Utility Ventilation

[MikeGrahamT21]

Hi,

 

Trying to decide what to do in the utility for ventilation, after spending many hours airtighting the building. We plan to heat the utility to around 16C (which we are doing already), i've put a humidity monitor in there which is showing 15.4C average, and between 73% and 84% humidty, which seems quite high, though I ran it through an online tool, and found that only equated to 60% at 21C, so maybe not too bad.

 

We plan to have a condenser dryer in there, and also a heated airer, so could do with some way of getting rid of excess moisture.

 

Do i get:

 

1. a dMEV fan such as Vent Axia Lo-Carbon Centra for extract only ventilation (how will this act if the room is airtight?)
2. a Single Room MVHR (Nearest fit is the Vent Axia Tempra P, but the vent pipe will stick out of the wall around 20cm, which could look quite naff)
3. a standard intermittent extractor fan controlled with humidistat
4. Do nothing, though i'm not sure thats an option with Building Control

 

A dMEV or standard intermittent extractor would certainly be the cheaper of the options, but I have no idea where the air would come from, as we have no trickle vents on the doors or windows, and theres no openers on the window. I suppose there will be gaps somewhere for it to come from.

 

Any input greatly received.

 

Regards

Mike

[Declan52]

I have a mhrv extract above my condensing dryer and it takes away  any moisture it produces.

[MikeGrahamT21]

Is this part of a whole house system? In this particular room, the only MVHR possible would be single room, just not sure its worth the extra cost. Would you pay the extra £150 for an MVHR unit over dMEV?

[Declan52]

Yeah it's one of the extracts in my whole house system.

What are you doing about ventilation in the rest of the house???

[MikeGrahamT21]

Well, I don't know if you've seen my other post, but yeah...thats an interesting one. I REALLY wanted MVHR, but it seems our lovely neighbour with her wood burning stove may have put an end to that one, so really not sure what to do about it, at the moment its not a major issue as the house is leaky enough to sort itself out, but hopefully in the future it won't be quite as much.

[Declan52]

I have a nice neighbour like that who going by the smoke has to be burning tyres. If he has it lit and the wind is blowing my way we have no other way round it but to turn the mhrv of. 

Easy and cheapest option would be a humidity controlled fan like you get in a bathroom. Still a hole in the wall but it's either that or the window open.

[MikeGrahamT21]

Yeah, she burns stuff all winter long, which is the most important time for MVHR. I've not totally discounted it, going to pay more attention to where it smells this year for possible intake locations.

 

Yeah, I can pick up a dMEV for £44 (Vent Axia Centra) off ebay, which seems reasonble. Would you say there is little point going for something like a Vent Axia Tempra P (Single Room MVHR) which I can get for £146, but it'll look rather ugly on the outside of the building which isn't great.

[Declan52]

I would go the cheapest option. 

[MikeGrahamT21]

Agreed. I've had a thought, rather than drilling a whopping hole through the wall, I'm going to install fan in ceiling and take it out through a tile vent. If I have any issues with lack of airflow, I'll put another vent in ceiling down other end of room, and either take it to another tile, or just allow air from the loft area into the room. Think I'll go with the continuous dMEV for £44, sounds a sensible option to me

[MikeGrahamT21]

dMEV did the trick, no need for an inlet vent either so there must be some leakage somewhere despite my great efforts, got a bit of smoking cardboard and with all the doors shut the smoke went where it should. Humidity is 67% this morning, the lowest its been since i put the monitor in there, so all good.

[MikeGrahamT21]

Found the leakage points, it's coming in via the composite door, where the latch and locking mechanisms go in to the frame, crazy how badly some products are made, even more annoying as I've got 3 of the same type door.

[Ferdinand]

Has anyone done the heat loss math for one of these DMEVs vs a Lo Carbon Tempra, or taken thermal pics from outside?

 

I guess the Centra is really a hitech, well-controlled trickle vent.

 

I install the Tempras as a default in rentals, but not in bathrooms, and I would be interested.

 

Yes, they do look quite phallic in thinner walls, particularly the extended length version the handyman installed in a normal wall the other day as the only one in stock.

 

Ferdinand

Edited October 28, 2017 by Ferdinand

[SteamyTea]

Can you wire in the fan so it only comes on when the tumble dryer is on?

Then it is only a few Wh when it is needed.

[MikeGrahamT21]

On 28/10/2017 at 16:54, Ferdinand said:

Has anyone done the heat loss math for one of these DMEVs vs a Lo Carbon Tempra, or taken thermal pics from outside?

 

I guess the Centra is really a hitech, well-controlled trickle vent.

 

I install the Tempras as a default in rentals, but not in bathrooms, and I would be interested.

 

Yes, they do look quite phallic in thinner walls, particularly the extended length version the handyman installed in a normal wall the other day as the only one in stock.

 

Ferdinand

I can take a picture from the outside using the thermal camera when it's next really cold, but the utility is only heated to around 16c so you may not get the full effect. I've just put another Centra in our bathroom, to replace one which came on via a PIR everytime we walked in the room and also everytime it was windy, as they sent me the none sealed version of the bloody PIR, so now we are humidity controlled or pullcord with permanent trickle, though you can turn the trickle off if you want via the DIP switches which is quite handy. Even on the slowest trickle, which is almost totally silent, it still shifts a fair bit of air, but is almost totally inaudible.