New member with problems.

[Coanda]

I bought an old 30s house about 5 years ago. Single glazed sash windows, fireplace in every room, no insulation, T&G floors with ventilated space under.

I closed up the fireplaces except one, where I installed a wood burner, cause I have enough free wood for it. I installed double glazing, PVC front and back doors, covered the leaky T&G floors and insulated the roof space.

 

So soon the RH was in the 70s and co2 levels with 2 occupants +cat were in the 2000ppm range.

 

So I ran a dehumidifier to reduce the RH but that doesn't help the Co2.

 

If I open the windows Co2 falls but RH rises.

 

I put some MV in for an experiment. I extract through the bathroom and input to the bedroom.

 

The input fan runs around 180 m3/h. The extract fan doesn't have info on it but I think it's similar.

 

I have a co2 meter which shows over 2000 ppm when the bedroom is occupied by two people and no fan and 800 when occupied by two people and both fans running.

 

I've been running them for a week or so and they don't seem to be having any effect on RH.

 

What should be my next step? Add MV to all the rooms in the house and if it's a success then add heat recovery?

 

 

 

 

Edited October 26, 2023 by Coanda

[ProDave]

Fit MVHR to the whole house, which will ventilate it well and recover most of the otherwise wasted heat with ordinary fans.

 

Having lived several years in our house with MVHR when visiting a relative last week we both noticed how stuffy their house was and needed to open a bedroom window each night to get adequate ventilation.

[Coanda]

I have pretty much decided that,that is the only option.

 

luckily, the house is small, under 100 m2 and the roof space gives access to all rooms.

 

There's even a small attic room boxed of and somewhat insulated.

 

[ToughButterCup]

YooChube is your friend here.... a good few videos showing how others solved exactly the same problem.....

Good luck

 

[Coanda]

I guess you guys have heard all these questions over and over but say I put a system in and ventilate the place real well, I know from my short experiment that the Co2 levels will come down, but will, over time the constantly moving air reduce the RH?

[JohnMo]

Getting the RH down does take a while, as the damp permeates the whole structure.  MVHR isn't the only solution, the other is MEV, but with humidity sensing extract points and humidity inlets, these can be trickle vents on the window or through wall.  The system only really extracts air when its needs too, and only at the ventilation rate it needs.  The fan speed modulates based on the extract nozzles that are open.  It does not recover heat, but this benefit is offset with lower overall running costs and only running as required.