MVHR Design And Install

[Gus Potter]

2 hours ago, JohnMo said:

How it works, day time, bedrooms not used, trickle vents almost fully closed. Downstairs rooms have people so the vents start to open in response to rising humidity, fans draw the air across the room, through corridors and out the house. At night the effect swop, now bedroom trickle vents open and downs close. No-one in house, all trickle vents go to min opening

This is elegant at first glance. It might float your boat.. but I honestly despair at times. 

 

You write a lot of good stuff John but what about say a young couple that come to buy your house. Will you make them aware of any potential maintenance issues? 

 

Now you may have all your faculties at the moment and I'm sure you think this is your forever home, but when you get less "sharp" and need folk to maintain your house who may be less dilligent.. what then?

 

I totally get that your house is your hobby.. but in my day job I need to give Clients best advice. That includes protecting their asset. 

 

I do love you technical grasp and hope you don't mind me taking a more general view.

 

 

 

 

 

 

 

 

[JohnMo]

5 hours ago, Gus Potter said:

This is elegant at first glance. It might float your boat.. but I honestly despair at times. 

 

You write a lot of good stuff John but what about say a young couple that come to buy your house. Will you make them aware of any potential maintenance issues? 

 

Now you may have all your faculties at the moment and I'm sure you think this is your forever home, but when you get less "sharp" and need folk to maintain your house who may be less dilligent.. what then?

 

I totally get that your house is your hobby.. but in my day job I need to give Clients best advice. That includes protecting their asset. 

 

I do love you technical grasp and hope you don't mind me taking a more general view.

 

Absolutely nothing wrong with a dMEV system, what maintenance, there is none? The trickle vents are controlled by a membrane that contracts or expands to variable moisture levels, zero inputs from anything else. The fans are commercial available bathroom fans. Greenwood make a nice one, but many others available. Way less maintenance than MVHR.

 

Zero faculties needed, fit it walk away. That cannot be said or MVHR as you need to change filters etc.

 

5 hours ago, Gus Potter said:

young couple that come to buy your house. Will you make them aware of any potential maintenance issues? 

Same as any other house, I have owned around 10 houses, no one has ever told me anything about maintenance ever. But as said above dMEV, what maintenance?

[Nickfromwales]

5 hours ago, JohnMo said:

Way less maintenance than MVHR.

MVHR has centralised filtration at the unit. Cleaning or replacing the filters can be done faster than making a cup of tea from scratch.

 

Multiple units in different locations adds to this ‘problem’, as anything that air flows through will attract dust that needs removing, so that is at every trickle vent, plus the fan filters, worse if the fan is in an attic space.

 

MVHR is the better solution, afaic, because of the ease of (self) maintenance and the heat recovery.

[JohnMo]

18 minutes ago, Nickfromwales said:

Cleaning or replacing the filters

Your preferred Brink MVHR, filters from a quick look are £70+, depending on area you live, that could be twice a year expense. So may only take the time it takes to make a cuppa, but it becomes an expensive cuppa.

 

Had a dMEV fan running in a summer house a couple of years, nothing has been done, nothing has been needed, could replace the whole fan nearly twice for the cost of your filters.

 

28 minutes ago, Nickfromwales said:

MVHR is the better solution, afaic,

MVHR isn't the only solution, and not always the correct or only solution.

[Nickfromwales]

28 minutes ago, JohnMo said:

filters from a quick look are £70+, depending on area you live

In your own words, “look harder”

 

[Adrock]

I've almost certainly gone too far down the airtight rabbit hole to consider trickle vents now, I have two new windows and a door installed which don't have them. MVHR is going to be the answer.

 

After that quote I think I'll definitely be doing it DIY though, like almost everything else in the house.

 

Time to build a bill of quantities and spend some money.

[JohnMo]

2 hours ago, Nickfromwales said:

In your own words, “look harder”

 

I did look harder and dismissed G4 for both supply and extract as that is not the normal offering, for a new unit, it's the supply filter that bumps up the cost.

 

But OP wants to go MVHR route anyway.

 

But here is a proper study completed a while ago, worth a read for anyone interested.

Atamate_SDAR+Paper+2019+(1).pdf

 

[Adrock]

Cheers @JohnMo, I'll give that a read.

 

I'm going to have a play with my house plans over the next few days and I'll try to remember to share the drawings. All opinions and input is valued, it's why I keep coming back with my problems. 

 

Just imagine if architects could actually have these kinds of details as standard.

Edited 8 hours ago by Adrock

[torre]

This Passive House Trust article makes the case that:

 

Quote

MVHR systems are, in fact, beneficial in nearly all domestic situations, either new-build or retrofit.

 

[Indy]

19 hours ago, Adrock said:

 

Materials are £10k and install £6k, the house will be just over 200m2 across four levels one day. Plenty of work to get there though.

Not too far off what we were quoted - though ours is over 2 levels and simpler though slightly larger floor area (300m2). £6.5k for parts and £4k for install. 

 

I am seriously considering going down the route of DIY install - i.e. get them on site for a toolbox talk and then do the bulk of the labour myself. Then have to call them back for a commissioning visit anyway - total cost should be £1k + my time. 

 

I know people on here do talk about how they've DIY'd the whole thing but for most people, that's not really an option. BC has specified that the commissioning must be done by a qualified company as it forms a part of the fabric of the building, and was the only way they'd say no to removing the extractor fans and trickle vents from the property. 

[Adrock]

37 minutes ago, torre said:

This Passive House Trust article makes the case that:

 

 

 

That's an interesting article, thanks.

[Adrock]

19 minutes ago, Indy said:

Not too far off what we were quoted - though ours is over 2 levels and simpler though slightly larger floor area (300m2). £6.5k for parts and £4k for install. 

 

I am seriously considering going down the route of DIY install - i.e. get them on site for a toolbox talk and then do the bulk of the labour myself. Then have to call them back for a commissioning visit anyway - total cost should be £1k + my time. 

 

I know people on here do talk about how they've DIY'd the whole thing but for most people, that's not really an option. BC has specified that the commissioning must be done by a qualified company as it forms a part of the fabric of the building, and was the only way they'd say no to removing the extractor fans and trickle vents from the property. 

 

My dilemma is half of the house won't be ready to install the MVHR system into for at least two years, this is a long term project. I don't suspect a company will be willing to come and install piecemeal.

 

Which is why I was clear in my initial correspondence, the quote seems like a rough and ready count and budget thrown together to get me off their backs after I chased for a response.

[JohnMo]

1 hour ago, Indy said:

BC has specified that the commissioning must be done by a qualified company as it forms a part of the fabric of the building,

Actual rules say calibrated and certified equipment. But I used the same person that did the air test as he did MVHR commissioning also. But everything else was self designed and installed. Pretty easy once you get your head around it.