Downdraft extractor or over-hob?

[Lincolnshire Ian]

Hiya

We have started designing our kitchen and have faultered at the design of the hob extractor. 

We have a MVHR system, but want a supplimentary hob extractor. The kitchen has a vaulted ceiling which means a "traditional" design over-hob extractor can't butt up against the ceiling for a clean design. We also aren't planning to have any wall cupboards so an extractor built into an over-hob cupboard wouldn't work either. 

We have looked at venting hobs but are worried that they won't have enough umphh to control the steam and are massively overpriced. 

Any help would be appreciated particularly with over-hob extractors which look nice "free-standing" on a wall with no cabinets or vented hobs. 

Thanks 

[JohnMo]

1 hour ago, Lincolnshire Ian said:

control the steam

Your MVHR will do that on its own. We only use the extractor on rare occasions now (smelly stuff and only on low) MVHR does a good if it on it own. A house with MVHR isn't the same as a normal house with intermittent fans. House feels and act differently.

 

Anything else is a design thing down to personal preference.

[Tetrarch]

We* use our Neff Downdraft every time the hob is used. It has a setting that adjusts automatically to accomodate the amount of steam that is being generated. Ours is on an island with a large rooflight over part of it, so keeping the ceiling clear was very important to us aesthetically

 

We actually went to the Siemens demo kitchen to see the identical downdraft hob in action and it has proved as effective in practice as it was in the showroom. THEY ARE NOT CHEAP, but this was an early line item in our budget and we got a great cashback from Neff by buying multiple items in their annual Autumn offer. We had them in boxes for nearly 8 months before they were installed. 

JohnMo is dead right about the MVHR and humidity. Our MVHR inlet is positioned at the left-hand corner of the pic below. It has two extract pipes in it. We would use the "boost" function but I haven't found a way to make my Alexa+Shelly switch work yet and it seems to work perfectly well without

 

Regards

 

Tet

 

[CJER]

Hi, I found your post and was hoping you could let me know where your ducting for the island sits under your floor, we're currently looking to have one installed and are rebuilding the floor due to an extension, have you gone above/below DPM, we're looking to take the ducting under our new sub-floor.

[Tetrarch]

6 hours ago, CJER said:

Hi, I found your post and was hoping you could let me know where your ducting for the island sits under your floor, we're currently looking to have one installed and are rebuilding the floor due to an extension, have you gone above/below DPM, we're looking to take the ducting under our new sub-floor.

 

Our downdraft has no external ducting. The post-filter exhaust vents through the plinth into the room. We have MVHR that gets rid of the moisture as a whole-house solution but we have a double extract over the island (you can see it above the bottom left corner of the island)

Regards

 

Tet

[Dave Jones]

On 16/11/2025 at 15:15, Tetrarch said:

We* use our Neff Downdraft every time the hob is used. It has a setting that adjusts automatically to accomodate the amount of steam that is being generated. Ours is on an island with a large rooflight over part of it, so keeping the ceiling clear was very important to us aesthetically

 

We actually went to the Siemens demo kitchen to see the identical downdraft hob in action and it has proved as effective in practice as it was in the showroom. THEY ARE NOT CHEAP, but this was an early line item in our budget and we got a great cashback from Neff by buying multiple items in their annual Autumn offer. We had them in boxes for nearly 8 months before they were installed. 

JohnMo is dead right about the MVHR and humidity. Our MVHR inlet is positioned at the left-hand corner of the pic below. It has two extract pipes in it. We would use the "boost" function but I haven't found a way to make my Alexa+Shelly switch work yet and it seems to work perfectly well without

 

Regards

 

Tet

 

 

have exactly the same. really wish I had ducted it.

 

It would take some thought though as the duct would defiantly condensate and would need to go uphill at somepoint to connect to a external vent and there would be pooling of condensation with the associated smells.

 

 

 

[Tetrarch]

1 hour ago, Dave Jones said:

 

have exactly the same. really wish I had ducted it.

 

It would take some thought though as the duct would defiantly condensate and would need to go uphill at somepoint to connect to a external vent and there would be pooling of condensation with the associated smells.

 

 

 

I had exactly the same concerns about the duct and have none of the regrets that you do. Why do you wish you HAD ducted it? The only weird thing is the draught from under the island

Regards

 

Tet