System to provide filtered cool air to bedrooms?

[ashthekid]

Hi,

 

I've been looking at installing a MVHR into my project but am now thinking of scrapping that to just a system that provides filtered cool air without any heat recovery extraction to try and save money because the quotes I'm getting are crazy.

Is there such a system that does just that and if so what do people recommend?

 

I basically have extractor fans already position in wet rooms and kitchens so that's covered but I do have rooms without any windows or ventilation that will require some sort of ventilation and also with the whole of the upstairs being in loft space rooms they will be very hot a stuffy most of the time so looking to provide some kind of filtered air system for the family that will utilise the outdoor cool air overnight to naturally cool the rooms rather than your standard air con systems that I cannot have within a conservation area anyway (and I don't have anywhere to put an outdoor unit anyway).

 

[Marvin]

As you probably know it's air in = air out.

So, do you have a drafty building?

Do you have trickle vents in the windows?

Do you have any other form of air being ducted into the building?

 

And general questions which will help to understand if this is a big or small system:

 

I guess 2 stories high?

How many square meters floor area?

 

Questions about your proposed system that just provides cool air:

 

If in the winter ( yes another thing that it would help to know) it gets cold, would you turn the system off and if so how would you obtain fresh air?

 

Help us to help ?

 

Good luck

Marvin

 

 

[A_L]

1 hour ago, ashthekid said:

a system that provides filtered cool air

 

Positive Input Ventilation (PIV) will provide filtered air for the attic rooms for £3-400 but cooling effect of night time air will be limited because there will be little thermal capacity to provide 'coolth' storage for daytime. Providing cooling really requires a heat pump, air-con units with no external box are available, just two grilles on the wall.

 

e.g. https://www.olimpiasplendid.com/without-outdoor-unit

[ashthekid]

@A_L thank you. I have seen those "without outside box" air con units before but ideally don't want a bit unit hung on the wall inside either. Would rather just discreet vents like on a PIV like you suggested. I'm not so bothered about daytime cooling upstairs, more for night time and general health to be honest.

 

@Marvin thank you. In answer to our questions, it's a newly created building albeit built on the inside of an old single skin property that is 200yrs old. Basically a timber frame built inside single skin brick or chalk cob walls. It's not intended to be crafty but it's certainly not airtight. 2 storey for 70% and the remaining 30% being large open plan double vaulted ceiling room. extractor fan points have been located in the obvious wet rooms upstairs and trickle vents are in the rooms with windows but there are a few rooms without any windows whatsoever that will require ventilation to meet building regulation. Approx 380sqm upstairs & downstairs.

Very good question about winter time ventilation in those room without windows. I'm not sure of that to be honest.

 

I did look at partial MVHR which I am still not ruling out because of the benefits. Extract from 3 bathrooms (not kitchen) and ventilate into 4 bedrooms upstairs and 3 rooms downstairs. But only if I could get a decent system like Zehnder Q600 for an affordable price really.

[Marvin]

13 minutes ago, ashthekid said:

@A_L thank you. I have seen those "without outside box" air con units before but ideally don't want a bit unit hung on the wall inside either. Would rather just discreet vents like on a PIV like you suggested. I'm not so bothered about daytime cooling upstairs, more for night time and general health to be honest.

 

@Marvin thank you. In answer to our questions, it's a newly created building albeit built on the inside of an old single skin property that is 200yrs old. Basically a timber frame built inside single skin brick or chalk cob walls. It's not intended to be crafty but it's certainly not airtight. 2 storey for 70% and the remaining 30% being large open plan double vaulted ceiling room. extractor fan points have been located in the obvious wet rooms upstairs and trickle vents are in the rooms with windows but there are a few rooms without any windows whatsoever that will require ventilation to meet building regulation. Approx 380sqm upstairs & downstairs.

Very good question about winter time ventilation in those room without windows. I'm not sure of that to be honest.

 

I did look at partial MVHR which I am still not ruling out because of the benefits. Extract from 3 bathrooms (not kitchen) and ventilate into 4 bedrooms upstairs and 3 rooms downstairs. But only if I could get a decent system like Zehnder Q600 for an affordable price really.

I think you need to be carefull about mixing different systems resulting in them not working properly.

 

As I understand it (and I installed our MVHR) an MVHR system works by controling air in and out of the building and in the box where they cross the temprature is exchanged between the 2.

 

The efficency is related to a few things:

Airtightness including no trickle vents.

Correctly sized units and ducting.

Correct adjustment of the flows from each inlet and outlet.

 

The idea behind the layout of the inlets and outlets is that the air is ducted into the dry areas and out of the wet areas causing the air to circulate.

 

I'll let other people tell you that they have MVHR and open windows on some occasions, and have extractor fans in the kitchen.

However the MVHR needs to be able to work correctly when the windows are closed and the fans are off. 

 

Remember the MVHR or the MV will run for almost 9000 hours a year and so you need it to work as effortlessly as possible.

 

Good luck

Marvin

 

[ashthekid]

So you wouldn’t necessarily recommend a PIV system just to get fresh filtered air into the property along with your standard extractor fans in wet rooms and kitchen?

The windows and rooflights all have trickle vents in them but it’s the rooms that don’t have any ventilation whatsoever that I am probably most worried about and then the upstairs bedrooms during the summer.

[Marvin]

18 minutes ago, ashthekid said:

So you wouldn’t necessarily recommend a PIV system just to get fresh filtered air into the property along with your standard extractor fans in wet rooms and kitchen?

The windows and rooflights all have trickle vents in them but it’s the rooms that don’t have any ventilation whatsoever that I am probably most worried about and then the upstairs bedrooms during the summer.

A PIV system may be your best bet in your situation. This is, of course, quite different from an MVHR system. I was considering the running costs as well. Where roughly is your project? 

[Marvin]

Where would you draw the air from to cool the upstairs loft rooms -assuming from the outside, so the system would not be on during a hot day only during the night?

 

 

 

[ashthekid]

I could have it running continuously or on a timber but yes primarily during the night during the summer time but also at intervals to keep the air inside filtered and fresh.

Project is located in Hampshire. 

[ashthekid]

So I've discovered a few different PIV units:

• Vent Axia Lo Carbon PoziDry Compact Pro PIV Positive Pressure Unit - approx £300

• Blauberg Fresher 50 PIV Filtered Air Condensation Control Fan(single room only) - approx £200

• Nuaire FlatMaster or Dri-365(which both can be located in a cupboard rather than a loft space) - approx £600

Anybody had any experience with any of these units?

[markocosic]

For ventilating and heating/cooling bedrooms:

 

- Fit the (noise making) air conditioning to the upstairs landing

- Use a ceiling cassette that has a "fresh air inlet" for example:

https://www.saturnsales.co.uk/Mitsubishi-FDTC35VH/1-Cassette-Air-Conditioning.html

- Fit EXTRACT vents to the bedrooms

- Run ducting in attic to an inline fan

- Connect the outlet of the inline fan to the ceiling cassette

 

This will cool (or heat) the air in the landing, then suck the cooled (of heated) air under the doors and into the bedrooms, and exhaust the extracted air back into the ceiling cassette for spreading around and cooling/heating again.

 

If you're not worried about heating/cooling the air then just hook the outlet of the inlet fan to a supply cent in the landing.

 

 

Keep an eye out on fleabay too. MVHRs come up from time to time at the kind of money that you're looking at just for fans...

 

My first attempt was unsuccessful - I got f**ked over by Brookvent (the used MVHR that I bought had a dead fan motor but Brookvent refuse to sell spare parts and refuse to allow the fan manufacturer to supply anybody but Brookvent)

 

My second attempt has been successful - I've just picked up a pair (one for our house, one for the parents house) of these @£275 each. Removed by the MVHR installer at the builder's expense and replaced with a more compact unit because the boiler didn't have sufficient clearance to the MVHR unit and was refused a certificate on its first service.

 

https://www.ebay.co.uk/itm/265297462305