MVHR on new ICF build

[deuce22]

Hi.

 

I've been given my SAP calculations and it states that I should be using intermitent extract fans in the kitchen and bathrooms. I'll be starting on first fix shortly and so I'm going through things now. I've been told that the fans wont work properly as I dont have trickle vent in the windows, is this correct?

If that is the case, the next option is MVHR. Somebody I know have just installed this in a 200m2 property and it has cost him approx £1500. My house is around 115m2 per floor over 3 floors (345m2), so I assumed it would cost me double (around 3k).

I've just had a spec from bpc ventilation and the cost for the two options is between 5-5.5k. I've been told by somebody to have 1 unit for each floor as this will be more cost effective and if one fails it doesn't shut it down for the whole house.

I'm looking for advice on what is the best option and what it should roughly cost per m2.

 

Thanks.

[Nickfromwales]

10 minutes ago, deuce22 said:

Hi.

 

I've been given my SAP calculations and it states that I should be using intermitent extract fans in the kitchen and bathrooms. I'll be starting on first fix shortly and so I'm going through things now. I've been told that the fans wont work properly as I dont have trickle vent in the windows, is this correct?

If that is the case, the next option is MVHR. Somebody I know have just installed this in a 200m2 property and it has cost him approx £1500. My house is around 115m2 per floor over 3 floors (345m2), so I assumed it would cost me double (around 3k).

I've just had a spec from bpc ventilation and the cost for the two options is between 5-5.5k. I've been told by somebody to have 1 unit for each floor as this will be more cost effective and if one fails it doesn't shut it down for the whole house.

I'm looking for advice on what is the best option and what it should roughly cost per m2.

 

Thanks.

£1500 is the price of a decent MVHR unit !? Let alone a whole installed system.

 

The requirement for MVHR is not a choice, it is mandated by the number of air changes per hour demonstrated by your blower test result. Have you had one done?

[Happy Valley]

It's not really about cost per m2 more the design of your house. If you have 3 floors it is much more complex to get the pipe runs from the manifold(s) to the rooms if you only have one unit.  

 

MVHR is a no brainer on a fairly air tight ICF build with no trickle vents and no holes in the building. Our system from BPC was £3000+ VAT uninstalled on a 160 m2 2 storey build.

 

It works superbly btw.

[deuce22]

Thanks both for the explanation. I have not had a blower test done, just sent drawings to the company and they've sent back a spec for it.

 

So it's not just as simple as doubling your 160m2 house and that would almost be sufficient for my 345m2 house?

 

How does a MVHR differ from the intermitent fans I've been told to install?

 

 

[Mr Punter]

Get the MVHR spec'd and give this to your SAP person.

 

MVHR differs from intermittent extractors as it uses the heat from stale extracted air to warm fresh incoming air, which it draws in mechanically through a large duct.  The extract and intake air is distributed throughout via a series of ducts and vents to each room.

 

Intermittent extractors just pull out internal air from kitchens and bathrooms and this is replaced with outside air entering through trickle vents at whatever the external air temperature happens to be.

[deuce22]

Ok, so there's no comparison really.

 

Why would the SAP company need to know, that I'm using MVHR over intermitent fans?

[ADLIan]

Because it’s an input into the SAP assessment.