# Mechanical Heat Recovery Ventilation experiences



## Birroc (18 Jan 2008)

Has anyone installed one of these MHRV systems in their new build ?

If so, can you comment on your experiences in terms of 
- cost
- complexity
- efficiency
- reliability
etc


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## sse (18 Jan 2008)

We have HRV in our block-built house.

Installed by Proair of Galway. Very professional and thorough job, highly recommended.

Cost was c. 8k, but we have two units due to the size of the house.

Been in constant operation since October, no issues so far.

Complexity? Turn it on and leave it. When you have a shower/bath press boost. That's it.

In terms of efficiency, our gas bill for Nov/Dec was €111 for heating and hot water for a 450m2 house (with a recess woodbox fire for point heat on occasion). This is less than for the equivalent period last year in a poorly-detailed 3bed estate semi a quarter the size so that shows the benefit of good insulation and detailing and MHRV.

SSE


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## Franm (18 Jan 2008)

Hi Birroc,
I DIY installed a unit from MTD-Solutions back in November in our 70's bungalow so not a new build. But here are my thoughts to date.

- I went for this unit mainly because it only consumes about 20w in normal state (it ramps up when showering etc) and the company were very DIY friendly.
- House is much drier now, no condensation on inside of windows in the morning or in the bathroom when showering. The general dampness that we used to experience when we moved in a few years ago has (so far) gone.
- One feels much fresher in the morning when waking up
- Spiders are no longer in evidence around the house (in case that's important)
- Feels strange not opening the windows anymore
- very happy drying clothes in UT now as moisture is extracted.
- One might miss the hum from the old extractor fans in bathrooms (we don't)
- In our installation a very slight hum can be heard in bed late at night from the air coming out of the vent, but I need to follow up on this as it may be something to do with the way I ran the ducting.
- Total cost came to just over 5.5K and that included all the insulated ducting, vents, clips, tape etc. I believe I could have got it installed for another 500euro not including making the 2 x 6" holes in the wall.
It's very easy to operate, just plug it in and it also came with a remote which enables you to select low, medium or high speeds should you need it from time to time. We leave ours on Auto.
- There is a small maintenance job that must be done from time to time and that is to vacuum the filters
- Initially I thought it was chilling our bedroom but a check with a thermometer showed that this was not the case.

 All in all I'm very pleased with the outcome so far.
I know some units allow you to add a little heat which seems like a good idea but I was determined to keep the power usage to a minimum.
That's all I can think of at the moment.

Rgds
Fran
ps I've no connection with this company


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## Birroc (21 Jan 2008)

Thanks All. Sounds good.

Does all the internal ducting and piping make it difficult to install ?
I am building a 2 storey and I will have hollowcore ceilings so I am wondering where all pipes will go?


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## Xsue (21 Jan 2008)

We have just built with hollowcore floor and the ducting is all in the ceiling - we put a suspended ceiling (100mm I think) the pipes are square-ish. We got ours from Proair too......not in the house yet but am preparing to be impressed!


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## Birroc (22 Jan 2008)

Xsue said:


> We have just built with hollowcore floor and the ducting is all in the ceiling - we put a suspended ceiling (100mm I think) the pipes are square-ish. We got ours from Proair too......not in the house yet but am preparing to be impressed!


 
You put the pipes in the ceiling of the 1st floor ? Where did you put the pipes for the ground floor ?


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## sas (22 Jan 2008)

Birroc said:


> You put the pipes in the ceiling of the 1st floor ? Where did you put the pipes for the ground floor ?


 
I think you miss understood the answer you got. You have to batten underneath the hollowcore in order to attach the groundfloor ceiling. You run the ducting in the cavity created. You of course have to leave enough of a cavity to suit the specific ducting size. Some companies use a box ducting which is about 2.5 inches deep i.e. a 3inch cavity would be plenty. 

Hope this helps.


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## Hen (12 Feb 2008)

What is the return on putting in a MHRV system? 5 to 8 thousand is a lot of money, what is the saving per year and for how many years before you are looking at paying for maintenance/repair/replacement?


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## sse (12 Feb 2008)

Hen

Difficult to say what the return is, you're right they are expensive.

However you must have ventilation and the only real alternatives are a) passive stack (no personal experience), b) trickle vents on the windows c) wall vents.

b) and c) are basically the same as having holes in your walls.

MHRV enables you to make your house airtight and very well insulated (as much as possible) and this is where you make savings - you only have to heat a house by the amount of heat you lose. They also provide vapour control for bathrooms etc. and, an unforeseen benefit we are very glad of now, mean that you're not plagued quite as much by flies!

Many high-spec. houses now are including HRV so there are also resale benefits to consider. I'd say these units will be fairly ubiquitous before long.

In terms of maintenance the units themselves aren't too stressed so they should be longlasting and you need to replace/clean filters but I'm not sure there's much else to do.

SSE


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## johnnyg (13 Feb 2008)

Was thinking of putting in the ducting now when i'm building and later on put in the unit itself when i can afford it or when it becomes more economical.

Can you buy the ducting from building providers or must you get it off the companies that supply these units and is it expensive ie euro/meter?


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## cma (13 Feb 2008)

johhnnyg,

the option of putting in the ducting and when you can afford it - 2/3 years ?? is a postively bad one. under the building regulations houses ate required to be permantly ventilated. we've all see duncan stuart in the adverts on tv - regarding blocked vents etc. lets say you install the ducting with no hrv unit, then you light the fire, say for instance a closed gas fire, if there is a leak in the flue you and your family could be enhaling deadly toxic fumes and not even realise it. 

my advice, put it in now. its far more effectve than any other forms of ventialtion. but don t do half now and half later


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## johnnyg (13 Feb 2008)

I will have ventilation in the form of trickle vents, unfortunatey our budget is stretched as we have gone with geo/UFH.


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## cma (13 Feb 2008)

weigh up the cost of adding trickle vents to your windows, versus installing the hrv, one company i've dealt wth [not involved in company]] are mtd-solutions.com, they have a hrv with 97% heat recovery. fair enough money is tight but you and your partner/wife will hopefullly only build a family home once. so perhaps cut back on the quality of the wallpaper items of the house, and put the money into the bones of the house now. perhaps don't finish out one of your bedrooms for a couple of years


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## sas (13 Feb 2008)

johnnyg said:


> I will have ventilation in the form of trickle vents, unfortunatey our budget is stretched as we have gone with geo/UFH.


 
How would you intend sealing those trickle vents down the line when you are ready to install the HRV unit? I've never seen a trickle vent that was anything close to airtight when closed.


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## johnnyg (13 Feb 2008)

the ones i have seen are airtight when closed, its only a thought as we hadn't planned to go with geo/ufh, we are taking the hit on that over HRV, so was thinking of putting in the ductwotk downstairs only just in case we ever go for it down the line...


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## pops (13 Feb 2008)

We also got ours from Pro-air and are very happy with it.  We were strapped for extra cash, but our geo-therm. guys recommended the MHRV as a way of making the whole system  more efficient.  No condensation is a great thing. Your house will be healthier overall.  If anyone in your house suffers from hay-fever, special filters can be fitted to prevent irritants coming in from outside.  And Franm is right about the spiders.  They're just not there.  Does anyone know why this is??


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## pops (13 Feb 2008)

We also got ours from Pro-air and are very happy with it.  We were strapped for extra cash, but our geo-therm. guys recommended the MHRV as a way of making the whole system  more efficient.  No condensation is a great thing. Your house will be healthier overall.  If anyone in your house suffers from hay-fever, special filters can be fitted to prevent irritants coming in from outside.  And Franm is right about the spiders.  They're just not there.  Does anyone know why this is??


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## Hen (13 Feb 2008)

For a house in the country that is only occupied at night during the week and at the weekends, is a MHRV system worth it? Spiders or slatters are not a concern, and the house is healthy even before damp proofing the floors.


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## Birroc (13 Feb 2008)

pops said:


> We also got ours from Pro-air and are very happy with it. We were strapped for extra cash, but our geo-therm. guys recommended the MHRV as a way of making the whole system more efficient. No condensation is a great thing. Your house will be healthier overall. If anyone in your house suffers from hay-fever, special filters can be fitted to prevent irritants coming in from outside. And Franm is right about the spiders. They're just not there. Does anyone know why this is??


 
2 questions;

Is it noisy in any way? 

Did anyone hear of this air tight membrane that should also be fitted on all outside walls to ensure air tightness and thus increase MHRV efficiency ?


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## sas (13 Feb 2008)

Birroc said:


> Did anyone hear of this air tight membrane that should also be fitted on all outside walls to ensure air tightness and thus increase MHRV efficiency ?


 
It's mostly only used in timberframe houses to make them airtight. A plastered block wall is airtight as long as you plaster right down to the floor. You will need specialist airtightness tapes around the windows\doors etc. 

www.ecologicalbuildingsystems.com supply the Proclima Intello system.

They also give very good (and free) advice on how to make any build type airtight.


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## sas (13 Feb 2008)

Birroc said:


> Is it noisy in any way?


 
It shouldn't be. 

The best piece of advice I got was to not position outlets over beds as I've heard people complain that they can feel the (albeit slight) breeze on themselves at night!

Also, steer clear of any system that uses flexible currugated piping. Even common sense would suggest that the smoother the path for the air flow, the more efficiently the system can run.


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## pops (14 Feb 2008)

Re noise, it does hum a bit when it's on boost and if you have a particularly quiet house you would hear that.  It's a struggle to hear oneself think in ours though, so that's not a problem.  The guys recommended that we position the fresh-air vents near the bottom of the bed so that there wasn't a breeze coming in at night but I have never noticed it. We have a block-built house so no need for the membrane.


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## NiallA (14 Feb 2008)

pops said:


> And Franm is right about the spiders.  They're just not there.  Does anyone know why this is??



Supposedly as there is less moisture in the air dust mites cannot survive, and these are the main food source of house spiders.

I have installed a system from MTD -Solutions in a 1970s two storey house, ducting a bit awkward fro downstairs, (ran ducts down behind built in wardrobe and then between joists in first floor.

i had noticed quite a bit of noise at night (our bedroom is the closest to the unit) and have fitted a timeclock to turn off the fans at night and on again in the morning.

other than that no problem.

don't have it long enough to know how much it is saving (if anything)

biggest problem is making old house airtight.


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## Birroc (16 Feb 2008)

How much electricity do MHRV systems use in a year ?

Is there any problem turning them off completely e.g. when you have the windows open in summer ?


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## mudhut (28 Feb 2008)

I am currently considering building the kingspan tek Sip House, which they recommend MHRV systems, they even suggest that in Sip homes it can be your primary heat source (no rads) when hooked up to a boiler, I am having their engineers look at my plans to see if the system would be adequate, will also have my engineer do the same.
the system they use is Nuaire Eco scrubo, which will be dropped to site only with all accessories for E 12,435 excluding vat, this seems a little excesive to me and may be worth my while to shop around, i will check out ProAir as mentioned here , but if anybody knows any other suppliers fitters based in around the border counties I would appreciate the info 

cheers to all

MudHut


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## zander (28 Feb 2008)

Hope its ok to tag onto the post.
Is it possible to have gas or wood pellet/chip fires in a house that has a HRV system installed.  We are planning to have a solid fuel stove in one room and have two other fireplaces in the house and not sure what we can use in these.
Thanks


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## lastbuilders (29 Feb 2008)

We have a multifuel stove in our house with a HRV system and it works grand. You should make sure the HRV is turned on when the stove is running though to feed the stove. 

Lastbuilders


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## endag. (29 Feb 2008)

some stoves allow for an independant air intake of air from outside the house. one idea mght be to put a wavin pipe in the foundations if you havent started them already.
i think that there is no Cassettte fire which has this option available.

there is a company in Belfast that supply systems. not sure if they install, i have no connection apart from seeing them at one of the shows and that i wil prob go with them,. i liked their approach: on their web site you can calculate the price from a table, no smoke and mirrors, which i think are in abundance inteh south of ireland... and the price, taking into account the vat i think that i am still getting a good deal, for supply only:  €3642, excluding delvery as i will be able to collect it. maybe i am naieve but instillation shouldnt be too crazy hard, especially if the suppliers provide adequate plans. its just a box with pipes, ill get the electrician to connect it up, and will have plenty of money to spare.
the company is called Brookvent, web site is brookvent.co.uk


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## bakerbhoy (29 Feb 2008)

endag. said:


> some stoves allow for an independant air intake of air from outside the house. one idea mght be to put a wavin pipe in the foundations if you havent started them already.
> i think that there is no Cassettte fire which has this option available.
> 
> 
> ...


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## Guju121 (2 Mar 2008)

Got a quote of 6.5k for MTD-solution for a 260m2 bunglow, €4600 for the unit itself and the rest was ducting etc. Seems expensive to me. Anyone know of other suppliers which might me cheaper. What kit of price is the system from Pro-air.


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## cowboy (2 Mar 2008)

my quote from them was closer to 8000 for 279 sqm dormer. Would be interested in other companies too. Saying that the MTD one seems to have a very high heat recovery percentage


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## endag. (3 Mar 2008)

thanks baberbhoy. 

for hrv try brookvent.co.uk, office in Belfast,no affiliation to me...


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## sas (3 Mar 2008)

cowboy said:


> my quote from them was closer to 8000 for 279 sqm dormer. Would be interested in other companies too. Saying that the MTD one seems to have a very high heat recovery percentage


 
Ask MTD what independant body tested their unit and will stand over their performance figures.


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## Guju121 (4 Mar 2008)

Checked out the Brookvent place. Price was good but they use flexable hose ( bad for efficient air flow ) and not sure if it is insulated or not. 20% extra ( 20% of the whole system price ) if you want rigit hose. This makes a big difference to the price.


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## gally74 (21 Mar 2008)

hello,

i have looked at a lot of systems and am now considering a DIY approach to this, units seem to be aroun 400-1000 dollars, plus ducting controls etc. way cheaper than 4-8K


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## luap_42 (10 Sep 2008)

Guju121 said:


> Got a quote of 6.5k for MTD-solution for a 260m2 bunglow, €4600 for the unit itself and the rest was ducting etc. Seems expensive to me. Anyone know of other suppliers which might me cheaper. What kit of price is the system from Pro-air.


 
I got a Proair system into a 115m2 semi-D last year for £3800 all up including three booster switches, even though it was after first fix. I've been advised that two smaller units are more efficient (and cheaper) than one large one. Seem to remember the unit alone costing about €1800.


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## endag. (12 Sep 2008)

have just seen what is delivered in the first fix of both Brook Vent and MTD. ducuting is same: flexible insulated and non insulated, with very similar solid joints, and same valves. different way of fastening all right but the difference in price is thousands of euro>>>> i am not affilliated with brookvent, but hate to see southerners pay over the odds for materials available a drive away!!!


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## krissovo (12 Sep 2008)

cowboy said:


> my quote from them was closer to 8000 for 279 sqm dormer. Would be interested in other companies too. Saying that the MTD one seems to have a very high heat recovery percentage



Snap, they did go down to €7.5k but I am sure there is more to be gained.  7.5k is a lot for a big air pump.


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## rmdt (12 Sep 2008)

I was very impressed when I saw the MTD system at the self build show, the quote was pretty scary alright though...€8000 for a 2900sq ft bungalow!  Came down to €7500 straight away though and think there is more scope there!

One question I have is that MTD recommend flexible ducting that looks like tinfoil (but is amazingly strong, and the way it deadens sound is impressive), while many others say that flexible is a disaster.  Is one better than the other or do they both have there pro's and con's?

Also, is it worth paying them €500-600 euro to install, I am pretty good at diy, and apart from complicated wiring and plumbing would chance just about anything...except plastering!


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## papaC (28 Oct 2008)

Hi all. I have done my own Diy pipework for mhrv in a complete rebuid of a ruined 150 sq m farmhouse. I just read up on it and used wavin pipe which I collected from skips and site dumps. It has cost about ten euros so far and I think it will work as well as the mega expensive jobs. (The build has taken a few years so I had plenty of time for the scavenging and figuring out). 

Its not the rocket science the professionals would have you believe it is. I was on a site where a 10k mhrv system was being installed. I spoke to the installer and it took thirty seconds to figure out that he knew nothing about it.!!!! Caveat Emptor!!!

I am looking into the units now and would appreciate any recommendations for cheap reliable ones. Cheers.


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## Towger (29 Oct 2008)

Just incase anyone is interest. Kingspan are flogging off their own brand units on ebay at the moment : http://shop.ebay.ie/merchant/kingspancentury


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## alexjames (23 Mar 2009)

hi all new to the forum. i was just wondering about the MHRV, i am going to start my house in the next few weeks which is a storey and a half and was wondering two things 1) What type of floor construction do you need ie. can it be used with timber joists? 2) do i need a heat source ie. central heating. thank you in advance for your help!


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