Adding MVHR late in the day

[bmj1]

We're looking at adding some MVHR quite late in the day... (ceilings already up, plastered and painted, walls painted/tiled, we've already moved in and are finding the master bedroom quite stuffy).

 

This minimises what we can do in terms of ducting runs (without damages and so costs being prohibitive).

 

Floor plan showing master bedroom/dressing/ensuite here:

 

 

I was thinking to do the below, i.e:

 

- MVHR unit in the ceiling (above joinery)

- duct straight outside for the in/out

- extract out above the shower in the en-suite

- fresh air into the master dressing room

- drainage straight out into the guttering (outside)

 

From those with experience, do we think this will be sufficient to create a flow of fresh air throughout the master bedroom ?

 

 

Thank you in advance !

[JohnMo]

44 minutes ago, bmj1 said:

From those with experience, do we think this will be sufficient to create a flow of fresh air throughout the master bedroom ?

Maybe a bit of a nightmare without lots of deconstruction. And if you don't design correctly may not solve the issues of the whole house 

 

What is your current ventilation strategy ?

 

Trickle vents?

Fans in wet rooms, intermittent or continuously on etc.?

[bmj1]

4 hours ago, JohnMo said:

Maybe a bit of a nightmare without lots of deconstruction. And if you don't design correctly may not solve the issues of the whole house 

 

What is your current ventilation strategy ?

 

Trickle vents?

Fans in wet rooms, intermittent or continuously on etc.?

 

We've got an mvhr unit on the ground floor bring fresh air into kitchen and extracting air from toilet/boiler cupboard and under stairs.

 

The rest of the house has trickle vents that we can open and close as needed.

 

My thinking was to install this in the master bedroom area and then close the trickle vents in that area.

 

We've got dmev fans in the other wet rooms running continuously.

Edited Wednesday at 17:45 by bmj1

[Iceverge]

To beat the same drum again. 

 

How about ditching the idea of MVHR and using a couple of dDCV fans instead. 

 

They're cheap enough that you could buy them and give it a go to see if it helps. 

[G and J]

My MVHR knowledge is limited to planning our forthcoming build, so please bear that I’m mind when reading the following:

 

You state that you find the master bedroom quite stuffy.

 

I’m assuming that simply opening windows and turning the heating up (which was our architect’s suggestion when I mentioned my intention to instal a MVHR) isn’t an option, as you’d have done it by now.  
 

May I ask how airtight your house is?  I ask as I think this is a fundamental….

[JohnMo]

1 hour ago, bmj1 said:

We've got dmev fans in the other wet rooms running continuously.

That should be all you need. If you have trickle vents in wet rooms these need to be always closed. If the are open, the fan just sucks air via these trickle vents and then just blows it outside.

 

Do you have an under cut at the bottom of the bedroom and wet room doors, so air can flow beneath? You only need 5 to 10mm. Then the flow path is in the trickle vents, across the room, under bedroom door, wet room door, across wet room and outside.

[bmj1]

1 hour ago, G and J said:

My MVHR knowledge is limited to planning our forthcoming build, so please bear that I’m mind when reading the following:

 

You state that you find the master bedroom quite stuffy.

 

I’m assuming that simply opening windows and turning the heating up (which was our architect’s suggestion when I mentioned my intention to instal a MVHR) isn’t an option, as you’d have done it by now.  
 

May I ask how airtight your house is?  I ask as I think this is a fundamental….

 

Very. We dry lined with insulated plasterboard and it's a new build.

 

And yes the doors are undercut. 

 

I'm inclined to give it a go unless someone tells me otherwise

[Redbeard]

How 'very' is 'very'? Have you had a test?

 

You say

4 hours ago, bmj1 said:

The rest of the house has trickle vents that we can open and close as needed.

 

My thinking was to install this in the master bedroom area and then close the trickle vents in that area.

 

We've got dmev fans in the other wet rooms running continuously.

 

So is the stuffiness in the bedroom happening even with dMEV running and trickle vent(s?) in that room open? 

[bmj1]

18 minutes ago, Redbeard said:

How 'very' is 'very'? Have you had a test?

 

You say

 

So is the stuffiness in the bedroom happening even with dMEV running and trickle vent(s?) in that room open? 

 

Yes exactly.

 

Not done the test yet, will be interesting to see.