To not open windows at home ALL THE EFFING TIME

[R1cciteddy]

My mum is driving me mad with this… she constantly has her windows open at home. No matter the weather. Strangely it’s the kitchen windows she keeps shut. She’s always having a go at me for not opening my windows enough. I’m sick of it I don’t want to freeze. I do sometimes open windows when it’s cold for a bit of ventilation but NOT ALL THE TIME! Yes, my dad pays the bills, not her. Ps my bathroom and kitchen windows are open often. Please help as I’m made to feel like a bad person and that my daughter will have respiratory issues when she’s older due to ventilation. Yes my mother is nuts so they will be open when she visits! AIBU not to open them enough!?

Good I never air my house. I don’t want to let the cold in. Everything is still standing.

Unless you have some other form
if ventilation, you won't get enough to air the house.

The science is surprisingly simple - watch some Peter Ward videos on you tube he explains it well.

Basically moisture laden air is damp and therefore takes longer to heat up. Showers, washing dishes, dishwashers, breathing (around 1.5 L daily into the house per person), does washing etc thus releasing moisture even if there is no penetrating damp. This moisture also travels and then condenses at a dew point of around 15 degrees celsius - on colder surfaces - like single glazed windows, or cold outside walls causing damp in walls and mould.

Simplest way to get rid of this moisture - open windows daily and ventilate. Not necessarily ALL day, but for an hour or so. If it gets below 16 degrees I shut them, whack the heating on, then its off after 45 mins or so because I am normally too hot it heats up so quickly and efficiently!

Can anyone who knows this better than me explain the merits of opening the window to air the house on a very rainy day? Isn’t the air as moist outside as in? Or is it about air exchange?

(I air rooms instinctively rather than routinely…)

I notice it in the bedroom if windows haven't been opened that day. The body heat/breathing/other mysterious effects of 2 bodies in a bed overnight seem to make the air stale. I like to have bedroom window open for as long as possible, regardless of the season. I open kids bedroom windows daily too. I think it's one of those things you only miss if you do it often, to the point where your nose tells you if air is stale or fresh.

@Bestcatmum I've got a dog, he's 14 and is a smelly little bastard. They say you go nose blind, I wish I would.

Windows opened daily to try and combat his stench.

if only people did science at school.

Enough air for what? It’s certainly possible to get enough not to die of suffocation!

Even on a wet day the humidity outside is lower than inside.

Google Peter Ward and the heritage house website. He does a very good you tube video with cold bottles of beer that explains this - taken out the fridge, one placed outside and one inside house. If you go back to them a few minutes after the inside one is covered in condensation where humidity has condensed on the cold surface. The outside bottle is condensation free - the day he did it was rainy/sleety and very cold.

Its to do with saturation and concentration. Even on a freezing day humidity will be lower outside than in. Similar principle to Osmosis/diffusion etc - a solute will always move from areas of high concentration to less dense areas of low concentration down a gradient.

If you go back to them a few minutes after the inside one is covered in condensation where humidity has condensed on the cold surface. The outside bottle is condensation free - the day he did it was rainy/sleety and very cold.

Surely whether or not the moisture in the air condenses on the bottle is also to do with the difference between the temperature of the surface of the bottle and the temperature of the air. So it makes sense that there would be no condensation on a cold bottle in a "very cold" environment, as nothing has happened to make the water vapour warm enough to condense. (Unless there was condensation all over the place ie dew.)

Inside, the (relatively) warmer water vapour is cooled when in contact with the cold bottle and condenses. Unless you are claiming that the indoor air is saturated, but in that case there would be condensation everywhere.

(Or that is my physics gcse understanding of it!)

Can't remember the last time I opened the windows - it's not warm! I am sitting here in salopettes, two hooodies, a bobble hat and a blanket. if I opened the windows too I think I might die.

Where do you live ? Iceland 🇮🇸

North Yorkshire - feels like Iceland to me!

We ventilate the house fairly constantly, although DH was born in a barn and would have all the windows open most of the time if it was his choice. The bathroom window is always open, the bedroom window almost opposite stays open all night, so there's no risk of suffocation. A window in the kitchen is generally open to minimise cooking smells. In summer all the windows are open as long as there's someone at home.

the bedroom window almost opposite stays open all night, so there's no risk of suffocation

Is that seriously the reason, because you think you might suffocate if the windows were closed?

Bathrooms and our bedroom window are always open. Kids bedrooms opened first thing for an hour or so. Kitchen patio doors open pretty much all day for dogs.

I’d feel claustrophobic with windows shut… I’m aware this is weird!

@garlictwist you're a hardened northerner! Throw those salopettes out and get a pair of shorts on 😏

Ooh love an open window

Don't forget that water vapour needs to cool down to cause condensation not warm up - if it warms it turns to gas in the air.

So yes Temp and relative humidity makes a difference, but more humid air holds more water vapour and this cools when hitting cold surfaces - hence the water on single skinned old sash windows in the morning. All we need to do to prevent this is dilute the humid air with less humid air - ie open windows at least for a time!

Lack of ventilation also causes condensation in walls, particularly in old houses and/or colder outside walls, causing damp. This is called cold bridging.

Don't forget that water vapour needs to cool down to cause condensation not warm up

Sorry yes I meant cold enough to condense. Either way warm water vapour in a house is more likely to condense when it meets a cold bottle than cold water vapour.

I open bedroom windows for an hour at least every morning and am still sleeping with mine open. I also open kitchen windows and living room every day for a while. Houses need to be aired. It's not cold yet.

I open bathroom and kitchen windows daily, for an hour at least. I do the bedroom ones on the weekend whilst kids are eating breakfast. The house does need to be aired but not all day. it's getting cold where I am though.

I open our windows as I hate it when it's stuffy. I open all the bedroom windows each morning to ventilate all the rooms and I open the downstairs ones, even if it's cold outside.

I don't think it's healthy to breathe in stale air all the time.

In my house the humidity is always lower than that outside. Of course that doesn't mean that there is less water vapour as the temperature is higher. But generally when I look on the thermometers/humidity meters the humidity outside is always greater. That may be due to the fact I have more space per person or don't need to do as much clothes drying or just that I use the trickle vents to get rid of the excess - I don't know.

If I open the windows, cold air with relatively high humidity will rush in replacing warm air with lower. The amount of water vapour might be less after opening the windows though, so if I heated the air up again then the humidity might be even lower than it was before - I might try it.

Can't help feeling that a more energy efficient (and cheaper) way of doing the whole process would be not to open the windows and then reheat the air, but to use a dehumidifier to lower the humidity. The running cost of the de-humidifier would probably be cheaper than having to re-heat the air.