Heat Recovery

mtgalway2014 · 29-09-2014 11:10pm #1

Any one out there have a Dimplex QV400 Heat Recovery System ?
Just wondering how it operates - thinking of installing one?
Has been recommended to me ?
I have a 4 bedroom bungalow so install should be ok.

BryanF · 29-09-2014 11:43pm

Can you divulge the Air-tightness test results for your house?

mtgalway2014 · 01-10-2014 8:16pm

I haven't had an air tightness test done. Should I?
8 year old house double glazing , attic insulated , floors insulated , cavity pumped.

MicktheMan · 01-10-2014 9:42pm

mtgalway2014 wrote: »

I haven't had an air tightness test done. Should I?
8 year old house double glazing , attic insulated , floors insulated , cavity pumped.

You should (the hr part of mvhr is pointless above a certain leakage rate).
Btw, why are you considering it?

damianmc · 03-10-2014 11:28am

General question about HRV, how do you heat your hot water if there is no other heating source?

BryanF · 03-10-2014 11:30am

mtgalway2014 wrote: »

Any one out there have a Dimplex QV400 Heat Recovery System ?
Just wondering how it operates - thinking of installing one?
Has been recommended to me ?
I have a 4 bedroom bungalow so install should be ok.

mtgalway2014 wrote: »

I haven't had an air tightness test done Should I?
8 year old house double glazing , attic insulated , floors insulated , cavity pumped.

forget it..

BryanF · 03-10-2014 11:32am

damianmc wrote: »

General question about HRV, how do you heat your hot water if there is no other heating source?

you do have a heating source

damianmc · 03-10-2014 11:36am

BryanF wrote: »

you do have a heating source

such as?

BryanF · 03-10-2014 12:00pm

damianmc wrote: »

such as?

Oil /gas /wood boiler or ground/air source heat pump or solar panels etc

damianmc · 03-10-2014 12:32pm

BryanF wrote: »

Oil /gas /wood boiler or ground/air source heat pump or solar panels etc

it would sort of defeat the purpose of putting in a HR system if you going to put in a standard heating system alongside it.
I was hoping to put in HR witha a small woodburneing stove, but im not sure of the best way to provide conveinient hot water.

murphaph · 04-10-2014 1:42pm

damianmc wrote: »

it would sort of defeat the purpose of putting in a HR system if you going to put in a standard heating system alongside it.

Why? The heating system chosen is more or less irrelevant to MHRV...the aim is to suck used stale air from the building and replace it with fresh air from outside BUT passing the stale air through a heat exchanger to extract as much energy as possible from it before venting almost cold air to the outside world.

How you initially heat that stale air is not a concern of the MHRV system. The heating system, be it oil, gas or heat pump will simply have to work less if you have MHRV (in a suitably air tight building) as the building will be leaking far less energy than otherwise.

mtgalway2014 · 04-10-2014 3:59pm

Does anyone know why there would be lots of condensation on the inside of the windows in the mornings?

BryanF · 04-10-2014 4:04pm

mtgalway2014 wrote: »

Does anyone know why there would be lots of condensation on the inside of the windows in the mornings?

The windows are probably the Coldest surface you have in the room. You create moisture, it condenses on the window. It's a sign you do not have adequate ventilation

mtgalway2014 · 04-10-2014 4:07pm

Would a MHRV system then be an advantage or waste of time?

BryanF · 04-10-2014 5:00pm

mtgalway2014 wrote: »

Would a MHRV system then be an advantage or waste of time?

Answered already.
Mvhr systems are suitable for new builds or extensively air-tight retro-fits. From what you have stated perhaps check out demand control mechanical ventilation.

BryanF · 04-10-2014 6:34pm

damianmc wrote: »

it would sort of defeat the purpose of putting in a HR system if you going to put in a standard heating system alongside it.
I was hoping to put in HR witha a small woodburneing stove, but im not sure of the best way to provide conveinient hot water.

Have you gotten provisional BER carried out?

mtgalway2014 · 04-10-2014 10:08pm

Thanks Brian

MicktheMan · 04-10-2014 10:54pm

mtgalway2014 wrote: »

Does anyone know why there would be lots of condensation on the inside of the windows in the mornings?

Yes:) ...

Take your pick:

1. this condensation appears for a short period of time at the start of the heating season and then reduces significantly quite quickly as the colder weather continues. This is normal and means that your house is drying out after the summer and is adequately ventilated.

2. this condensation appears at the start of the heating season and does not reduce but, rather, it continues for the duration of the heating season. This is not normal in an adequately heated and ventilated house.

damianmc · 06-10-2014 10:32am

BryanF wrote: »

Have you gotten provisional BER carried out?

Im only at the stage of planninga new build and was considering what heating system to put in, i like teh sound of the HRV systems and would also like a small stove in the main living space, but not sure how you would heat hot water then?
Maybe just electric showers?

BryanF · 06-10-2014 10:37am

damianmc wrote: »

Im only at the stage of planninga new build and was considering what heating system to put in, i like teh sound of the HRV systems and would also like a small stove in the main living space, but not sure how you would heat hot water then?
Maybe just electric showers?

I think it's best if you start detailed design of your house and get a BER done, you will then have a better idea of what is required to meet the current regs.

damianmc · 06-10-2014 11:09am

BryanF wrote: »

I think it's best if you start detailed design of your house and get a BER done, you will then have a better idea of what is required to meet the current regs.

im in the north so the new regs wont really apply, its justa low energy heating system im after, but i like the other benefits of the better air quality of the HRV system aswell.

MicktheMan · 06-10-2014 9:06pm

damianmc wrote: »

im in the north so the new regs wont really apply, its justa low energy heating system im after, but i like the other benefits of the better air quality of the HRV system aswell.

You do know, don't you, that a mvhr system is a ventilation system and not a heating system?

damianmc · 07-10-2014 9:27am

MicktheMan wrote: »

You do know, don't you, that a mvhr system is a ventilation system and not a heating system?

Yeah, but obviously when installed in an air tight house, it takes very little to heat the whole house andI would like to use something like a small wood brning stove for that.
What i am asking is, what is the best method then to provide hot water for showers etc?
Are solar panels any use for this or would you be best with just electric showers?

BryanF · 07-10-2014 11:04am

damianmc wrote: »

Yeah, but obviously when installed in an air tight house, it takes very little to heat the whole house andI would like to use something like a small wood brning stove for that.
What i am asking is, what is the best method then to provide hot water for showers etc?
Are solar panels any use for this or would you be best with just electric showers?

compliance with building regs part L may limit your options (that's why I asked about your provisional BER). Have you considered a log boiler with large hw tank, at least that way you may not have to spark a stove everyday.

MENACE2010 · 09-10-2014 3:13pm

mtgalway2014 wrote: »

Does anyone know why there would be lots of condensation on the inside of the windows in the mornings?

Lack of ventilation. This happens normally with single pane glass...if this is double glass humidity is high with poor ventilatin

stuckintipp · 28-12-2014 12:45am

Hi,

I'm getting close to the stage on our house build where final decisions need to be a number of the plumbing sections.

I like the sound of MVHR but plumber doesn't rate it? Any thoughts?

Also plumber reckons it wouldnt work In our place as we will have a gas wall mounted stove in main open plan living area & kitchen area along with a solid fuel stove In sitting room. I'm informed these rooms need a continuous fresh air supply thereby making MVHR obsolete. Would plumber be correct?

Builder has suggested that vent for gas stove can be put behind it onto outside wall and have it sealed off from room while sitting room can be ignored from rest of building with good door insulation?

Thanks in advance.

BryanF · 28-12-2014 1:12pm

stuckintipp wrote: »

Hi,

I'm getting close to the stage on our house build where final decisions need to be a number of the plumbing sections.

I like the sound of MVHR but plumber doesn't rate it? Any thoughts?

Also plumber reckons it wouldnt work In our place as we will have a gas wall mounted stove in main open plan living area & kitchen area along with a solid fuel stove In sitting room. I'm informed these rooms need a continuous fresh air supply thereby making MVHR obsolete. Would plumber be correct?

Builder has suggested that vent for gas stove can be put behind it onto outside wall and have it sealed off from room while sitting room can be ignored from rest of building with good door insulation?

Thanks in advance.

That's the first time I've heard of a plumber dictating a ventilation system.
You should have considered the Mvhr BEFORE you selected the gas fire & stove.
Your plumber is correct, that you require 'room sealed stoves with 'external air supply'.
You may/probably will find that neither of your selected appliances are room sealed.

1. The real question is when did decide that you wanted MVHR? Was it before Gas & stove were selected/installed?
2. And have you carried out an air-rightness test? What is the result?

The builder may be correct to suggest an external air supply, but to ignore the sitting room is dangerous - every room requires proper ventilation.

3. You have not mentioned an architect or M&E engineer - who is advising you?
4. Are your plumber and builder qualified to advise and certify compliance with building Regs on ventilation et al?

murphy31ie · 21-02-2015 3:32am

Hi BryanF,
I am putting in GSHP, ufh throughout, insulating well and making airtight as possible so using HRV. No chimneys in the house but the misses wants a focal point/flame in the mail living area. We have looked at a three sided glass gas fire, it is vented with a balance flue and is fully sealed. Any thoughts or concerns that the gas fire could cause issues with the airtighness. Any advice negative or positive is welcomed.
Thanks
2500sq foot new build

BryanF · 21-02-2015 6:34pm

you've asked this question elsewhere, once is enough thanks

galwaytt · 25-02-2015 2:56pm

stuckintipp wrote: »

Hi,

I'm getting close to the stage on our house build where final decisions need to be a number of the plumbing sections.

I like the sound of MVHR but plumber doesn't rate it? Any thoughts?

Also plumber reckons it wouldnt work In our place as we will have a gas wall mounted stove in main open plan living area & kitchen area along with a solid fuel stove In sitting room. I'm informed these rooms need a continuous fresh air supply thereby making MVHR obsolete. Would plumber be correct?

Builder has suggested that vent for gas stove can be put behind it onto outside wall and have it sealed off from room while sitting room can be ignored from rest of building with good door insulation?

Thanks in advance.

why on earth are you listening to a plumber about MHRV and ventilation ?

murphaph · 26-02-2015 1:41pm

We were quoted 23k (supply and fit) for a Zehnder Comfo Air system (MHRV) by our prefab house builder here. They quoted just €790 for machanical ventilation without heat recovery. I was absolutely gobsmacked by the price difference...sure the central unit is a couple of grand more expensive and the Zehnder requires more ducting (fresh supply to the room, whereas the system without heat recovery pulls the fresh air in (untempered) through wall vents (due to the slight vacuum created by the dirty warm air from kitchen and bathrooms being pumped out). I can't wrap my head around the huge difference though.

Can't justify 23k whatsoever...gonna take the system without heat recovery.

Condenser · 26-02-2015 2:52pm

murphaph wrote: »

We were quoted 23k (supply and fit) for a Zehnder Comfo Air system (MHRV) by our prefab house builder here. They quoted just €790 for machanical ventilation without heat recovery. I was absolutely gobsmacked by the price difference...sure the central unit is a couple of grand more expensive and the Zehnder requires more ducting (fresh supply to the room, whereas the system without heat recovery pulls the fresh air in (untempered) through wall vents (due to the slight vacuum created by the dirty warm air from kitchen and bathrooms being pumped out). I can't wrap my head around the huge difference though.

Can't justify 23k whatsoever...gonna take the system without heat recovery.

Why not just get another quote? The system shouldn't cost any more than €5-7K depending on house size

murphaph · 26-02-2015 3:45pm

We're building a house with a company that does everything, so we have peace of mind should a particular item not work, a single company is liable, no matter what the problem is. The ducting (and loads of other stuff) gets entombed in the floor screed over the UFH, so if the MHRV guy messes up and the floor needs to be lifted, it would be a legal minefield as to who is responsible for the ancillary works....we want to exclude that risk. It obviously limits us more than if we did things differently, but the base price of the house (IMO) cannot be beaten, so we accept these restrictions. It's the only thing where we have said "that would be better if we weren't tied to the builder's solutions". Otherwise it's all been ok. We will install Photovoltaic through a third party, but that's ok as it in more or less stand alone (the house builder will include a service shaft up through the centre of the house to allow for such things to be added later).

In fairness it would be decent sized job as we are building with a cellar and the ducting all has to go back to the utility room down there and they'd have to price for more breakthroughs through the reinforced concrete cellar roof and walls. It is a "nice markup" though I reckon.

Condenser · 26-02-2015 4:52pm

murphaph wrote: »

We're building a house with a company that does everything, so we have peace of mind should a particular item not work, a single company is liable, no matter what the problem is. The ducting (and loads of other stuff) gets entombed in the floor screed over the UFH, so if the MHRV guy messes up and the floor needs to be lifted, it would be a legal minefield as to who is responsible for the ancillary works....we want to exclude that risk. It obviously limits us more than if we did things differently, but the base price of the house (IMO) cannot be beaten, so we accept these restrictions. It's the only thing where we have said "that would be better if we weren't tied to the builder's solutions". Otherwise it's all been ok. We will install Photovoltaic through a third party, but that's ok as it in more or less stand alone (the house builder will include a service shaft up through the centre of the house to allow for such things to be added later).

In fairness it would be decent sized job as we are building with a cellar and the ducting all has to go back to the utility room down there and they'd have to price for more breakthroughs through the reinforced concrete cellar roof and walls. It is a "nice markup" though I reckon.

€15k for a bit of core drilling. Nice work if you can get it

ferryman35 · 26-02-2015 5:03pm

2 things strike me from your post -

- that price is way too expensive. I have a very decent spec'd system bought for about 1/3rd of your quotation, and even that could be leaning towards the expensive side.....

- you also mention that the ducting is in the floorscreed above the ufh.....I hope you meant beneath it??

murphaph · 26-02-2015 6:57pm

Yes, ducting and other services at the bottom, then UFH then screed.

@Condenser...agreed it's a huge markup on that item, which is indeed hard to fathom as the system we will take (this one) will still mean core drilling through the cellar roof/ground floor and it is literally a fraction of the price of the Zehnder Comfo Air. I can't fault them on the other stuff though so don't want to be too hard on them. They are coming in way under similar type houses and they include a blower door test as standard (carried out independently) and you don't have to pay anything until the house is snagged and accepted.

rampantbunny · 11-03-2015 1:08pm

murphaph wrote: »

Yes, ducting and other services at the bottom, then UFH then screed.

@Condenser...agreed it's a huge markup on that item, which is indeed hard to fathom as the system we will take (this one) will still mean core drilling through the cellar roof/ground floor and it is literally a fraction of the price of the Zehnder Comfo Air. I can't fault them on the other stuff though so don't want to be too hard on them. They are coming in way under similar type houses and they include a blower door test as standard (carried out independently) and you don't have to pay anything until the house is snagged and accepted.

Zehnder are considered by some as a better than average product but that price appears outlandish (saying this without having seen the complexity of your installs).
If your duct runs are long/complex, there's always the option of installing two units to service the house. Some on here have taken that approach for one reason or another and for cheaper than your quote I think.
The fact that the company have been good about everything up to now is not a reason for you to concede. It's your house, you get what you want. Losing the heat recovery aspect would be a major no IMO.

TSQ · 01-03-2016 1:53pm

Am renovating a small terraced house, completely gutting it and it will be well insulated when finished.

I have been quoted thousands by Gas Networks Ireland to connect to the gas mains (even though it is only yards from my front door) so now I am thinking of installing mechanical ventilation with heat recovery, and dispensing with central heating. What is the general opinion out there?

There is an open plan living/kitchen downstairs, with open plan staircase, 2 bedrooms and a bathroom upstairs, no attic to speak of, total floor area of house is under 700 square feet.

I am wondering if a fully ducted system in conjunction with a small solid fuel stove in the open-plan downstairs living/kitchen area would be sufficient to heat the house in winter? I would have to locate the MHRV unit outside, in the yard, as no room in attic or elsewhere.

Also, any suggestions re. hot water heating? am not in a position to install solar.

Lots of posts on MHRV, but haven't seen anything that answers this particular question.

MENACE2010 · 01-03-2016 2:21pm

TSQ wrote: »

Am renovating a small terraced house, completely gutting it and it will be well insulated when finished.

I have been quoted thousands by Gas Networks Ireland to connect to the gas mains (even though it is only yards from my front door) so now I am thinking of installing mechanical ventilation with heat recovery, and dispensing with central heating. What is the general opinion out there?

There is an open plan living/kitchen downstairs, with open plan staircase, 2 bedrooms and a bathroom upstairs, no attic to speak of, total floor area of house is under 700 square feet.

I am wondering if a fully ducted system in conjunction with a small solid fuel stove in the open-plan downstairs living/kitchen area would be sufficient to heat the house in winter? I would have to locate the MHRV unit outside, in the yard, as no room in attic or elsewhere.

Also, any suggestions re. hot water heating? am not in a position to install solar.

Lots of posts on MHRV, but haven't seen anything that answers this particular question.

Hi
okay first things first MHRV is not a heat source.. lets get that out of the way quick , its in the name it "recovers" heat , its also not a heat distribution method that "distribute heat" through the house.

MHRV is a method to ventilate your "airtight" house with fresh air without losing oodles of energy. it will extract from kitchen and bathroom area's, typically , and exchange that air "temperature" via a membrane coming into the house via the same ventilation equipment without "touching" each other. This is excellent in the winter months , in the summer just open a window

So well insulated to what ? from the size description its not a massive abode .. so I would "advise" to consider triple glazing in windows, insulated plaster board and try to make it "draft proof" as airtight will be some challenge in older houses.

Having done that you minimize heat loss, again people on this board and others expecting some "silver bullet " solution but there is none really as every house is different ( orientation / location will have a massive effect on the performance and heat loss).

So the next step is to establish your heating "need" after your insulation project ,there are tools on the internet but I would suggest to get in touch with a professional who has experience and can assist. ( PM me for a recommendation) .

Then you can select your heat source , a small stove would need firing every day don't forget that unless you specify the stove correctly , it will need to be fired regularly ( we have a 5KW stove and that heats the ground floor with ease but we fire it only when its really cold outside for some instant heat, Air source heatpump with UFH will have the house warm)

If there is no space for all the "equipment" you need to "find it " as its quite unwieldy .. ( ours is ) ducting and ventilation unit ( size of a small fridge) takes up space.
If everything is said and done oil can also be an option , Firebird has outside "condensing" units that are made for the Irish weather. There are heat-pump equivalent options available for hot-water generation as well .. PM me for some direction

Hopefully this helps a bit .. my advise would be though to thoroughly think it through first .. spend money where you end up saving it . . you dont want a lovely house with a heating bill that will be crippling .. we are now three years in gradually making changes to the interior.. when we can :cool:

Heat Recovery

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