My plan for MVHR

[Coanda]

I've been planning and I've drawn up this sketch, pretty close to scale.

 

The house is just under 100m2 so a small job really.

 

Points one and two are existing kitchen extractor, three and four are existing bathroom extractor fan.

 

I plan to repurpose the bathroom extract to go to the mvhr unit and install a second extract in the kitchen.

 

I'm thinking probably not a good idea to suck cooker waste into the MVHR?

 

One input in each bedroom and living room.

 

Since I'll have three inputs and only two extracts, should I have an extract in the attic?

 

I haven't decided on the outside exhaust and intake yet. 

 

Do I need to insulate the intake or just the warmer output?

 

[ProDave]

Re kitchen and cooker.  Fit a recirculating cooker hood with a filter and then position the kitchen extract a little away from this.

[Coanda]

The red dot in the centre of the kitchen ceiling is where I plan to put it. So it will draw equally from both doors.

 

[Conor]

Need to insulate all runs in the uninsulated attic 

Not sure what you mean by "repurpose" the existing bathroom extract but you want to start with all new ducts and plenums / air valves.

Keep the kitchen extract a couple metres away from the hob and place in such away to encourage airflow away from the other spaces - e.g. towards point 1.

Double up the airflow from the extract kitchen to balance the system. You might want to run two ducts to this.

For external ducts, you want these to be as short as possible and for the vents themselves to be about 2m apart.

 

Edited October 29, 2023 by Conor

[Coanda]

21 minutes ago, Conor said:

Need to insulate all runs in the uninsulated attic 

 

ok but for curiosity what is likely to happen if the intake isn't insulated?

21 minutes ago, Conor said:

Not sure what you mean by "repurpose" the existing bathroom extract but you want to start with all new ducts and plenums / air valves.

I just meant I would use the existing hole in the ceiling rather than make another one. I'll have to enlarge it some.

 

21 minutes ago, Conor said:

Keep the kitchen extract a couple metres away from the hob and place in such away to encourage airflow away from the other spaces - e.g. towards point 1.

Double up the airflow from the extract kitchen to balance the system. You might want to run two ducts to this.

For external ducts, you want these to be as short as possible and for the vents themselves to be about 2m apart.

 

ok thanks

[MikeGrahamT21]

Risk of condensation forming on any uninsulated pipes in a cold loft as the air drawn in will be much colder than ambient in the loft

[Coanda]

OK I get it now. just having a senior moment.