MHRV and ventilation

Curious Geroge

The time is ccomingon decision around ventilation. HRV is the buzz word at the moment but since the heat source is a heat pump with underfloor throughout, full airtightness planned, heat recovery means little but I am concerned about good ventilation. Can someone help me list all the options. Hole in the wall is out as what's the point of airtightness if I do this but I have heard lads talking about controlled hole in wall setups for ventilation but no names.

kilclon

Why does heat recovery mean little? All it does is mechanically extract warm air from the building while transferring the heat to the fresh air which is pumped into the building. The controlled hole in the wall setup you are talking about may be some form of demand controlled ventilation.

Curious Geroge

kilclon wrote: »

Why does heat recovery mean little? All it does is mechanically extract warm air from the building while transferring the heat to the fresh air which is pumped into the building. The controlled hole in the wall setup you are talking about may be some form of demand controlled ventilation.

This may be my confusion but is HRV not heat recovery, as in moving heat around the house while also providing ventilation. Since the heat pump is generating heat for the whole house at a constant, moving heat wouldn't apply thus ventilation is the only requirement.

The demand controlled ventilation is something I've onlly just learnt about so I'm more than concerned that there may be many other options I'm not aware of yet and hoped those that are in the same position now or those that have this done may share there thoughts/setups so I can review and compare *all* available options to me.

BryanF

Curious Geroge wrote: »

This may be my confusion but is HRV not heat recovery,

yes

as in moving heat around the house while also providing ventilation.

a certain amount yes

Since the heat pump is generating heat for the whole house at a constant, moving heat wouldn't apply thus ventilation is the only requirement.

so you dont want to recycle the heat generated, and your happy to just vent it out and reheat the newly vented cold air[/QUOTE]

The demand controlled ventilation is something I've only just learnt about so I'm more than concerned that there may be many other options I'm not aware of yet and hoped those that are in the same position now or those that have this done may share there thoughts/setups so I can review and compare *all* available options to me.[/QUOTE]
MVHR mechanical ventilation heat recovery (or 'HRV' heat recovery ventilation). MVHR is a central whole house system that through a heat exchanger can recycle upto say 80% of the heat that would otherwise be lost. it is the most efficient/low Co2 option for ventilation in a modern build: the 'cons' are its expensive to install, its specification is paramount, and all maintenance matters need to be considered early in the design and selection of the unit.
MEV mechanical extract ventilation is a centralised extract with humidity controls. the theory is extract points in kitchen & wc's extract more air than is provide in to those rooms, thereby drawing air in from whole in the wall vents in each of the rooms. these vents in each habitable room have a control system on them. cons you will be heating more air than the MVHR system. pros cheaper at approx half the MVHR price and suitable for retro-fits where AT cant be achieved.

after that you've got hole in the wall & trickle vents neither of which are ideal as we strive for lower Co2 running costs in buildings.

Curious Geroge

BryanF wrote: »

MVHR mechanical ventilation heat recovery (or 'HRV' heat recovery ventilation). MVHR is a central whole house system that through a heat exchanger can recycle upto say 80% of the heat that would otherwise be lost. it is the most efficient/low Co2 option for ventilation in a modern build: the 'cons' are its expensive to install, its specification is paramount, and all maintenance matters need to be considered early in the design and selection of the unit.
MEV mechanical extract ventilation is a centralised extract with humidity controls. the theory is extract points in kitchen & wc's extract more air than is provide in to those rooms, thereby drawing air in from whole in the wall vents in each of the rooms. these vents in each habitable room have a control system on them. cons you will be heating more air than the MVHR system. pros cheaper at approx half the MVHR price and suitable for retro-fits where AT cant be achieved.

Thanks for the information. Its more of less what I had thought but not fully understood (not for my lack of trying but the fact that each and every installer to date has a difference approach in selling it, leading to totally confusion)

If MVHR is moving the air around the house - now I doubt its moving heat or whats the point of a zoned heating or whats the point of the heat pump (I would expect this to run as set and the fact that its airtight help achieve this).To circulate fresh air into the house MVHR would have to dump %'s of hot air, but not 100% as MEV would. BUT am I correct that MEV would not be running anywhere near the same % of time but the overall % of dumped "generated heat" would not be a large differential ? (maybe its down to the system and its design). Also, MEV does'nt seem to have ducting so I've no concerns over dust and bacteria resting in the ducts leading to unknowns in the future (a con introducted by another sales pitch when trying to sell PVC ducting over metal - made no sense as he was diss'ing both in my mind).

But I seem to have the options down, MHVR, MEV, trickle vents.. nothing else out there..

kilclon

You could look at a decentralized mvhr system. Look up lunos for example.

Curious Geroge

kilclon wrote: »

You could look at a decentralized mvhr system. Look up lunos for example.

Thanks. Looking at lunos and aereco on MEV while looking at paul and brink on mhrv.

Also came across this explanation which helps but everyone has an opinion on this.

<<<George try to find one thats not from a product supplier. thanks >>>

Old Jim

Curious Geroge wrote: »

But I seem to have the options down, MHVR, MEV, trickle vents.. nothing else out there..

One other option is the Breathing Window. No ducts to get dirty. Sounds good in theory and should be cheaper than a ducted system but have not heard much real-life feedback. Google for more information.

BryanF

Old Jim wrote: »

One other option is the Breathing Window. No ducts to get dirty. Sounds good in theory and should be cheaper than a ducted system but have not heard much real-life feedback.

show us the certification for this? CE or IAB/ BBA

Google for more information.

don't waste your time until the above is provided

joeirish

Curious Geroge wrote: »

Thanks. Looking at lunos and aereco on MEV while looking at paul and brink on mhrv.

Also came across this explanation which helps but everyone has an opinion on this.

<<<George try to find one thats not from a product supplier. thanks >>>

George

I've PM'd you asking for your explanation. I too am looking at some of these systems.

hexosan

Old Jim wrote: »

One other option is the Breathing Window. No ducts to get dirty. Sounds good in theory and should be cheaper than a ducted system but have not heard much real-life feedback. Google for more information.

When you say breathing window do you mean from a certain Nordic house company

joeirish

hexosan wrote: »

When you say breathing window do you mean from a certain Nordic house company

The previously mentioned company L*******s show them on done of their websites also, Australia or USA I think.

BryanF

joeirish wrote: »

The previously mentioned company L*******s show them on done of their websites also, Australia or USA I think.

Why waste your time if there not EC certified ?