Water filters

[pseudonym]

It's a HA block of flats winterprep - for over 55s, high amenity/high rent. They have people coming round testing showerheads for Legionnaires etc and testing the temp of the water, so it can't be anything harmful. Its just horrible. I googled it "black slime on showerheads & taps" - and seemingly it's not the water, it's airborne - so we've started running the extractor fans inside the showerroom and the kitchen a lot more. But I still don't like the idea of a watertank up in the roofspace For now we've just bought a load of 5l bottled water and working on an easier way to use it. Probly a big jug in the fridge door, refilled daily - but a lot of work for the poor hubby

I use empty squash bottles and Nalgene bottles and rotate out. Minimum of 5 1/2 litres at any time. refill once one is empty and take out the next in queue.

[Frnc]

Ironically, and counterintuitively, cold days are often a good day to open the window for 5-15 minutes. This will swap a lot of the air in the room with outside air. Keep door shut. Cold air can't hold much water vapour, so as long as the outside humidity isn't very high, it's likely to have a lower absolute humidity than the air in your bathroom or kitchen.

Today's not particularly cold, but the AH outside around 2pm is going to be significantly lower than in my house, so I plan to open the windows then.

Weather websites always quote Relative Humidiy. You can convert it to AH here https://planetcalc.com/2167/#google_vignette

Suppose air outside is 13°, 62% RH. That converts to 0.0071 or 7.1 g/m3. This is almost certainly lower than in your house. AH in my house varies around 8-11 depending on room, time, weather etc. Below 10.5 is ok. Also you want the RH in your house lower than 60. If the AH is, say, 10.5, and you open the window, AH will come down. Shut the window after 10 minutes or so. The new air will warm up. The overall RH should come down a bit. Keep doing this and over time your room will be less damp.

Also run kitchen extractor when cooking and boiling kettle. Don't dry clothes indoors if you can help it.

[Frnc]

Use a digital thermometer that shows RH in affected rooms, and try and keep it below 60%. One way is as I said - ventilation, and reducing water vapour sources. Another is raising the temperature. This doesn't reduce AH, but it should reduce RH, as the same AH in warmer air has a lower RH.

Another method of course is a dehumidifier, but they get expensive to run for long periods regularly.

[diamond lil]

I use empty squash bottles and Nalgene bottles and rotate out. Minimum of 5 1/2 litres at any time. refill once one is empty and take out the next in queue.
[/quote]


That would work pseud ta. Saves the money on a big jug anyway.

[diamond lil]

frnc it would be a waste of time running a dehumidifier in a wet room.

[Frnc]

frnc it would be a waste of time running a dehumidifier in a wet room.

Not at all. A dehumidifier will lower the AH and the RH. It might take a while, but it will. Every time you empty it, that's several litres of water removed from the air. It's very satisfying actually.

But if the air outside has a lower AH, it's much cheaper to open the window. Also, bathroom extractors are a good option. So is a kitchen extractor, but they are much higher power draws, so don't run it on max for hours.

Do you understand how AH works? It's critical. I'm not opening the prep room window this morning, even though the RH is 70, because the AH outside is higher than in the prep room, so it would do more harm than good to let it in.

Warm air can hold more water than cold air. So an AH of 10g/m2 in a warm room might give an RH of 50%, but the same air cooled might have an AH of 95%, and be close to dew point. Indoors we are mostly concerned with RH, but we need to know if the AH outside is lower than the AH inside, to know whether to open the window. If it is, bringing it in will lower RH inside.

[GillyBee]

I guess humidity is the other reason bathrooms were traditionally rather chilly with an open window except when actually takkng a bath.
30 mins of airing the room every day may help a lot.

[Frnc]

15 minutes is enough. But if you do it when the Absolute Humidity outside is greater than inside, you are making the room damper. Unfortunately, all weather websites quote Relative Humidity, so you need to convert. This morning, AH outside is 10.0. This is exactly the same as in my bedroom, and higher than in my prep room, so opening the windows would make the house damper.

But later on, at 14.00, RH is down to 55, T is 12, so AH is only 5.9. So I will open my windows then.
https://planetcalc.com/2167/#google_vignette
Divide by 1000 to get g/m3.

[Frnc]

Today's an interesting example. Outside is 15°, 93% Relative Humidity, which converts to Absolute Hmuidity of 12.0 g/m3. This is high, about the same as in my room, and higher than in the cellar and the prep room. So opening the window in the prep room would be a bad idea. Later, it will drop a bit below my room, so I could open my window for a bit, but not the others.

Cause of the high AH outside is mainly the unusual warmth for this time of year. Warm air holds more water vapour. 90% at 15° is much more humid than 90% at colder temperatures. At 0°, 90% air has an AH of just 4.4g/m3, compared to 12 this morning.

Knowing AH indoors and outside is mainly to know whether to bring outside air in. If it's lower outside, bring it in!