Are you pleased with your MHVR or an expensive white elephant?

[Haku]

I'm just planning 4 timber frame houses and am in two minds over MHVR. The houses have bifolds along one full wall of the kitchen/diner and also the long lounge wall and all beds have big windows so my instinct is the windows will be thrown open whenever it is warm. The houses will be well insulated though so I'm trying to think about whether they will overheat and does the MHVR add value. Looks like a fully designed & installed system is 5-6k which would pay for PV panels a couple of aircon units and a car charger instead. 

 

Has anyone recently built a TF house in the SE England and regrets not fitting MHVR?

Has anyone recently built a TF house in the SE England and regrets fitting MHVR and wishes they'd put the money into something else?

 

Any opinions gratefully received. I have no experience of living with MHVR and whilst it looks interesting on paper I'm struggling to find a financial justification or indication that it improves the iar quality in the house enough to justify. 

[ProDave]

Not your target location, but I live in the eastern Highlands, probably one of the coldest parts of the UK, and I am running at sub £250 annual heating costs.  That would no doubt be a LOT lower if this same house was in the SE.  I would not have achieved such a low heating bill without mvhr.

 

Summer overheating is very likely to be an issue with all that glass in the SE so I would be wanting lots of PV so at least the inevitable active cooling can be run for free in the summer. 

[nod]

We didn’t put MVR in our first build 

Mainly due to a friend telling us it was drawing fumes in from a neighbors fire 

I’d pretty much decided to fit MVR in our next two 

Visiting a friend today has made us think twice 

He’s had two years problems with his MVR Latest being it knocks itself off at 13c Someone is going to fit an external heater to it ?

When we left my wife asked If we couldn’t spend the money elsewhere Is it just Something else to go wrong 

I suppose the planning and fitting would play a big part in how worthwhile it is 

 

 

[jack]

I've lived with MVHR in a well insulated and airtight house in the South of England for 5 years. If I were building again, it would be the first thing in my list of essential things I'd include in a new house. If you haven't lived with the air quality, it's hard to explain.

 

I don't know where people get the idea that you can't open windows, but it seems very common. MVHR is at its best when it's very cold or very hot outside, which is when you probably don't want your windows open anyway (I mean, you can still open windows in that case, but you're going to make it less pleasant inside your house).

 

If you have lots of glass, you really want to think hard about how you're going to keep the house cool. MVHR will help a bit, but really you need to find a way to reduce solar gain, and possibly to cool the house with aircon or the like.

[Iceverge]

Great thread here that'll answer your questions.

 

https//forum.buildhub.org.uk/topic/12676-mvhr-is-largely-bogus/

[Bored Shopper]

I'm very pleased with our MVHR. We live near Heathrow, so quality of air is an issue at times. So far I can feel the pleasant difference, as we definitely have less respiratory problems. Unpleasant odours are sucked out quite efficiently from wet areas / kitchen, and I do enjoy very even temperature spread across the house. Expensive, yes, but I strongly believe every newbulid should have one.

[nod]

22 minutes ago, Bored Shopper said:

I'm very pleased with our MVHR. We live near Heathrow, so quality of air is an issue at times. So far I can feel the pleasant difference, as we definitely have less respiratory problems. Unpleasant odours are sucked out quite efficiently from wet areas / kitchen, and I do enjoy very even temperature spread across the house. Expensive, yes, but I strongly believe every newbulid should have one.

I was all set to include MVR

Ib our first build and a friend stated the opposite to you 

Whenever his neighbor burnt leaves (most days)

His MVR drew the smell in 

A regular poster JH stated the same about a chimney near him 

Which put my wife off 

My view would be like closing a window 

You can always switch the MVR 

Personally While I’ll never see the point of PV I would sooner use the money on MVR 

Though I would make sure the design of the house is suitable 

Jack makes a good point about glass 

The friends we visited yesterday that are having MVR problems Live in a very exposed place With lots of full height glazing 

So may be barking up the wrong tree trying to fix The MVR 

[Oz07]

Two minds really. I think the investment means you justify the benefits in your head. I like the idea of it but I don't really notice super fresh air like other people mention. Perhaps if I had a night back in a standard new build I would realise. I do think they increase your heating requirements slightly. 

[andy]

MVHR (and PV IMO) are both no brainers if you are building a modern, well insulated and airtight house.

 

I have a Zehnder Q350 unit and I can't speak highly enough of the unit - quiet, efficient and does what it says on the tin.

 

Given your other choice is *shudder* trickle vents - I mean, come on!!!!

[jack]

43 minutes ago, Oz07 said:

I do think they increase your heating requirements slightly. 

 

That surprises me. Is that based on your own experience?

[joe90]

52 minutes ago, Oz07 said:

I do think they increase your heating requirements slightly. 

I also am surprised at that, it’s got to be more efficient than an open window or trickle vent lat let’s in cold air surely. As an aside, because we live in the middle of knowhere we tend to open doors and windows in summer so I switch mine off, only on in winter!

[Nickfromwales]

1 hour ago, Oz07 said:

Two minds really. I think the investment means you justify the benefits in your head. I like the idea of it but I don't really notice super fresh air like other people mention. Perhaps if I had a night back in a standard new build I would realise. I do think they increase your heating requirements slightly. 

MVHR....

 

Mechanical 

Ventilation

with

HEAT 

RECOVERY 

 

 

 

The other option is to allow infiltration, trickle vents, and forced extraction to suck all the heated air ( the air you’ve just paid to heat ) out to the clouds and never to be seen again.

 

Oh, and I would love to hear of anyone who’s house doesn’t let smoke in regardless of MVHR. The benefit of MVHR vs a house with natural infiltration / forced extraction is you can turn off your MVHR during the piss-you-off-neighbours leaf burning activity, but you’d have to go around physically closing all the trickle vents and blocking up the extractors to stop that in a regular home. 
 

No sale so far on the reasons for not fitting it sorry. 

[Nickfromwales]

@Haku

Please say now which thing drives these decisions.

Commetcial sense, or owner / occupants comfort? 
You’re on a forum for people striving to do best in what may well be their forever home, so if you need commercial balance for financial gain then it’s best to set out your station so you can be offered the best advice.   

Plenty on here who rent / renovate for profit so you’re not alone   

[Moonshine]

I am still on the fence about them, I co sidered them for a long time, then I ran out of space/budget on my build.

If I can find the space (can they go in a garage) and I find the £5k I would consider it.

I may put a post up asking for advice of where to fit it in my plans.

The build is by a busy road, and it's the fresh air without opening windows or vents and the noise which sell it for me.

Edited March 13, 2021 by Moonshine

[joe90]

7 minutes ago, Moonshine said:

The build is by a busy road,

Another good reason for MVHR. Perhaps I was lucky but I bought mine on Ebay for a couple of hundred, yes a punt but it worked. Once it’s installed you can always change out the unit for another, a bit like UFH, once the pipes are in it’s easy, very difficult to retrofit.

[Nickfromwales]

If it’s outside the heated envelope then the ducts need to be very well insulated and the transition through the airtight layer needs meticulous detailing.

Post your plans, you can get slimline / horizontal etc. Options are out there for adverse situations. 

[Haku]

1 hour ago, Nickfromwales said:

@Haku

Please say now which thing drives these decisions.

Commetcial sense, or owner / occupants comfort? 
You’re on a forum for people striving to do best in what may well be their forever home, so if you need commercial balance for financial gain then it’s best to set out your station so you can be offered the best advice.   

Plenty on here who rent / renovate for profit so you’re not alone   

That's a great question. These 4 houses are for commercial resale. I've retained the 5th plot for my house which will most likely include MHVR as the cost:benefit considerations aren't the same (I have hay fever so filters that require checking every 4-6 months in exchange for less pollen is totally acceptable to me personally). I don't believe Joe blogs has a clue what MHVR is when they are out house shopping so I'm just trying to work out if there is a noticeable benefit from those that have it. Saving £100 a year on heating isnt a selling point in my view if you have to call in an engineer to do annual maintenance. Its about 3-4k more expensive than having extractor fans and trickle vents so the question is does it really improve quality of living significantly and does it noticeably cool the house in summer when potentially I think the houses will be very warm. 

[Haku]

1 hour ago, Nickfromwales said:

If it’s outside the heated envelope then the ducts need to be very well insulated and the transition through the airtight layer needs meticulous detailing.

Post your plans, you can get slimline / horizontal etc. Options are out there for adverse situations. 

I'd been looking at the system Kingspan can supply as part of the frame build/supply/installation package (Rega Heat ventillation). I'm struggling to find a builder with Timber Frame experience so hadn't planned on installing it (simplicity is best) until I realised one of the potential frame suppliers could do this. My concern is about the buildings overheating. I understand this isnt aircon but if the system alone can keep the house to a comfortable temp in summer I'd be tempted to add it.

[Haku]

1 hour ago, Moonshine said:

I am still on the fence about them, I co sidered them for a long time, then I ran out of space/budget on my build.

If I can find the space (can they go in a garage) and I find the £5k I would consider it.

I may put a post up asking for advice of where to fit it in my plans.

The build is by a busy road, and it's the fresh air without opening windows or vents and the noise which sell it for me.

I'm on a country lane in a village so air quality is generally good with pollen the only real concern. 5K is quite a chunk of money isnt it! I have space to put the unit in the plant room or loft but right now I dont have PV panels and if I'm going to upgrade something that looks more obviously useful to run the ASHP....unless the MHVR is a necessity rather than luxury

[recoveringbuilder]

22 minutes ago, Haku said:

That's a great question. These 4 houses are for commercial resale. I've retained the 5th plot for my house which will most likely include MHVR as the cost:benefit considerations aren't the same (I have hay fever so filters that require checking every 4-6 months in exchange for less pollen is totally acceptable to me personally). I don't believe Joe blogs has a clue what MHVR is when they are out house shopping so I'm just trying to work out if there is a noticeable benefit from those that have it. Saving £100 a year on heating isnt a selling point in my view if you have to call in an engineer to do annual maintenance. Its about 3-4k more expensive than having extractor fans and trickle vents so the question is does it really improve quality of living significantly and does it noticeably cool the house in summer when potentially I think the houses will be very warm. 

I think you’re right about Joe Bloggs not having a clue about mvhr, I know someone in a house with it who doesn’t know how to use it, I think even ufh causes some people a problem, we sold our house with ufh nearly 5 years ago, was speaking to the new owner a few weeks ago and they have taken it out and put in radiators as they weren’t happy with the reaction time!

[Temp]

14 hours ago, jack said:

I've lived with MVHR in a well insulated and airtight house in the South of England for 5 years. If I were building again, it would be the first thing in my list of essential things I'd include in a new house. If you haven't lived with the air quality, it's hard to explain.

 

+1

 

It was very noticeably better when we moved into our self build with MVHR. The first night it was like waking up after a night in a tent. The effect does wear off as you get used to it but we notice it again when coming back from a holiday.

 

Our house is not air tight so I doubt it pays for itself in our case but i'd fit one again.

 

Its now 13 years old and I noticed the bearings sound a bit noisy when I changed the filter - so might be time to replace them soon.

 

Edited March 13, 2021 by Temp

[SteamyTea]

24 minutes ago, recoveringbuilder said:

think you’re right about Joe Bloggs not having a clue about mvhr,

Joe Bloggs does not understand Economy 7, so not going to understand MVHR and UFH.

 

 

 

[jack]

23 minutes ago, Haku said:

I'd been looking at the system Kingspan can supply as part of the frame build/supply/installation package (Rega Heat ventillation). I'm struggling to find a builder with Timber Frame experience so hadn't planned on installing it (simplicity is best) until I realised one of the potential frame suppliers could do this. My concern is about the buildings overheating. I understand this isnt aircon but if the system alone can keep the house to a comfortable temp in summer I'd be tempted to add it.

 

It'll have very little impact on overheating unless you install some sort of cooling coil (driven by an ASHP).

 

It does help slightly when it's very hot, by helping to maintain any temperature difference between inside and out. That can be useful if you're using aircon, in particular.

[Oz07]

3 hours ago, jack said:

 

That surprises me. Is that based on your own experience?

Yes albeit not apples with apples. Been in this place 1 winter and before that was in a place I built 2016 ish. Similar u values similar size except this one a bungalow. Last air score around 3 this place just above 1. This place has mvhr, old relied on passive ventilation. I think the heating bills are very similar. Deffo no massive drop here. 

 

3 hours ago, Nickfromwales said:

MVHR....

 

Mechanical 

Ventilation

with

HEAT 

RECOVERY 

 

 

 

The other option is to allow infiltration, trickle vents, and forced extraction to suck all the heated air ( the air you’ve just paid to heat ) out to the clouds and never to be seen again.

 

I'm not a Neanderthal I just about understand the concept. I think what you will find though is a lot of places which rely on passive ventilation, if they have a decent ish air score around 3 or 4 are probably under ventilated though. My old place used to have all the trickles open and small bedroom window open or on the latch, even in winter. My bills were not noticeably more. In any case if they recovered 100% heat then you wouldn't get people turning them down after building regs sign off!

 

For me in a forever home I'd have one, for a commercial development not a chance. House buyers rather you spend 500 on a nest system and they'd probably think it saves them more money too!

 

[Nickfromwales]

5 minutes ago, Oz07 said:

I’m not a Neanderthal

Keep an eye out. Sabre- toothed tiger seen loose in your area. Be on high alert  

 

Edited March 13, 2021 by Nickfromwales