I am getting confused.MVHR or better positive input ventilation

[Bosi]

Hi. 

 

We have an old house which is currently under renovation with a small new extension plus we take out downstairs the plaster and ceiling and create a large open kitchen Livingroom area.

 

With a very large (1000l) aquarium the humidity is always too high.

 

So far we had a mvhr from suedwind in the wall, but its performance was not very great, still every morning we have around 70% humidity and open all doors and windows.

Without  it running 80%

 

I wonder if there is a reasonably priced mvhr solution to put in the extension loft which will take mainly out the humidity in the living / kitchen room area, as that is where the tank is, or a wall mvhr from kair

 

But then I read that they even recover the humidity, which is what I want to get rid of. So I wonder if I should instead install in the main loft a positive input ventilation, possibly with a heater to take the edge off on cold days.

 

What do you think would handle the high humidity better please?

 

Thank you for your help

 

Manfred

 

[SteamyTea]

17 minutes ago, Bosi said:

But then I read that they even recover the humidity

I think they can recover the latent heat of fusion from the excess humidity.

There are some that have a porous paper element that allows some transfer of moisture, but I don't think there is enough to worry about.

 

Have you thought of putting an extractor hood over the fishtank. Then plumb it into your existing unit.

[A_L]

hello and welcome,

 

11 minutes ago, Bosi said:

I read that they even recover the humidity

 

not quite, if the extract air is humid enough and the incoming air fairly low temp the water vapour in the extract air can condenses to liquid in the mvhr heat exchanger, In the process giving heat to the incoming air. The liquid water is drained from the heat exchanger via a condensate drain.

 

as to the PIV will there be trickle vents in the humid rooms?

[Olf]

45 minutes ago, Bosi said:

still every morning we have around 70% humidity and open all doors and windows

 

If that is the relative humidity of your local microclimate, MVHR will struggle to get much lower than that. PIV will not make miracles neither.

 

45 minutes ago, Bosi said:

But then I read that they even recover the humidity

Possibly you mean enthalpy heat exhanger? Yes, it can recover moisture from the exhaust, but its purpose is exactly opposite to what you want to achieve: to keep the moisture inside, when drawing cold air would further dry it by warming inside. For that reason, despite higher price, even the UK distributor does not recommend it.

 

46 minutes ago, Bosi said:

What do you think would handle the high humidity better please

Dehumidifier. If aircon based, you get cooling for hot periods for free

[tonyshouse]

MVHR for me , PIV wastes heat big time