Ventilation with solid fuel stove

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

Shoog

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.

Shoog

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.

Shoog

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.

Shoog

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.

Shoog

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

listermint

https://www.boards.ie/discussion/comment/121362755#Comment_121362755

But that's not true. Look at retrofits and renos, my cousins company does these for a wide array of budgets. And they have very low levels of MHRV. It's still in its absolute infancy here sadly. That's the reality.

People will load up the high end kitchen or flooring before considering MHRV. They'll make just do based on budget.

sydthebeat

https://www.boards.ie/discussion/comment/121362762#Comment_121362762

we're talking about building regulations here, there is no requirement for MHRV in a retrofit fit or renovation.

your words:

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

listermint

https://www.boards.ie/discussion/comment/121362813#Comment_121362813

I'm honestly not sure what you are talking about at this point. I never once mentioned MHRV is a requirement per building regs....

Are you on one ?

sydthebeat

https://www.boards.ie/discussion/comment/121362823#Comment_121362823

why then mention "building standards" in the only post from you which i quoted and am replying to?

either you are talking about building standards or you are not? please clarify?

listermint

https://www.boards.ie/discussion/comment/121362837#Comment_121362837

Read the entire thread. I'm not repeating myself. Never once said mhrv was a standard.

Repolho

I hope OP doesn't mind me piggy backing on their post.

I am doing an energy retrofit at the moment which includes MVHR. I have 5Kw solid fuel stoves in 2 rooms, neither has an external air supply. There are currently no vents in any of the rooms in the house. My old windows had trickle vents but my new ones do not. Do I need to have wall vents installed or is the MVHR sufficient?

sydthebeat

https://www.boards.ie/discussion/comment/121363118#Comment_121363118

so... your NOT talking about building standards then. thank you for clarifying.

listermint

https://www.boards.ie/discussion/comment/121366495#Comment_121366495

Syd, it seems your took the posts up incorrectly. That's on you solely.

Consistently in this thread I have said minimum ventilation is required by regulation. Per the conversations SEAI won't give any grants for work like insulation unless ventilation is proven often with a site visit. In regards Stoves the OP was advised by myself and others that a room containing a stove needs to have a permanent air supply vent or otherwise.

Where the topic moved into MHRV something I'm a big fan off and have installed I said that it can be designed to take account of a stove. I also said that people won't pay for MHRV the volume of installations supports that. And so we are left in a situation where we have open holes in walls which at least a minimum that building regs require.

Again suggest you read the thread or others I've spoken about on the subject. And take the bee out of your bonnet on things I didn't say. Good luck.

listermint

https://www.boards.ie/discussion/comment/121366414#Comment_121366414

I think your MHRV would be badly impacted by the use of the stoves as they will consume a large amount of the oxygen and may also contribute to particles in air quality something most mhrvs are automated to ramp up or down on. You'll probably suffer and inconsistent experience with the system and higher energy use.

It's not ideal. I'd suggest if stoves need to be kept an external supply is sought and they are essentially kept entirely separate from the MHRV. It should simplify it entirely.

sydthebeat

hi listermint, we'll leave it there as theres no point going back over things, but for future reference when i quote a post, thats an indication that i am replying to the contents of that post only, not a general comment on the context of the thread. So in this case what you, or anyone else, said before i quoted you, is completely immaterial to the point i was making.

if im posting in the context of the general conversation, i would not quote anyone.