Can you retrofit a Heat Recovery Ventilation (HRV) system

PaidV

Hi all, would appreciate some advice. We extensively renovated a bungalow a few years ago and I really regret not getting a HRV system, is it possible to retrofit or would I be wasting money?

xl500

PaidV wrote: »

Hi all, would appreciate some advice. We extensively renovated a bungalow a few years ago and I really regret not getting a HRV system, is it possible to retrofit or would I be wasting money?

You will get answers that they are best installed during renovations due to airtightness tests etc

I retrofitted a system in my Home when I was upgrading insulation It is a 1960s Semi very poor BER I installed External Insulation closed up old external Vents and installed HRV now of course its not up to passive house standards but the HRV is Great always Fresh air no condensation in Bathrooms or Bedrooms I think they are a great addition to any house

BER is now B3 which is great for a 1960s Cavity Block Semi

PaidV

Thanks for the reply. Mine is an early 1990s bungalow but we extensively renovated and its circa B1 now if memory serves me.
Any thoughts on n air source heat pump with the HRV. I currently have oil central heating...

xl500

PaidV wrote: »

Thanks for the reply. Mine is an early 1990s bungalow but we extensively renovated and its circa B1 now if memory serves me.
Any thoughts on n air source heat pump with the HRV. I currently have oil central heating...

Sorry have no experience of Heat Pumps but with a B1 Rating it could take a very long time to return your investment with fuel savings, I presume your Heating Costs are Low with a B1 rating

I would definitely go for a HRV though it's not just about saving money the internal atmosphere and comfort is so much better with one

Muahahaha

PaidV wrote: »

Hi all, would appreciate some advice. We extensively renovated a bungalow a few years ago and I really regret not getting a HRV system, is it possible to retrofit or would I be wasting money?

Looking into this myself and the answer for retrofits seems to be ductless heat recovery systems. By going ductless it avoids the need for extensive remedial work connecting ducts from every room to a unit in the attic. A 50sqm space would need two ventilation units and when set automatically one sucks and the other blows for a minute then they swap over function and so on.

If you google around there are now a few single room MHRV units on the market at about €300-€400 a piece, these have two ducts inside them so you only need a single unit for a large room. Some versions have add on extras like touch screen controls where you can monitor temps, humidity, and it can control up to 12 units at a time. They can be installed by any competent DIYer.

Will likely go down this route myself when other works are done, just for the kitchen/living room at first and then extend it later to other rooms. Seems to be a no-brainer going ductless for an older building, likely works out cheaper too.

H.E. Pennypacker

Muahahaha wrote: »

Will likely go down this route myself when other works are done, just for the kitchen/living room at first and then extend it later to other rooms. Seems to be a no-brainer going ductless for an older building, likely works out cheaper too.

Are you thinking of Demand Controlled Ventilation? Will you not have to run wiring to each unit? I had considered this as an option but when I costed it for the entire house, MHRV was cheaper and less work overall (in a bungalow)

Muahahaha

H.E. Pennypacker wrote: »

Are you thinking of Demand Controlled Ventilation? Will you not have to run wiring to each unit? I had considered this as an option but when I costed it for the entire house, MHRV was cheaper and less work overall (in a bungalow)

Yeah Id imagine installing MHRV in a bungalow with lots of attic space is a lot less hassle than a 2 or 3 storey.

Wasnt thinking DCV but had looked at it last year, specifically ductless DCV as my house would need a lot of work to run ducts. But DCV only changes the air, it doesnt heat it so I ruled it out.

But since then there are new units after coming onto the market that provide MHRV but through a single unit attached to the inner wall and ducted directly outside. The unit has two ducts inside it and some sort of device that takes the heat from the extracted air and puts it into the intake air. They say each unit covers about 50sqm so an average 3 bed semi could have one unit downstairs and one up. Units are approx €1000 a piece so not cheap but as they seem to be new I'm hoping prices come down and more competition to enter the market. I havent seen any reviews of them yet but one attraction seems to be very low running costs (about 5w per hour) and not having the need to clean out ducts.

derekbro

Muahahaha wrote: »

Yeah Id imagine installing MHRV in a bungalow with lots of attic space is a lot less hassle than a 2 or 3 storey.

Wasnt thinking DCV but had looked at it last year, specifically ductless DCV as my house would need a lot of work to run ducts. But DCV only changes the air, it doesnt heat it so I ruled it out.

But since then there are new units after coming onto the market that provide MHRV but through a single unit attached to the inner wall and ducted directly outside. The unit has two ducts inside it and some sort of device that takes the heat from the extracted air and puts it into the intake air. They say each unit covers about 50sqm so an average 3 bed semi could have one unit downstairs and one up. Units are approx €1000 a piece so not cheap but as they seem to be new I'm hoping prices come down and more competition to enter the market. I havent seen any reviews of them yet but one attraction seems to be very low running costs (about 5w per hour) and not having the need to clean out ducts.

Is it something like this https://www.amazon.co.uk/gp/product/B004VW3RGW
Are they any good? Thinking about a couple of them for my place.

0lddog

derekbro wrote: »

Is it something like this https://www.amazon.co.uk/gp/product/B004VW3RGW
Are they any good? Thinking about a couple of them for my place.

Any views on putting one of these in a blocked up fireplace and installing a flexible duct up the chimney for the fresh air ( or maybe stale air.....? ) ?

Muahahaha

derekbro wrote: »

Is it something like this https://www.amazon.co.uk/gp/product/B004VW3RGW
Are they any good? Thinking about a couple of them for my place.

Cant comment if they are any good as I havent sorted ventilation yet. Mitsubishi do single unit MHRVs but the ones I'm hoping will drop in price somewhat is the Lunos e2. There are other options on the market but the Lunos seems to get decent reviews. However Im not seeing much that can be controlled via an app and synced with smart home devices like Google Home and Alexa. I would want features where you can set the target temperature/humidity of the unit and control it remotely. I think the market for these units is new enough so we are not yet seeing full features.

I wont be purchasing for at least another 6-9 months anyway so would expect more options on the market then, especially as ducting a house is quite expensive in a retrofit situation so these single units seem to be a good way of getting MHRV without the need for it.

metricspaces

Muahahaha wrote: »

Yeah Id imagine installing MHRV in a bungalow with lots of attic space is a lot less hassle than a 2 or 3 storey.

Wasnt thinking DCV but had looked at it last year, specifically ductless DCV as my house would need a lot of work to run ducts. But DCV only changes the air, it doesnt heat it so I ruled it out.

But since then there are new units after coming onto the market that provide MHRV but through a single unit attached to the inner wall and ducted directly outside. The unit has two ducts inside it and some sort of device that takes the heat from the extracted air and puts it into the intake air. They say each unit covers about 50sqm so an average 3 bed semi could have one unit downstairs and one up. Units are approx €1000 a piece so not cheap but as they seem to be new I'm hoping prices come down and more competition to enter the market. I havent seen any reviews of them yet but one attraction seems to be very low running costs (about 5w per hour) and not having the need to clean out ducts.

I think this is the product you are describing? http://www.lunos.ie/product-details.php?ID=252

Muahahaha

metric that link isnt working for me. But yes you are right, the company is Lunos and the product Im thinking of going for is the Lunos eGo which only requires one unit at the fans work both intake and exhaust air. As said Im not undertaking it for a good few more months so hope to see some reviews in the mean time on this Amazon listing https://www.amazon.co.uk/Decentral-Ventilation-Recovery-Dezentrales-Lraumbel/dp/B01080T0HA/ref=sr_1_1?keywords=lunos+ego&qid=1562191205&s=gateway&sr=8-1

Blowheads

Hi,
Lot of installers fear the word retrofit. We did it in a 2 story house 3 years ago, great job. Bungalow should be easy to run the ducts to all the rooms. We ran ours downstairs through cloakroom. Obviously needs good other insulation, windows and doors etc. Mitsubishi system

randombar

What kind of prices are people looking at for a retrofit to a two story. Reckon the ducting would be ok going through wardrobes and the likes.

Blowheads

GaryCocs wrote: »

What kind of prices are people looking at for a retrofit to a two story. Reckon the ducting would be ok going through wardrobes and the likes.

Depends on how many rooms etc and what part of the country you're in. Think 3.5k as a ballpark

randombar

Blowheads wrote: »

Depends on how many rooms etc and what part of the country you're in. Think 3.5k as a ballpark

Cork 4 beds, 3 baths upstairs, 5 rooms and a bath downstairs.

3.5k isn’t bad.

House is well insulated. It’s just windows open in winter to get fresh air in drives me mad.

Would be hard to calculate Roi on it id say.

Blowheads

GaryCocs wrote: »

Cork 4 beds, 3 baths upstairs, 5 rooms and a bath downstairs.

3.5k isn’t bad.

House is well insulated. It’s just windows open in winter to get fresh air in drives me mad.

Would be hard to calculate Roi on it id say.

Something similar as ourselves so. Check your runs and how you can get to the rooms downstairs. Maybe not possible to get to them all like utility or conservatory but then again no need to get all just for the sake of it.

We ducted the hot press as the warm room (typically the kitchen) as well as the bathrooms and the kitchen. We also did it in 2 stages, upstairs first and then downstairs.

Sealed up all the vents in the rooms and windows. Get a few quotes as there can be big difference in prices and buy a system a little larger than you actually need so you can run it at half speed as opposed to a smaller system at full speed

randombar

Blowheads wrote: »

Something similar as ourselves so. Check your runs and how you can get to the rooms downstairs. Maybe not possible to get to them all like utility or conservatory but then again no need to get all just for the sake of it.

We ducted the hot press as the warm room (typically the kitchen) as well as the bathrooms and the kitchen. We also did it in 2 stages, upstairs first and then downstairs.

Sealed up all the vents in the rooms and windows. Get a few quotes as there can be big difference in prices and buy a system a little larger than you actually need so you can run it at half speed as opposed to a smaller system at full speed

I reckon I'd be able to do a bit of it myself, once I got a couple of rooms done and the house was sorted out for air tightness.

Thanks for the info.

Markcheese

Do people keep their regular cooker hood extractor fan(or is it considered a no no, cos I've seen several recirculating/filtration ones and they're brutal...

FlipperThePriest

This is something I've been thinking about of late. Currently upgrading attic insulation. Next step will be upgrade the oil boiler and heating controls... then hopefully mhrv. Bungalow, fairly airtight for the age.

https://www.bpcventilation.com/vent-axia-kinetic-bh-kit

Has anyone ever used anything like the above? Is it doable diy? Or would you be better off going for a reputable supplier / installer? For example the above with ducting for 6 rooms would probably cost about €2k for my place.

randombar

zippy84 wrote: »

This is something I've been thinking about of late. Currently upgrading attic insulation. Next step will be upgrade the oil boiler and heating controls... then hopefully mhrv. Bungalow, fairly airtight for the age.

https://www.bpcventilation.com/vent-axia-kinetic-bh-kit

Has anyone ever used anything like the above? Is it doable diy? Or would you be better off going for a reputable supplier / installer? For example the above with ducting for 6 rooms would probably cost about €2k for my place.

There's a thread on here about someone doing themselves. The actual work is ok I'd say it's more about testing for air tightness that I think you'd need someone for. i.e. Could install the system but it might run very poorly if the air tightness isn't done.

Also might be better to do this before attic installation if you are getting it done. Access etc.

Muahahaha

Markcheese wrote: »

Do people keep their regular cooker hood extractor fan(or is it considered a no no, cos I've seen several recirculating/filtration ones and they're brutal...

Not sure if it is a no no, I think some modern extraction units can have a baffle in them that only allows the air to go one way. Definitely try to avoid recirculating ones, they are next to useless if you do any cooking that involves high heat and lots of smoke. Did a renovation myself recently and after years of smokey kitchens in rentals I completely over specced the extraction unit to solve this problem, the thing sounds like a wind tunnel and is noisy when operating but no more smokey kitchens after cooking a steak or a stir fry in a wok.

randombar

Any recommendations of people to talk to in Cork about this?

FlipperThePriest

GaryCocs wrote: »

There's a thread on here about someone doing themselves. The actual work is ok I'd say it's more about testing for air tightness that I think you'd need someone for. i.e. Could install the system but it might run very poorly if the air tightness isn't done.

Also might be better to do this before attic installation if you are getting it done. Access etc.

I've spoken to guys who say if your house is tight enough that you need to open windows for condensation etc, then it's tight enough to benefit from mhrv. I spoke with a guy in BPC ventilation just a short while after my last post, he said they encourage DIY installs, 2 out of 3 of their sales are DIY, they will commission the install to make sure everything's as it should be.

I agree re. attic insulation, but it's unfortunately not going to happen. I'm really only adding a layer to what's already there anyway, but yes, access won't be as good.

Markcheese wrote: »

Do people keep their regular cooker hood extractor fan(or is it considered a no no, cos I've seen several recirculating/filtration ones and they're brutal...

I believe you'd replace your cooker hood with a recirculating hood... yes on its own it might not be great, but once you've the mhrv installed, all it's really doing is filtering out grease and oil over the cooker and recirculating to allow the mhrv do the venting.

randombar

Found the old thread.

https://www.boards.ie/vbulletin//showthread.php?t=2057496673

Any recommendations for installers in Cork? If I'm doing this I would try and do the ducting myself and get an installer to commission.

I might need them at the start to show me where to put things though.

Shefwedfan

I have been thinking about this for a while....think it is best option. Live in bungalow so easy access to all rooms etc

Anyone know companies that are doing this? self install I dont think will work.....

randombar

Shefwedfan wrote: »

I have been thinking about this for a while....think it is best option. Live in bungalow so easy access to all rooms etc

Anyone know companies that are doing this? self install I dont think will work.....

Go for it!!! We'll get a good deal

Shefwedfan

GaryCocs wrote: »

Go for it!!! We'll get a good deal

Im already looking at quotes



Also found a quote from UK company that ship direct.....:-) I forgot I asked for it

P2C

I installed my own mhrv although not a retrofit. I can’t see any issue why not into a bungalow as long as you have attic space that can house the unit and insulated ducting. In a two story as long as you can hide or box in the ducts why not. The biggest hassle would be cutting the plasterboard but that’s not difficult. I would get a blower door test done first to asses if the house is airtight enough as manufacturers have specs

Shefwedfan

P2C wrote: »

I installed my own mhrv although not a retrofit. I can’t see any issue why not into a bungalow as long as you have attic space that can house the unit and insulated ducting. In a two story as long as you can hide or box in the ducts why not. The biggest hassle would be cutting the plasterboard but that’s not difficult. I would get a blower door test done first to asses if the house is airtight enough as manufacturers have specs

Attic is huge.....just dont have the balls to take on installation solo

randombar

Shefwedfan wrote: »

Im already looking at quotes



Also found a quote from UK company that ship direct.....:-) I forgot I asked for it

How much were they looking for.

Anyone any recommendations for a blower test?

Thinking a uv/escaping heat one would be good too.

Shefwedfan

GaryCocs wrote: »

How much were they looking for.

Anyone any recommendations for a blower test?

Thinking a uv/escaping heat one would be good too.

3-4K UKIP plus vat depending on model, 3000 sq ft house

randombar

Shefwedfan wrote: »

3-4K UKIP plus vat depending on model, 3000 sq ft house

Ouch!!

Shefwedfan

GaryCocs wrote: »

Ouch!!

6k for install budget price so far....how much do these save?

randombar

4,500 first one back, no air tightness test or improvements done as part of that though

Blowheads

Shefwedfan wrote: »

6k for install budget price so far....how much do these save?

You'd know the good times are back

Shefwedfan

Im struggling with this. It is something I think is perfect for the house but the prices I am getting are crazy.

What sort of savings would you expect? would it be even a 30% reduction in heating fuel or more? I know it depends on the air tightness but just a high level number.,

At the moment based on the budget numbers I am getting it is just a terrible business case to bring to the board :-) e.g. wife

Blowheads

Shefwedfan wrote: »

Im struggling with this. It is something I think is perfect for the house but the prices I am getting are crazy.

What sort of savings would you expect? would it be even a 30% reduction in heating fuel or more? I know it depends on the air tightness but just a high level number.,

At the moment based on the budget numbers I am getting it is just a terrible business case to bring to the board :-) e.g. wife

This ain't a heating solution. This is used to bring in fresh clean air that's pre warmed by the exchanger. It's almost mandatory in an air tight house since there is no outside fresh air getting in to replace the stale, used and moist air inside.

I don't think you can think of this as a saving, though I'm sure someone from some company will sell you on that... We put it in to reduce condensation etc and have opening windows and vents in cold temperatures. It does that very well. Pm if you want more info

Darando

Do any of the MHRV ducts come in small rectangular sections rather than the larger round ducts - I have a few stud walls going from bottom to top of house which could work as a route to the kitchen meaning space is tight. Don't have option really for other routes apart from boxing sections (which look poor unless in wardrobe/cupboards I think)

0lddog

Shefwedfan wrote: »

Im struggling with this. It is something I think is perfect for the house but the prices I am getting are crazy. ........
At the moment based on the budget numbers I am getting it is just a terrible business case to bring to the board :-) e.g. wife

Think of it as something that could make it nicer to live in the house - a bit like having the house decorated for the first time in decades ....;)

Shefwedfan

Blowheads wrote: »

This ain't a heating solution. This is used to bring in fresh clean air that's pre warmed by the exchanger. It's almost mandatory in an air tight house since there is no outside fresh air getting in to replace the stale, used and moist air inside.

I don't think you can think of this as a saving, though I'm sure someone from some company will sell you on that... We put it in to reduce condensation etc and have opening windows and vents in cold temperatures. It does that very well. Pm if you want more info

So my current setup is....heating goes on in morning....house nice and toasty....miss Shefwed gets up and opens all the windows in house.


House is like ice box. Heating goes on an heats house back up. Today I arrive home to stove going full blast while all windows are open.



What I mean by heat gaining is that because this is warming the air while pumping back in it "should" reduce the heating requirements because I am not opening the windows to ventilate the house

0lddog

Even if it could reduce your heating requirement, do you think that you will be able to reprogram The Controller ?

To do what you want you may need to swap your Controller for a different model

Would it be worth it ?

josip

Retrofitted a 3 bed semi in 2010 for €4,000 installed (a basic ProAir unit).
Never had a problem with it.
Connecting the hob extractor to it is a no-no I thought ? You don't want any build up of grease in the ducts where it will be impossible to clean.
We were gutting the house at the time so there was little overhead installing.
House became a B something after it all. Not airtight but I siliconed everything that looked like a hole so it holds heat well.

Blowheads

Shefwedfan wrote: »

So my current setup is....heating goes on in morning....house nice and toasty....miss Shefwed gets up and opens all the windows in house.


House is like ice box. Heating goes on an heats house back up. Today I arrive home to stove going full blast while all windows are open.



What I mean by heat gaining is that because this is warming the air while pumping back in it "should" reduce the heating requirements because I am not opening the windows to ventilate the house

Controller needs regular reprogramming alright but it will definitely cut your bills if she's opening all the windows all the time..

listermint

Shefwedfan wrote: »

So my current setup is....heating goes on in morning....house nice and toasty....miss Shefwed gets up and opens all the windows in house.


House is like ice box. Heating goes on an heats house back up. Today I arrive home to stove going full blast while all windows are open.



What I mean by heat gaining is that because this is warming the air while pumping back in it "should" reduce the heating requirements because I am not opening the windows to ventilate the house

Have you blocked up all the vents? because these sounds like an incredibly poorly thought out means of heating and ventliation in the house.

Shefwedfan

listermint wrote: »

Have you blocked up all the vents? because these sounds like an incredibly poorly thought out means of heating and ventliation in the house.

The house has no vents!! I done a retrofit a few years back.....so one bit at a time.....

josip

Blowheads wrote: »

Controller needs regular reprogramming alright but it will definitely cut your bills if she's opening all the windows all the time..

Only if she stops opening the windows.

There's no guarantee they'll listen to the logic and will still decide the house could do with 'ventilating'.

Speaking from experience.

randombar

Anyone else get quotes back?

Shefwedfan

0lddog wrote: »

Think of it as something that could make it nicer to live in the house - a bit like having the house decorated for the first time in decades ....;)

I will do it, just not now....I went solar pv instead as better business case

I want to do a bit more on insulation before heat recovery

s7ryf3925pivug

Would positive input ventilation be preferable to HRV for older buildings that are likely to have significant air leakage?

Are there PIV systems with good HEPA filters? (PM2.5 levels go up to over 50 pretty much immediately when a window is open thanks to solid fuel burning in the area during the winter.)

Shefwedfan

Tatiana Rough Shot-putter wrote: »

Would positive input ventilation be preferable to HRV for older buildings that are likely to have significant air leakage?

Are there PIV systems with good HEPA filters? (PM2.5 levels go up to over 50 pretty much immediately when a window is open thanks to solid fuel burning in the area during the winter.)

Interesting as I seen these and just thought they where mini HRV


Could be interesting solution to stop condensation in my house


https://smartheat.ie/drimaster/