Ventilation and humidity control in an old house - what are they options?

Sunbed

Sunbed

Sunbed

Soldato
Joined
29 Mar 2007
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Manchester
It seems like every planned 'upgrade' for my house is conspiring to increase the chances of damp problems in the future. For example, replacing the original single glazed windows with new wooden double glazed units will reduce ventilation, as will a new door. Also repointing the house with cement mortar and plastering with gypsum based plasters will supposedly stop the house 'breathing', although I get so many conflicting views on this the topic could have its own thread.

So what can I do? I obviously want to minimise heat loss but I also need ventilation to stop the house feeling damp.

I started by researching Mechanical Heat Ventilation Recovery systems. In theory, this would solve all my problems. A draught proof house with controlled ventilation and humidity control seems pretty good, but then I realised just how hard it is to get a house properly draught proof, and how ugly some of the ducting can be. It's not impossible, but too difficult for me.

Is there some kind of continuous dehumidifier that can be ducted to various rooms in the house? I currently have a Meaco 20L dehumidifier that I wheel around the house. It's a good bit of kit but it's doesn't exactly fit in with the intended period styling. Is there something more discreet?
 
I've heard great things about those Nuaire's as well, planning on getting one fitted in the new year myself.
 
That looks pretty good. But am I right in thinking it's just a fan? It's not actually extracting moisture out the air at all?
 
It pushes your damp air out replacing it with less damp air.

If you want a full air conditioning system that condensates and drains the moisture in the air you're looking at a few thousand to tens of thousand for a full system.
 
OK thanks. I'm not sure that I do need that but just for my understanding, what type of system would that be? Can you give an example?
 
Sunbed said:
That looks pretty good. But am I right in thinking it's just a fan? It's not actually extracting moisture out the air at all?
Click to expand...

It's a very quiet filtered fan that creates a very slight positive pressure inside of your home. This forces the humid air out through any gaps there might be and replaces it with dry filtered air.

They cost pence to run, and basically just sit in the loft doing their thing for years on end maintenance free, and are apparently very good at drastically reducing condensation.
 
Why are you repointing with cement mortar? What kind of stone is it?
Tbh I wouldn't spend any more money than you need to until you understand what the house is doing after the upgrades, you might find that there is enough air movement to stop any damp build up or feeling of damp...
 
the_r_sole said:
Why are you repointing with cement mortar? What kind of stone is it?
Tbh I wouldn't spend any more money than you need to until you understand what the house is doing after the upgrades, you might find that there is enough air movement to stop any damp build up or feeling of damp...
Click to expand...

It's a solid brick wall, so I'm getting mixed views on how it should be repointed. Some say lime mortar, others say weak sand cement mix is fine. I'm more convinced about the lime plastering though, as I can see how this is more likely to create a moisture barrier.

You're probably right on your second point. I may be overthinking things too soon. I will keep the PIV in mind though, as it would have the secondary benefit of drawing in much needed fresh air to the attic.
 
I would go with the lime pointing and install a couple of fans in the bathroom and kitchen which switch themselves on when the humidity gets to high. Is the building listed?
 
Those drimaster are brilliant removing mold but there are also very good at removing heat and will soon make a room cold.

Also depending on the shape of the house you might need more than 1 machine or vents.
 
Thread resurrection...

There is a heated Drimaster available that should offset some of the cooling nature of the air being pumped into the house. I have just ordered this one to be fitted into our property that currently has some major condensation issues (that could well lead to damp issues). Have only read good things thus far; we shall see....
 
If theres one thing I've learnt over the past year or so looking into the correct ways to insulate and ventilate... it's the fact most people don't have a clue, even so called professionals.

There are so many conflicting views on the matter, it's quite daunting figuring just how to tackle it.

Previous owner here has used cement mortar over all lime based mortar (stone built house), then stuck insulation-backed gypsum PB in front. Huge problem and one I'm still tackling stage by stage.

Not long finished the loft... which again, had no ventilation and insulation stuffed into all crevices. Moisture levels on the average timber up there was 15-20%, not good! Perfect for woodworm. It's now insulated properly and ventilated, timbers have dropped to 7-12%. Much better.
 
Mechanical heat recovery overcomes the cold air issue of those drimasters. easy ish diy job too.

Manrose HR-100-R is £220 online as an example, add some ducting and 2 holes out (use tile vents in the roof is easier)
 
What are peoples thoughts and experiences of the nuaire system after owning a few months?

I'm struggling with humidity levels and some condensation issues in our old house so thinking of getting one
 
Hi, had mine a few months now so can post some thoughts.

Briefly, we had a fairly significant condensation issue. The windows were soaking if temperature outside dropped much below 10 or so. We would also get some on walls (probably an issue with walls too as they were too cold).

Installed pump and put it on middle setting. You can barely hear it, and if you put your hand right next to it you can just about feel air movement. There is no draft.

First night after install was cold, and next morning there was some condensation on windows but not as much as before. Next night was really cold, sub zero, and woke up to clear windows. It's been like that ever since.

I'm not sure if the heating is worth it as the air out pumps out feels cool, but it certainly works. Recommended.
 
Thanks guys. SO the experiences are largely positive? Just been checking out the Mr Venty ECO2 Air. Beyond appearance both the Mr Venty and NUAIRE are essentially the same thing? Any factors either way beyond cost?
 
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