inside. But based on previous years, if I maintain a room temperature of 16-17°C, I don't get much moisture condensing on the glass. A little bit on the bottom of the bedroom windows, but nothing to panic over.

ThisIsWeird

bloke91 said:

Hi,
Looking for some advice and thoughts please.
With winter approaching I have been paying attention to and noticed condensation on the inside of my house windows on a couple of days when the temperature dropped.
Most of the windows in my house are double glazed and all of them replaced around 3 years ago so have good window seals, all bar one that I plan to replace down stairs.
My windows don't have trickle vents fitted  and my house has bathroom extractor fans and insulated attic.
My understanding is condensation on windows is from when cold and warm air meet and allowing sufficient ventilation in my home should mitigate it.  I left the windows open in two up stairs room over night but still noticed condensation on the inside of the windows the following day.
I placed a Thermopro sensor similar to this in the rooms and it indicated a value of above 60% humidity, where as 40 - 60 is the guide and target value.  ThermoPro TP49-2 Digital Room Thermometer Indoor Hygrometer Mini Temperature Monitor Humidity Meter for Home Office Air Comfort Thermo Hygrometer : Amazon.co.uk: Home & Kitchen
Any suggestions on how I could reduce the amount of humidity and keep it at optimal level to prevent condensation build up on the windows? Based on the fact I left the windows open slightly over night and Humidity sensor still showed above 60% with condensation on the windows.  Presumably that suggests small trickle vents wouldn't help?
Thanks in advance for your time.

Hi Bloke.

You have recent DG windows, and cond is still forming on the inside. 

You can reduce this in a number of ways, as said above; 

(1) increase the room/house temp in order to keep the moisture in the air rather than it condensing out, but this will obviously increase your fuel bills. And when you do turn down your heating - eg overnight - you will likely find an extra shed-load of moisture ready to cond out big time!

(2) taking greater care to reduce moisture creation. You already use bathroom extractor fans, but do they run for long enough? Do you use an extractor when cooking? Do you dry out clothes indoors?

(3) ventilate the house a bit more. I'm surprised at this; "I left the windows open in two upstairs rooms overnight, but still noticed condensation on the inside of the windows the following day." Which two rooms? I can state with nigh-on 100% certainty, that if you choose two bedrooms, each with similar occupants, and you leave the windows ajar in only one bedroom overnight, the person in the 'ajar' bedroom will wake up colder, but drier :-)

(4) live with it, but get into a routine of mopping it up first thing every morn using a damp cloth, finishing with a dry one.

A house will reduce its humidity by ventilating it more, but it's a balance between doing too much - so being cold - and not enough, so being damp. We all wish to be cosy in the evenings especially, so it's reasonable to bring the temp up a tad and also not have draughts. But bear in mind that these two factors will increase the humidity of the air, and when you turn down/off the heating at night, you can expect much of this to condense out on the colder surfaces such as window panes. So, when you turn down the heating and retire, that's the time to also crack open a couple of windows. You'll wake up to a cool room, but it should be dry. You then close the windows, and turn up the heating to what you require.

Ditto in bedrooms. Keep the heating off until it's needed, say a half-hour before bed. Until then, keep the door closed, and the windows cracked open - you'll have a chilly but dry room. If you want your room cosy before bed, you can shut the windows as you turn on the rad in there, but as soon as you jump into bed, the heating should be off, and the window cracked open again. First thing in the morn, kick whoever out of bed to shut the window and turn on the rad, and bring you a cuppa. You should have a dry bedroom to wake up to. As soon as you vacate the bedroom, rad off, windows cracked open, door closed.

Do as much as you can to reduce the cond like this, but also get into a routine of drying it up each morn so it doesn't cause mould.

FlorayG

I had a terrible problem with this and bought a forced air ventilation unit. It goes in your loft, draws in dry air from outside and forces it into the house, driving out the damp air (created by normal living) through every tiny crack. All my condensation - which was awful when I moved in - completely disappeared overnight and never saw any again. The house is dryer and that means also less expensive to heat

Sarahspangles

bloke91 said:

Any suggestions on how I could reduce the amount of humidity and keep it at optimal level to prevent condensation build up on the windows? Based on the fact I left the windows open slightly over night and Humidity sensor still showed above 60% with condensation on the windows.  Presumably that suggests small trickle vents wouldn't help?

Trickle vents are there to let air in and not really a measure to manage indoor humidity.

We fitted a cooker hood that actually extracts the air rather than recirculating it. We still get some condensation but we use a demumidifier upstairs, rather than whacking on the heating. We have one that clicks to ‘eco’ when the humidity is in range. When I first moved in, it ran on full for weeks (initially round the clock) because the previous owners had a recirculating cooker hood and dried their washing on radiators. The house was saturated.

You can see estimated humidity on the Met Office app. On a rain free day the air is least humid in the afternoon. Today, in sunny Yorkshire, the range is from 85% humidity overnight down to below 60% this afternoon. That’s a good time of day to more fully ventilate the house, though you would as a result be letting out heat in Winter. However outdoor humidity can get pretty low in Winter, I often open the windows for half an hour if there’s a sunny day between Christmas and New Year. With extra cooking and visitors the house seems to need it.

Albermarle

So, when you turn down the heating and retire, that's the time to also crack open a couple of windows. You'll wake up to a cool room, but it should be dry. You then close the windows, and turn up the heating to what you require.

Although leaving downstairs windows open at night is generally not recommended from a security point of view.

We fitted a cooker hood that actually extracts the air rather than recirculating it. We still get some condensation but we use a demumidifier upstairs, rather than whacking on the heating. We have one that clicks to ‘eco’ when the humidity is in range. When I first moved in, it ran on full for weeks (initially round the clock) because the previous owners had a recirculating cooker hood and dried their washing on radiators. The house was saturated.

For some reason I do not fully understand some homes seem more prone generally to condensation than others.
We do everything 'wrong' . Clothes on radiators in colder weather. Family member drying their own clothes in their bedroom. Plenty of baths, showers etc. Extractor fan turned off  in one shower room, and not that good in another one.
Apart from occasionally steamed up windows in bathroom, kitchen just after showers or cooking, there is never any condensation anywhere else. A tiny bit of mould sometimes appears in a bathroom, but that's it.
No dehumidifier, no PIV etc .

Sarahspangles

Albermarle said:

For some reason I do not fully understand some homes seem more prone generally to condensation than others.
We do everything 'wrong' . Clothes on radiators in colder weather. Family member drying their own clothes in their bedroom. Plenty of baths, showers etc. Extractor fan turned off  in one shower room, and not that good in another one.
Apart from occasionally steamed up windows in bathroom, kitchen just after showers or cooking, there is never any condensation anywhere else. A tiny bit of mould sometimes appears in a bathroom, but that's it.
No dehumidifier, no PIV etc .

Some houses are more leaky than others. Throughput of air is good. When people obstruct air bricks, carpet from wall to wall, install double glazing, block off fireplace flues and superinsulate the loft they should expect the house to be like a sauna! It also depends where in the country you live, to be fair.

Albermarle

Sarahspangles said:

Albermarle said:

For some reason I do not fully understand some homes seem more prone generally to condensation than others.
We do everything 'wrong' . Clothes on radiators in colder weather. Family member drying their own clothes in their bedroom. Plenty of baths, showers etc. Extractor fan turned off  in one shower room, and not that good in another one.
Apart from occasionally steamed up windows in bathroom, kitchen just after showers or cooking, there is never any condensation anywhere else. A tiny bit of mould sometimes appears in a bathroom, but that's it.
No dehumidifier, no PIV etc .

Some houses are more leaky than others. Throughput of air is good. When people obstruct air bricks, carpet from wall to wall, install double glazing, block off fireplace flues and superinsulate the loft they should expect the house to be like a sauna! It also depends where in the country you live, to be fair.

We are fully carpeted, double glazed and with a well insulated loft conversion. However we have one open fire and it is an older house with highish ceilings and a big hallway, so I guess it is just that there is more space for air to flow around. Plus we usually have a couple of windows open a little bit unless it is really cold. and there is regular coming and going in the day, with doors opening etc. Guess it is one advantage of having a slightly draughty house !