Ventilation with solid fuel stove

hydrus21

Hi all.

I recently had a quote to have the cavity walls pumped.Because I have a solid fuel stove in the living area I have to have a 5" wall vent to the outside and all the windows in the property to have trickle vents fitted otherwise I do no qualify for a grant.

Can anyone confirm or clarify this?

Thanks

C3PO

Not sure about the grant but got a stove installed in my new home on Monday and the installer insisted on cutting a vent into the wall - regulatory requirement apparently!

hydrus21

https://www.boards.ie/discussion/comment/121283922#Comment_121283922

Thanks for your reply.

Can i ask what output (KW) your stove was rated at?

listermint

All stoves require ventilation. Rather than a requirement, (which it is) you should view it from a death and safety perspective.

Additionally if you've no airflow the stove simply will not work well what so ever.

Ventilation for the rest of the house is a no brainer for moisture reduction and fresh air flow. Additionally it's a requirement for any SEAI grant work. Often an inspector will check after install to see of Ventilation is in place.

Calahonda52

Am familiar with the hole in the wall but I would ask for the rules re trickle vents

C3PO

https://www.boards.ie/discussion/comment/121283995#Comment_121283995

6kw

ShadowSA

Imagine all the heat escaping out when your stove is not in use, does the trickle vent have a cover so that you can stop the air flow?

dathi

https://www.boards.ie/discussion/comment/121296536#Comment_121296536

the room with the stove must have a vent which is permanently open in other rooms the vent whether it is a hole in wall or trickle vents in windows can be fitted with a cover that can be closed

hydrus21

Solid fuel burners and conventional flued gas appliances require dedicated air supply for correct combustion. I get that.

I dont get the requirements for trickle vents(open or closed) in all other parts of the house.

I want to get cavity wall insulation done to reduce the heat loss. Putting trickle vents in all the windows is the opposite of what i'm trying to acheive.

bfclancy2

https://www.boards.ie/discussion/comment/121298000#Comment_121298000

because a house requires ventilation, prevents damp, moldness, bad air quality etc,

hydrus21

Sorry but I'm missing something here.

I want to increase the thermal integrity of the outside walls.

The bathroom and kitchen have effective extractor fans and windows that open.

I don't get mould or condensation now so why would I get it later?

listermint

https://www.boards.ie/discussion/comment/121298323#Comment_121298323

It's regs. The SEAI will not pay out a grant without proper house ventilation.

Yes the cheapest option is a hole in the wall second cheapest is trickle vents in windows.

Appropriate ventilation is vital not just an extractor in the bathroom.

The little understanding people in this country have around this subject contributes to the high cases of respiratory issues on this island.

Water John

Friend of the daughter had a lucky escape with solid fuel stove. Was chatting on a what's app group and casually asked how could she stop the monoxide alarm that was annoying her. Think she was already a bit fuzzy. They told her to get out straight away. She went to the parents house and because of her clothes and how much she had inhaled she set off the alarm there too. Ventilation is vital, not sure if trickle vents must now be open always.

hydrus21

https://www.boards.ie/discussion/comment/121298517#Comment_121298517

Ok. Thats it then. "It's regs".

Your trickle vents are going to ventilate or create heat loss depending on weather conditions.

Anyone remember going into a stuffy room and opening a window?

Water John

https://www.boards.ie/discussion/comment/121298844#Comment_121298844

No, it's safety.

listermint

https://www.boards.ie/discussion/comment/121298844#Comment_121298844

I don't have trickle vents.

Being particularly interested in the holistic operations of my house and comfort I installed MHRV.

I was fairly certain you didn't take my response seriously which is why I included the bit about people in this country haven't a clue, thus is the high rate of respiratory issues. Seems I was accurate.

hydrus21

Some context.

The property is on an exposed site with plenty of fresh air.

I'm not aware of anyone in the community with respiratory issues .

Are you filtering air because of you locality?

Madd002

Built our house 17yrs, ago engineer came out said wheres vents in walls I said no way had them in house I was renting had to tape all up as so much heat was escaping, I had trickle vents in all windows instead so he was happy enough, had house pumped in 08, didn't do anything, input boiler stove in 09, cosyboarded lower rooms in 15, put double sided stove where we knocked into sunroom 6yrs ago and got spray foam in attic 2 yrs ago, house's lovely and toasty but with all these mods, we are starting to get condensation inside windows so leave one or two trickle vents open all the time now.

Water John

At least everyone be sure to have operating carbon monoxide alarms.

3d4life

Some stoves in some circumstances can support external air input ( i.e. use outside air rather than air inside your house )

This ( long winded ) page paints the picture ( not very well IMO )

https://www.directstoves.com/resources/what-is-an-external-air-kit-for-a-wood-burning-stove/

listermint

https://www.boards.ie/discussion/comment/121299043#Comment_121299043

I'm astonished people think they should live in a sealed box.

Also I'm not astonished governments have to set regulations to save people from themselves.

I've installed a heat recovery system to maintain good air refresh rate and recovery heat back into the house from the existing air. It's unbelievable sensible for the climate in this country.

380,000 people have asthma 1 in 13. 1 in 10 kids.

Opening windows in this day and age of more sealed homes with better building standards is nonsense.

Penn

https://www.boards.ie/discussion/comment/121298323#Comment_121298323

You would get mould or condensation later because you're increasing the thermal integrity of the outside walls.

Mould and condensation is caused by moisture within the air, and is based on a balance between heating, insulation and ventilation. You don't get mould or condensation now because those three things are currently balanced. If you're increasing the insulation in the walls, which will also mean your heating requirements have now changed (as you shouldn't require as much heating to maintain a comfortable temperature), the ventilation also needs to be adjusted. This is done by providing enough background ventilation to provide adequate air changes and reduce moisture in the air.

It's "the regs" in the sense that it's based on enough scientific research and that expert advice deems it to be necessary to the point that the government mandate it. Insulating the walls solves one of your issues. Providing ventilation is required to prevent a different issue.

FJMC

The stove requires combustion air to function. You can get an external kit that provides air directly to the stove from outside so you do not require a vent in the room?

Although I thought the vent requirement only applied to stoves above 5kW?

F

dathi

https://www.boards.ie/discussion/comment/121331259#Comment_121331259

Room sealed appliance

: appliance whose combustion system is sealed from the room in which

the appliance is located and which obtains air for combustion from a ventilated uninhabited

space within the premises or from air outside the premises and which vents the products of combustion directly to

open air outside the premises

that's the definition of a room sealed system taken from the building regs Tgds part J heat producing appliances . it clearly says that the system must be sealed from the room. with a stove even one with an external air supply the home owner can close the dampeners and leave the door open to the room when lit allowing CO gasses into the habitable room.

if you are trying to argue that you dont need a vent because of external air supply then you have to remember you must also comply with TGDS part F ventilation which will require a room vent or mechanical ventilation in the room

FJMC

Sorry - it was whether you needed a specific vent / additional vent for combustion air for the appliance to work.

The combustion air vents can get quite large - more than a window trickle vent - if they are required, depending on the fire size.

I don't think wood burning stoves can be qualified as a sealed appliance - but it was my understanding that they didn't need an additional vent for combustion air if below 5kW output?

F

Sconsey

https://www.boards.ie/discussion/comment/121299397#Comment_121299397

Latest study I could find (2012) does not suggest Ireland's asthma case numbers are exceptional compared to rest of Europe. Not great but far from the worst. Maybe our stats have declined in the last ten years.

https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-12-204/tables/1

dathi

https://www.boards.ie/discussion/comment/121332726#Comment_121332726

taken from building regs TGDs part J

Table 1: Air supply to non-room sealed solid fuel appliances

Any room or space containing an appliance (other than a room sealed appliance) should have a permanent ventilation opening of

free area of 550mm2 per kW of rated output but in no case less than 6,500mm² where air permeability is greater than 5.0m³/(h.m2), or

6,500mm² + 550mm² per kW of rated output above 5kW where air permeability is less than 5.0m³/(h.m²

all appliances but extra ventilation need when its above 5kw

Mellor

https://www.boards.ie/discussion/comment/121298323#Comment_121298323

How is your house currently ventilated (excluding kitchen s d bathroom). If it’s not, it’s non compliant. SEAI won’t issue grants if the house is not compliant.

https://www.boards.ie/discussion/comment/121299043#Comment_121299043

How does the wonderful fresh air gets into your house? You don’t know anyone with asthma?

Most old houses in the countryside and smelly. The fresh air outside does not help.

Yellow_Fern

https://www.boards.ie/discussion/comment/121297525#Comment_121297525

Do you know the thought process in the regulations? Why cant mechanical ventilation be providing this ventilation? I was told by MVHRV guy that MVHRV would be enough

Yellow_Fern

https://www.boards.ie/discussion/comment/121299816#Comment_121299816

Ventilation requirements based on scientific research?, not so sure. they make many crude assumption in a size fits all approach. They assume windows are not opened. Adding insulation does not increase the risk of mould per se. It is more to with the case that after insulation, the room may now as humid as before but also warmer and thus carrying more water in the air.

Mellor

https://www.boards.ie/discussion/comment/121342137#Comment_121342137

A mechanical system can provide air to a stove. Prior to MHRV, fans supplying air to a stove was about the only mechanical ventilating you seen in domestic Ireland. In order for MHRV to supply air to a stove, it has to have that ability designed into it. Not sure why you think it can't.

https://www.boards.ie/discussion/comment/121342166#Comment_121342166

Yes ventilation requirements are based on scientific research. We need air to survive, I wouldn't have thought that was controversial. Using stove in unvented rooms has literally killed people.

There is no assumption that one side fits all. There is no assumption that windows are not opened. Seems like you are making the incorrect assumptions tbh.

Adding insulation changes the dew point within the fabric. Which absolutely does impact the risk of interstitial condensation. As does airtightness.

Adding insulation doesn't actually change the temperature. It changes the energy required to reach a temperature. In a situation that controlled by thermostat, there would be no change to the air temp not the humidity. But risk of interstitial condensation might occur. You are thinking of morning condensation on cold walls, that is not the only type.

Field east

Cleaned my solid fuel stove 3 weeks ago . Partner said that she found it harder than normal to lite the fire. Fire then got very hot and room began to smell differently to normal smell . I put it down to the stove being very, very hot. We decided to vacate the room as smell was beginning to be uncomfortable and daughter ‘s eyes were beginning to be affected.

following morning, I removed the stove to check the flue and got about 7 litres of crinkle. I was very surprised. It was found about 2 to 3 feet up the flue . CO came to mind but I understand that CO does not smell but it could have been still there with some other gas being produced which caused the smell. I have CO alarms fitted but one in the next room went off . But on checking it , one battery was almost completely flat.

MY MESSAGE. Make sure that there is ventilation In area where stove is AND get to know your chimney re how often it should be cleaned. I burn very dry wood and I brushed this stove twice a year and it worked perfectly - and always getting very little crinkle. Now I do not know what is going on - having to clean it twice within a month. I will, from now on , keep an EYE on how easy it is to light and be more sensitive to smells

Yellow_Fern

https://www.boards.ie/discussion/comment/121344833#Comment_121344833

Thanks. I am glad to learn about the stove rules. I appreciate that. Im not just talking about heating stoves. Also referring to solid fuel or oil ovens. What do you mean designed for it? Isn't the idea of the ventilation to prevent occupants from CO, not to fuel the stove which has its own source of O2?

>Adding insulation doesn't actually change the temperature.

In a theoretical sense but in practise, but yet a house may become warmer due to human behaviour and because a lot of people are not using thermostats. I imagine many, if not most, Irish people are not aiming for steady-state heating.

>There is no assumption that one side fits all. There is no assumption that windows are not opened. Seems like you are making the incorrect assumptions tbh.

To my knowledge, that isn't true. Ventilation requirements for hole in the wall vents assume windows are not opened. You can easily meet ventilation needs with an open window in that room.

>It changes the energy required to reach a temperature. In a situation that controlled by thermostat, there would be no change to the air temp not the humidity. But risk of interstitial condensation might occur.

Ok fair enough but often internal ventilation controls are not intended to ventilate the interstitial conditions. Is a bathroom vent going to ventilate a cavity behind a warmboard? I think only if it is designed to do so.

dathi

"To my knowledge, that isn't true. Ventilation requirements for hole in the wall vents assume windows are not opened. You can easily meet ventilation needs with an open window in that room".

no the only time "purge ventilation " ie an open window can be used for ventilation on its own, is when it is in a room with a toilet that does not have a bath or shower in the room. all other rooms must have other forms of ventilation

listermint

https://www.boards.ie/discussion/comment/121350311#Comment_121350311

Designed for it means specifically the MHRV is designed for it. I.e to volume of air supplied to the space is enough to cater for the consumption of the people in the room and the type of equipment within that room. Also that their is enough supplies fitted (number) and their locations within that space.

Designed for.

Mellor

https://www.boards.ie/discussion/comment/121350311#Comment_121350311

By designed for, I mean the MHRV system needs to be designed for deal with a stove. Which is a different requirement that say a bathroom. Pretty basic stuff, meh system are design for their specific space requirements. You can't just drop a stove into a room that has an existing MHRV system and assume its all good.

Isn't the idea of the ventilation to prevent occupants from CO, not to fuel the stove which has its own source of O2?

A stove needs supply and exhaust. Not all stoves have there own source of O2. If you have a room sealed stove, with its own air supply, there is not need for a permanent vent to the room. The vent is required specifically when the stove is fed from the room.

In a theoretical sense but in practise, but yet a house may become warmer due to human behaviour and because a lot of people are not using thermostats. I imagine many, if not most, Irish people are not aiming for steady-state heating.

A house would only become warmer if prior the occupants where unable to heat it enough previously. But for most people, the insulation simply means they reduce the heat energy they need to get to their comfort level. Most people and not aiming to achieve the hottest temperature they can.

To my knowledge, that isn't true. Ventilation requirements for hole in the wall vents assume windows are not opened. You can easily meet ventilation needs with an open window in that room.

Then your knowledge is misinformed. Have you actually look at the requirements?

The requirements consider windows, that should be obvious as having windows for purge ventilation is itself a requirement. Windows provide purge ventilation, not background ventilation. Pretty important to understand the two. Most people do not open their windows 365 days of the year. So its not smart or advisable to rely on windows for background ventilation.

It's pretty unlikely that somebody is light the fire for heat, and open the window to vent the room at the same time. I mean, that would technically work, but isn't simply isn't how people operate. So relying on a window to the provide ventilation to a room with an open heat source is not safe. Hence why a permanent vent is needed.

Ok fair enough but often internal ventilation controls are not intended to ventilate the interstitial conditions. Is a bathroom vent going to ventilate a cavity behind a warmboard? I think only if it is designed to do so.

You're misunderstanding how ventilation helps here. Ventilation doesn't prevent interstitial condensation by ventilation the interstitial space. It prevents it by ventilating the air inside the space. Using your bathroom fan as an example.

A bathroom with the shower on might get steamed up to 100% humidity, and a few degrees warmer than the outside air. Extract ventilation removes that air, which is replaced by normal air drawn in. If that ventilation wasn't there, the air would seep (convect) into the walls, and condense as it gets cooler.

Depending on wall construction, cavities are required to be ventilated. But this needs to be a separate ventilation path to the outside, not via the room

You cannot design a MVHR unit to work with a solid fuel stove.a MVHR is designed to work on balanced input and output air supplies in a sealed home. The huge volumes of air a solid fuel stove draws will overwhelm the MVHR.

The only type of stove that can be matched to MVHR is one which draws dedicated air from outside. Inadequately supplied stoves will reduce the oxygen in a room to dangerous levels and generate CO which could escape into the room.

Basically Irish homes generally have inadequate ventilation which presents many health risks and so SEAI is using its grant system to ensure that all homes it deals with meet a minimum standard for ventilation which is why the insist on trickle vents.

Yellow_Fern

https://www.boards.ie/discussion/comment/121353984#Comment_121353984

So you can confirm, internal combustion with its own air sources does not need fixed opening vents? Wish this information was clearer online.

>A house would only become warmer if prior the occupants where unable to heat it enough previously. But for most people, the insulation simply means they reduce the heat energy they need to get to their comfort level. Most people and not aiming to achieve the hottest temperature they can.

Nope. It is highly unlikely that people are not using steady-state heating. It is very easy to see this. The BER predicts that each higher uses substantially less than the lower grade, over 10%. Cumulatively, the flawed BER system predicts you could reduce energy use by 92% from D to A, but actual real world data from the CSO shows that we only see a 26% drop in gas use by m2 between D to A.

See, the BER system is a system developed by engineers, and fundamentally that is a mistake as heating is used by humans so you actually need to involve social scientists like economists who can take into account factors like the rebound effect.

>You're misunderstanding how ventilation helps here. Ventilation doesn't prevent interstitial condensation by ventilation the interstitial space.

D'oh! You said it did. Please stop spreading misinformation "But risk of interstitial condensation might occur."

> It prevents it by ventilating the air inside the space. Using your bathroom fan as an example.

I know. I never said anything to the contrary.

Yellow_Fern

https://www.boards.ie/discussion/comment/121351148#Comment_121351148

So you are confirming what I said. Thanks! This requirement is a major flaw and waste of energy in my opinion. Windows will yield the required values but the legislation does not allow for that.

https://www.boards.ie/discussion/comment/121357792#Comment_121357792

The issue with.open windows approach is that for the critical periods of the year people simply don't in an effort to save heat. That leads to poisonous air and mold issues.

The ventilation requirements are there to prevent people harming themselves.

I am totally against wall vents because they do undermine airtightness efforts - but some form of guaranteed ventilation which cannot be defeated is essential.

Yellow_Fern

https://www.boards.ie/discussion/comment/121357816#Comment_121357816

Some uneducated people dont. Others will open the windows adequately, while many houses are underoccupied and do not need any windows opened to achieve adequate air changes, think about empty nesters, or the many who dont shower/ bath daily.

Mellor

https://www.boards.ie/discussion/comment/121354015#Comment_121354015

You could design a mechanical system to cope with a open stove. It's simply a supply air requirement. But it's more complicated than a standard system, and would preform less well - so really don't see why anyone would.

https://www.boards.ie/discussion/comment/121357826#Comment_121357826

The building regs cannot assume that most people are sensible since evidence points to the opposite conclusion.

However the building regs are sitting on the fence, trying to enforce energy efficiency by been prescriptive but then issuing a part which is minimally prescriptive regarding essential ventilation.

Since every house is now required to meet A grade it should also be required to incorporate mechanical heat recovery ventilation by design.

You cannot have a truly A rated house without mechanical ventilation and the passivhouse standards understood this 20years ago.

https://www.boards.ie/discussion/comment/121357841#Comment_121357841

The solution is a dedicated air supply to the stove, a system which has existed for decades.

Mellor

https://www.boards.ie/discussion/comment/121357784#Comment_121357784

Have you actually looked up the requirements? You are making a lot of really bad assumptions.

So you can confirm, internal combustion with its own air sources does not need fixed opening vents? Wish this information was clearer online.

That's literally started in plain English. It's clear that a room sealed stove does not require a separate vent to the room. And such a vent couldn't supply a stove.

Nope. It is highly unlikely that people are not using steady-state heating.

I didn't mention steady state heating. Nor is it relevant to the part you quoted. What do you think steady-state heating is?

It is very easy to see this. The BER predicts that each higher uses substantially less than the lower grade, over 10%. Cumulatively, the flawed BER system predicts you could reduce energy use by 92% from D to A, but actual real world data from the CSO shows that we only see a 26% drop in gas use by m2 between D to A.

I think your mistake there is assuming that real world energy performance of a dwelling exactly matches BER estimate (spoiler alert: it doesn't).

I haven't seen the CSO data that you refer to, but I'd be interested if you have a link. Agree that the BER system is flawed.

Regardless, even if people were deciding to heat their houses higher than previously, the requirement for ventilation is still there, so its moot.

D'oh! You said it did. Please stop spreading misinformation "But risk of interstitial condensation might occur."

LMFAO, what misinformation. Really cementing your ignorance there.

Interstitial condensation can occur, ventilation helps prevent it, it doesn't prevent it by venting the interstitial space.

If you think there is a contradiction there, then you don't understand any of that.

I know. I never said anything to the contrary.

You (incorrectly) implied it was required to prevent condensation.

Ok fair enough but often internal ventilation controls are not intended to ventilate the interstitial conditions. Is a bathroom vent going to ventilate a cavity behind a warmboard? I think only if it is designed to do so.

It's not what is required.

So you are confirming what I said. Thanks! This requirement is a major flaw and waste of energy in my opinion. Windows will yield the required values but the legislation does not allow for that.

He confirmed what you said was wrong. Windows cannot provide background ventilation as you claimed.

Some uneducated people dont. Others will open the windows adequately, while many houses are underoccupied and do not need any windows opened to achieve adequate air changes, think about empty nesters, or the many who dont shower/ bath daily.

How often do you open the windows in every room in winter?

Those don't shower daily? That's a new one. Somebody who doesn't wash will have less bathroom steam, so they need the air changes to get rid of the whif of BO

listermint

2 things

Building standards can't rely on people to do the right thing and open windows at will. They simply won't.

People are not willing to spend the money on MHRV. It's very pricey.

This leaves the situation where the cheapest most ubiquitous and safest option is dumb fixed natural ventilation. You might not like it but it is what it is.

What's funny is despite the absolute fantastic characteristics of MHRV is unbelievably difficult to demonstrate, show or promote it with people. You'd have to be living in a house for a good while with and without it installed to see how good it is. Otherwise people just look at the cost and say what's the point.

Mellor

https://www.boards.ie/discussion/comment/121357848#Comment_121357848

Could do is not the same as should do. You do realise I’m not recommending open fires or stoves? I’m pointing out its mechanically possible.

sydthebeat

https://www.boards.ie/discussion/comment/121359156#Comment_121359156

People are not willing to spend the money on MHRV. It's very pricey.

i wouldn't agree with that.

in my experience about 75% of one off building clients are installing MHRV system. In the big scheme of things people view a cost of approx €7k to reduce your heat load and thus electricity costs, prolong teh life of the heat pump and, most importantly, live more healthily, as being well worth it.

in my experience the ones who routinely do not install MHRV systems are building developers because the regs as they are written allow for cheaper natural ventilation in less air tight houses.

MVHR was one of the first things I decided was essential my my house retrofit. If your seeking to achieve high insulation and airtightness you are going to slowly poison yourself otherwise. Long term health effects would be horrendous.

listermint

https://www.boards.ie/discussion/comment/121362670#Comment_121362670

One of housing makes up what percentage of housing construction?

Even in renovations MHRV is not a priority.

I have it, I self installed it was still quite expensive and I've yet to meet one person in real life whom ive showed it to and told them what it does and why say to me 'oh yes we must have that'.

Consider your experience is quite narrow and one off builds would obviously want the best of tech incorporated into their new build.

sydthebeat

https://www.boards.ie/discussion/comment/121362703#Comment_121362703

When you say "people are not winning to spend their money on MHRV" then obviously you are NOT talking about developer driven housing, as people then do not have a choice in the matter.

the point im making is when people are actually given a choice, they DO go for MHRV