High moisture ground floor flat - ventilation systems?

[DangerDangerHighMoisture]

Hello. Hoping someone might have experience and can advise.

We have a ground floor flat. 1970s build, breeze block walls, concrete floors. It's small 2 bedroom.

It suffers from high moisture levels. We're confident it's not water ingress or a leak. Just the construction of the building, a damp climate. It has air vents in each room.

Running a dehumidifier does the job pretty quickly, but the levels rise again if its not running. It's a pain moving it from room to room, emptying it etc. We'realso not always here

Do we have any permanent inbuilt options? There's no loft space. Does a positive input system simply draw in fresh air and remove air from inside? I'm thinking that wouldn't help as the air outside is often damp itself? Do they come with a dehumidifing function? Would a unit in the living room cover all rooms (it's a very small flat).

@PigletJohn ?

Thank you

When do you run the bathroom extractor?

How do you dry and air your washing?

How big are the vents, and when are they opened?

Thank you for responding.

The bathroom extractor runs when the light is on. We leave it running alot.

We don't really do washing here.

The vents are slightly smaller than a sheet A4 paper, we leave them open all the time.

The dehumidifier took our bedroom down to 50 last night fairly quickly. This morning (it's raining, we had the window open) it's back up to 80.

bascially you have described what a positive input does.

It draws in colder, hopefully lower humidity air from outside. Which forces out warmer higher humidity air from inside. That has two effects. It lowers the in house humidity, but also cools the house. So you have to use heat to make up for that.

As the pp says, by fair the best way to lower humidity is to get rid of high humidity air at the source (bathroom, cooker hood) by extraction. It's cheap and efficient.

One thing you could do is that most of the more expensive dehunidifiers will drain externally and not to the internal tank. My one (meaco) will also operate to target humidity. So you could for example drain externally and just set a target humidity while you were away.

Another thing to do is limit your living humidity more. So making sure you don't leave pans on the boil for ages with steam without it being extracted, keep the bathroom doors closed and extract straight after you have bathed/showered and also make sure surfaces have been wiped down and all extra water on the shower door pushed down the plughole (it is this thin layer of water spread out over a large surface area that evaporates to cause high humidity).

Thanks for the reply GasPanic

There's not much else we can do to minimise moisture creation. The bathroom/hob have extractors. We don't really do washing there. We have the heating on year round etc.

@PigletJohn thoughts on input systems? I don't understand how just bringing air in from outside helps significantly, as surely it's just damp outside air??