Dual MVHR Units

[DanJepp]

Hi

 

Im committed to having MVHR as i've not specced trickle vents on my windows (considerable saving per unit!) and i'm looking fwd to having clean fresh air in my new build timber frame house

 

I'm just starting my research into what system to go for so appreciate any shortcuts/advice to this.  My new build is a reasonably large size (5 bed - 365sqm) and initial designs from professionals have steered me towards needing 2 Units for the left and right hand side of the house.

 

One unit was suggested thats large enough : https://www.bpcventilation.com/domekt-r-500-v  but there doesn't seem to be a huge range available

 

Any thoughts/alernative suggestions appreciated

 

Dan

[IanR]

You could consider a small commercial unit. I have an Airflow DV1100.

 

I understand balancing is more difficult with 2 units. I got Airflow to design my system and they were against two smaller units, plus it was cheaper to go with one slightly larger unit.

[Simon R]

We've got the Blauberg SB 550 which is a tad larger than the one BCP recommended at 690 m3. Very happy with the unit and support. The 5 bed kit cost £2046 (not including VAT) in 2019. They also do the system design for free.  If you do go that route make sure you say you're a builder when you create your account on their system to get trade discount (the Blauberg sales guys told me to do this).

https://www.blauberg.co.uk/en/blauberg-large-heat-recovery-ventilation-kit-whole-house-self-build-diy-system-ec-sb-550

[DanJepp]

21 minutes ago, Simon R said:

We've got the Blauberg SB 550 which is a tad larger than the one BCP recommended at 690 m3. Very happy with the unit and support. The 5 bed kit cost £2046 (not including VAT) in 2019. They also do the system design for free.  If you do go that route make sure you say you're a builder when you create your account on their system to get trade discount (the Blauberg sales guys told me to do this).

https://www.blauberg.co.uk/en/blauberg-large-heat-recovery-ventilation-kit-whole-house-self-build-diy-system-ec-sb-550

many thanks will take a look - nice to hear your happy with it

[DanJepp]

1 hour ago, IanR said:

You could consider a small commercial unit. I have an Airflow DV1100.

 

I understand balancing is more difficult with 2 units. I got Airflow to design my system and they were against two smaller units, plus it was cheaper to go with one slightly larger unit.

Thanks - good idea,  

 

I imagine having a larger commercial unit means you can run it at lower capacities - any issues with noise (as assume less of an issue if installed in a school/sports hall etc)

 

Thanks

[Dudda]

It also depends on the layout of these large houses. If the layout results in very long runs then it might be better to have two smaller units. I worked on a very large house which was made up of three different wings so we had three small MVHR units. One in each wing. The house was very airtight at 0.39 air changes.

[IanR]

The DV1100 I mentioned is PH Certified and designed to the same standards as their domestic units, so noise levels are comparable.

 

When the house is occupied I run it at 20% with no discernible noise and switch it down to the minimum 12% when unoccupied. I have the boost set at 55%, which is about the limit for hearing "wind" noise from the outlets, and still no noticeable noise from the unit which is in a 1st floor storage area - all my habitable space is on the ground floor. Boosting at this level clears the bathrooms relatively quickly after a shower, and stops kitchen odours travelling anywhere else in the house while cooking.

I also have a purge setting that I use to help purge heat at the end of a warm day, if I can't open up the roof vents due to rain. That runs at 80%. Sound from the outlets are noticeable if you are within 2m of them and there is a light hum from the unit. I wouldn't describe it as intrusive, but I don't tend to run it for too long on this setting.

 

Since mine is a converted cow-shed, with a 6.5m ridge height, my volume is particularly large in relation to the floor area. From memory it's about 1650m³ within the thermal envelope.

[Conor]

Our house is 315m² and basically split in two with a central hall/stairwell across three stories. So two units is a must. I've two Salda units ready to fit, each one 400m3hr capacity. I'll have 160mm ducts rising from each through the house with manifolds on each floor. It's a lot of kit!!!