Airtight stove for house with HRV

imitation

Could anybody give me ball park figures for stoves that are safe to use in a home with HRV, and if possible someplace to purchase them in cork?

bikerboy_ie

Maple marketing in Ballycureen Ind est. Near to cork lighting. Will cost about 3 to 4 thousand for an airtight model

Cuauhtemoc

Quite a lot of Morso stoves can use an external air supply kit.
Not sure of Irish prices first place i found online with prices was the UK. Starting from 875 sterling for the badger which is 6kw max output.


C.

homewardbound11

I am at this in my build at the moment.
Suppliers are almost very careful to say a system is air tight and much prefer to say that the model has an external air intake.
Look for models with closed combustion or room sealed or suitable for houses with mhrv systems. This will narrow down your searches . There seems to be alot of confusion out there.
In the end, is your unit ever really room sealed, as you will be opening it to refuel and seals are prone to wear.
Good luck, your next problem will be getting competent installers. I am installing in a timberframe house with twin walled flues and have already dismissed one stoveman from the site as he seemingly was unaware of regulations, wanted me to supply the ladder and asked my where i wanted to position the stove.? I should have known better. one lesson learned there.

Lightning McQue

Homewordbound

What stove did you buy and who did you buy it from?

Lightning

curaldo

Hello,

Im a little behind most of yee,in the sense that im only about to dig my foundations in the next two weeks, but im looking at multi fuel stoves for the build. the house will be airtight and use hrv so an external air feed is required. It seems 100mm duct is enough to feed the stove. Can put a pipe in the foundations to the outside world. When the stove is closed it should be airtight. Im also looking at the the twin walled insulated flue from Schiedel.

CountyDownStoves seem to very good and will give you good advice on the right stove for the area you want to heat. They also have stoves to suit airtight houses. Murphyheating in Kinvara are also helpful.

homewardbound11

jotul 471/ f373 for wood burning stoves.

I am looking to purchase a barbas c 2 80 inset fireplace for my other room.

Fenton fireplaces or murphys of kinvara are my options. Also check mourne sotves (I think).
If you want someone else ot do all the work try flame by design in cork. I just couldn't afford the full service so am doing it my self.

Lightning McQue wrote: »

Homewordbound

What stove did you buy and who did you buy it from?

Lightning

Bianco

I bought one recently in Nagles in mallow. Have alot of information on these if you need advice. PM me

soldsold

Have any of you found a stove with the following spec:

1) Airtight, or air control
2) Can take external air supply
3) Has back boiler so can get some of the heat out of the room the stove is in
4) Inset/ Insert stove so less surface area than a room stove so less heat output to overheat the room
5) Minimum heat output to room, maximum to boiler - eg 2-3kw to room, 12-15kw to boiler

Thanks!

S

Out Of Order

soldsold wrote: »

Have any of you found a stove with the following spec:

1) Airtight, or air control
2) Can take external air supply
3) Has back boiler so can get some of the heat out of the room the stove is in
4) Inset/ Insert stove so less surface area than a room stove so less heat output to overheat the room
5) Minimum heat output to room, maximum to boiler - eg 2-3kw to room, 12-15kw to boiler

Thanks!

S

I intend on buying a Boru stove to do this job.

FergusD

I've been told by both Mulberry and Stanley that they'll have stoves with an air intake and a back boiler in the Autumn. They won't give me more info than that until closer the time.

Fergus.

JuniorB

soldsold wrote: »

Have any of you found a stove with the following spec:

1) Airtight, or air control
2) Can take external air supply
3) Has back boiler so can get some of the heat out of the room the stove is in
4) Inset/ Insert stove so less surface area than a room stove so less heat output to overheat the room
5) Minimum heat output to room, maximum to boiler - eg 2-3kw to room, 12-15kw to boiler

Thanks!

S

Not sure on the kw of these but here are two that I came across that should fit the bill...

Hakr Zeus - various suitable models
Kobok Chopok - various models (including corner option)

The first is widely available here. The second from one supplier - website seems to be gone but he's answering his phone (I have one ordered - will be delivered in next few weeks!)

dnClar

We are currently in the process of building an airtight house. We went with the ultima frame from Century homes.
We have a 4" pipe for air intake in the centre of the base for the chimney, that we brought in before the frame went up.
We have enquired alot about stoves, and the most reasonable seems to be Stovax stoves, living stone in limerick do them and murphys heating in kinvara.

daveoc16

Hi folks,

Interesting stuff. I'm currently at floor level on a new build myself.
I've been looking for stoves with an external air supply. The only ones i can find are wood burning stoves. Doesn't seem to be any traditional multifuel stoves with external air kit.
I plan to use old style stove in one room and an insert stove (stovax) in the other.
My plan is to carry a 2" duct underfloor from outside to a vent at each fire place (as close as possible to stoves). I'm hoping this will provide plenty air to the stoves. This should eliminate smokey moments and should draughts across door ways etc with the trying to get enough air.
This vent can then be shut when stove not in use without dramatically affecting MHRV.
I'm new to all this. What do ye think, I'm I missing something?

Scartbeg

Have been looking for one for our new build, as we will have MHRV.

The only ones I can find that explicity state they are room sealed are Stovax Riva Plus (small, midi and large) and some Franco Belge models. We are looking for a ~5kW non-boiler.

The Stovax came in around €1400 and the Franco Belge Montfort €850.
We are pretty much decided on the Franco Belge.

We are going with the Schiedel Air chimney system which brings air down a second channel in the stack alongside the flue. Works out about €180/metre.

Poco90

I got a quote at the weekend for a stove with external air supply kit.

7KW Nestor Martin S23 €1650 (said the 5KW version would be €500 cheaper). The chimney liner was €30/metre and I would have to get my own installer which he guessed would charge €500.

Got information from Waterford stanley about one of their stoves and they recommend running a 4" pipe from opposite sides of the house (front to back) and tapping the stove air intake off this. This should negate pressure zones. All I'll be doing is running 2 x 2" pipes under the screed from the front of the house to the stove as my fire is in the centre of the house, so I can't run a 4" pipe.

Hope this helps,
Poco

about2build

Good stuff on here but do any of these stoves incorporate a back boiler as well as the other criteria listed??? Would like to heat water and run 3-4 rads off it as well? Any models or companies in Galway area

rodzer

about2build wrote: »

Good stuff on here but do any of these stoves incorporate a back boiler as well as the other criteria listed??? Would like to heat water and run 3-4 rads off it as well? Any models or companies in Galway area

I built my own house and moved in April 2011. We have mvhr. We got a Stanley Reginald solid fuel boiler stove. Great job as it has the external air duct. No draughts whatsoever. Its great for heating the water too in winter as the solar tubes are dormant. I'm an Arch. Tech. and Ber assessor and my house has an A3 energy rating. Wud liked to have built to passive standards but the cost was just too great. Still very happy though.

about2build

Thanks Rodzer
Is the stove your primary heating system?? If so how many rads kws etc? Also where does the external air duct run? through the screed or where?

about2build

soldsold wrote: »

Have any of you found a stove with the following spec:

1) Airtight, or air control
2) Can take external air supply
3) Has back boiler so can get some of the heat out of the room the stove is in
4) Inset/ Insert stove so less surface area than a room stove so less heat output to overheat the room
5) Minimum heat output to room, maximum to boiler - eg 2-3kw to room, 12-15kw to boiler

Thanks!

S

Soldsold did you find one with all the criteria they are pretty thin on the ground

rodzer

about2build wrote: »

Thanks Rodzer
Is the stove your primary heating system?? If so how many rads kws etc? Also where does the external air duct run? through the screed or where?

No, I have an oil condensing boiler which heats the 2600sq.ft. house. The solid fuel stove can't do this. It gives max. 4kw to the living room and max. 15.8kw to the boiler. We only burn sycamore logs which wouldn't be enough to heat the rads. The key with building is to make it airtight and you will never be cold. The external air duct runs through the screed to a grill on the plinth outside.

about2build

Thanks rodzer...i sent you a pm as well so as to not destroy the thread:)

cappite123

hello all..i am currently building an air tight house and am really wondering about room sealed stoves..will i use a balanced flue or one with an external air supply..anyone got any information on sealed stoves..i also heard that a stove insert under 5kw does not need external air as hrv air will do for it

about2build

Can only use a balance flue for oil or gas stove not solid fuel and the combustion air i.e. the air being burned to create the fire is taken from tthe room it is in unless it is room sealed....this process has nothing to do with the flue you use. MHRV requires a room sealed stove irrelevant of the power it has.....
i'm going for a Boru 600 i which is fully room sealed , insert with back boiler whhich is exactly what i wanted:)

fclauson

cappite123 wrote: »

hello all..i am currently building an air tight house and am really wondering about room sealed stoves..will i use a balanced flue or one with an external air supply..anyone got any information on sealed stoves..i also heard that a stove insert under 5kw does not need external air as hrv air will do for it

Couple of things here

most importantly CO IS A KILLER ITS ODOURLESS, TASTLESS AND INVISIABLE

1 - balenced flue - there are chinmey systems out there which will allow air to be drawn down a separate duct in to the back of the stove and then the hot gases to rise up the chimney in the normal way
From the advice I have received the more preferable option is a duct under the floor from the outside (check size with your fire supplier)

2 - its a big no no to have air being drawn from the room with HRV - in actual fact if your read the regs to the letter even in an airtight house you would still require a hole in the wall in the room with a fire. The reason why its a no no is in the event of the house "depressurising" (extract fan running faster than the supply fan) CO and smoke would be drawn out of the stove into the room

hope that helps

sas

about2build wrote: »

i'm going for a Boru 600 i which is fully room sealed

Is it though?

The spec on their website for this model states
"Available with optional central air intake.(outside air)"

"Optional" suggests that it always has room vents too.

Might be worth double checking.

rodzer

1. If it's true that a stove insert under 5kw doesn't need external air, it has no option then but to take the air for combustion from the room. This means nasty draughts. I wouldbt like to be depending on the hrv for enough air for kindling my stove.
I'd agree, the more preferable option is a duct under the floor from the outside. Mine is 100mm diameter.

2. My house is airtight. I'd hate a hole in the wall in the room with the stove. The stove has external air kit. The HRV takes care of ventilation, co2, radon, carbon monoxide, smelly sneakers, etc. My days of holes in the wall are behind me.

fclauson

fclauson wrote: »

....
most importantly CO IS A KILLER ITS ODOURLESS, TASTLESS AND INVISIABLE

....

Additionally
I will (depite it not being part of domestic regs) be fitting a CO alarm in the room with the stove plus, have a supply and extract in the room plus have a co/co2 dectector in the MHV connected to some form of audiable alarm

rodzer

I've never seen "a co2 detector built into a MVHR system, connected to some form of audiable alarm". Does such a thing even exist? If the MVHR system is doing its job of changing the air very regularly, why would you need a co2 detector?

BryanF

rodzer wrote: »

I've never seen "a co2 detector built into a MVHR system, connected to some form of audiable alarm". Does such a thing even exist? If the MVHR system is doing its job of changing the air very regularly, why would you need a co2 detector?

wouldnt you like to know if there was a source of CO2 from perhaps your stove... and in case the MVHR is helping to spread a fire

rodzer

Interesting points. I presumed the MV system would deal with any co2 before it hung around to do damage. Its worrying to think a house fire could spread throughout the house through the ventilation ductwork. God forbid.

fclauson

this is a big and often unaddressed problem - and you will see other posts from me asking fro MVHR "experts" of which I can find none

I am now working with a couple of UK companies

there are suggesting fire valves in both the sitting/stove room, the kitchen and if I go for an internal heat source other than a HP then in the room which contains that too (e.g. oil burner or gas)

they are also suggesting both supply and extract in the stove room for two reason
1 - so that you can (very slowly due to air volumes) spread the heat around the house
2 - create no negative or positive pressure in the stove room so that when you open the door no smoke/ash gets sucked out the fire

they are also suggesting the system is connected to the fire alarm/smoke detector system so that it shuts down in the event of the alarm being triggerd - no point in feeding the fire/smoke into your bedrooms :mad:

the CO2 detector and humidity detector in the MVHR system will/can control the speed of extract (house empty slows down / big party and lots of gossip system speeds up)

sas

sas wrote: »

Is it though?

The spec on their website for this model states
"Available with optional central air intake.(outside air)"

"Optional" suggests that it always has room vents too.

Might be worth double checking.

I can confirm having spoken to Boru that their stoves do not have a sealed combustion system option.

about2build

:eek: oh no....thats not what I was told. Then with quite a bit of emergency can anyone suggest an insert stove back boiler 3kw to room 15k to rads with a room sealed option

sas

about2build wrote: »

:eek: oh no....thats not what I was told. Then with quite a bit of emergency can anyone suggest an insert stove back boiler 3kw to room 15k to rads with a room sealed option

The assumption in general is that with an external air supply option, that's all anyone wants.

What I put to them was this:
" Is the stove manufactured in such a way that the only combustion air possible to enter the combustion process is via the 4 inch air intake pipe"

The answer was no.

I think we may all be getting a little too hung up on this entire concept. My brother in law has a reasoanbly airtight house. It could be better than reasoanble but it was never tested. He did use all the correct materials and it is cheap to heat so I'll assume it's pretty good. His stove is not room sealed and has a 4 inch external air supply. He's had no issues with smoke entering the room due to negative pressure nor has he mentioned any noticeable heat losses due to the stove. They love it in fact.

For my own home if I go with a boiler stove down the line, I will have a CO monitor located correctly near the stove. I am already connecting my HRV to the smoke alarms i.e. system shutsdown if any of them trigger.

If I don't go with a boiler stove I will likely insist on a stove with a sealed combustion system. I just haven't found any boiler stove anywhere at all that clearly is a sealed combustion system.

The internet is full of experts (me for example) which will entirely wreck your head. Sometimes you just gotta go with what makes sense for you and be vigilant for CO etc.

about2build

Since your reply I have been on to boru stoves in Tipperary and he maintained that the standard 600i does not come room sealed but on request one can be built ... for an extra cost. I agree with all your points above and a co2 monitor is a must i would have thought and yes link the mvhr to smoke alarms is what i am doing

sas

about2build wrote: »

Since your reply I have been on to boru stoves in Tipperary and he maintained that the standard 600i does not come room sealed but on request one can be built ... for an extra cost. I agree with all your points above and a co2 monitor is a must i would have thought and yes link the mvhr to smoke alarms is what i am doing

Someone from Boru rang me because I'd shown interest while in my local builders providers. They had passed on my details to him.

The guy I spoke to was potentially only a salesman. He didn't even know what I was talking about. Having said that, you've heard differently directly from them so I can't dispute that.

Good luck with it.

Tifosi

fclauson wrote: »

this is a big and often unaddressed problem - and you will see other posts from me asking fro MVHR "experts" of which I can find none

I am now working with a couple of UK companies

there are suggesting fire valves in both the sitting/stove room, the kitchen and if I go for an internal heat source other than a HP then in the room which contains that too (e.g. oil burner or gas)

they are also suggesting both supply and extract in the stove room for two reason
1 - so that you can (very slowly due to air volumes) spread the heat around the house
2 - create no negative or positive pressure in the stove room so that when you open the door no smoke/ash gets sucked out the fire

they are also suggesting the system is connected to the fire alarm/smoke detector system so that it shuts down in the event of the alarm being triggerd - no point in feeding the fire/smoke into your bedrooms :mad:

the CO2 detector and humidity detector in the MVHR system will/can control the speed of extract (house empty slows down / big party and lots of gossip system speeds up)

Just on the recommendation from the vendors are they suggesting fire or smoke dampers(values) fire dampers usually have fusible links and smoke, motorised values. Both usually required access, if a fusible link goes then you have bigger worries than just replacing the link.

about2build

Cheers sas. Ya its worth checking these things out.....the old saying measure twice cut once...:)

fclauson

Tifosi wrote: »

Just on the recommendation from the vendors are they suggesting fire or smoke dampers(values) fire dampers usually have fusible links and smoke, motorised values. Both usually required access, if a fusible link goes then you have bigger worries than just replacing the link.

I AM NOT EXPERT - THIS IS JUST ADIVCE I RECIVED

The fire valves are one shot affairs - i.e. in th event the "melt" and close then you have to get a new one - google "FIRE RATED EXTRACT VALVES FOR MVHR"

On "Room sealed" there bascally is no such stove if it has an opening door because the manufacture cannot gurentee that once installed that the ribbon seal around the door which stays in tact during normal operations.

Going back to the advice I received - I was refered to table 1 section 2.2 of Part J
Solid fuel burning A ventilation opening (or openings) with open appliance a total free area of at least 50% of the appliance throat opening area (of which at least 6500 mm2 is permanent ventilation) shall be provided. For description and dimensions of “throat”, see BS 8303: Part 1:1994).

So you need a duct which gives 6500 mm2 FREE AIR (i.e size your duct and then when you put vent a grill on the outside of the build make sure you still have the required FREE AIR measurement )

Hope that helps

isaos

Hello, Sorry for jumping in with a question only related to smells: The old 1996 Stanley oil fired boiler range we have in the old stone cottage (not air-tight!) we just bought is working fine, no CO2, 5 radiators. It has been serviced recently but there is a real bad smell of oil when the hot water has been switched on. We can't see any leaks, but the pipes go through a 4ft gable wall. Any idea of what we can do about that?
Thanks!

sas

fclauson wrote: »

I AM NOT EXPERT - THIS IS JUST ADIVCE I RECIVED

The fire valves are one shot affairs - i.e. in th event the "melt" and close then you have to get a new one - google "FIRE RATED EXTRACT VALVES FOR MVHR"

If you have your hrv connected to smoke/heat detector systems then the hrv will shutoff before these fire valves melt.

Are these an additional measure in case this doesn't happen or are there concerns with fire travelling the ductwork even if the hrv is off?

fclauson

sas wrote: »

If you have your hrv connected to smoke/heat detector systems then the hrv will shutoff before these fire valves melt.

Are these an additional measure in case this doesn't happen or are there concerns with fire travelling the ductwork even if the hrv is off?

I think so - but i depends - think of your duct work as a flue on an incinarator or BBQ - if there is any form of "draw" or "suck" through the pipe work then the smoke (and hence the heat and the fire) will spread through it - closing off that oppotunity has to be a good idea.

SAS - I know you have galv ducting - this will help as galv does not melt or burn too easy.

Just on the Galv vs PVC
Galv

• robust
• strong
• can cause "hum" as the air is spun down the duct by the twists of the duct
• harder to install
• might rust on bathroom extracts if you don't get condensation issues managed corectly

PVC

• easy to install
• generally viewed as quieter
• melts in a fire
• do you want to breath air that came through PVC for the rest of your life

muffler

isaos wrote: »

Hello, Sorry for jumping in with a question only related to smells: The old 1996 Stanley oil fired boiler range we have in the old stone cottage (not air-tight!) we just bought is working fine, no CO2, 5 radiators. It has been serviced recently but there is a real bad smell of oil when the hot water has been switched on. We can't see any leaks, but the pipes go through a 4ft gable wall. Any idea of what we can do about that?
Thanks!

isaos, You would be better off asking this in the Plumbing and Heating forum. Thanks

rodzer

Hello, we have a reasoanbly airtight house, test result 3. We did use a lot of the right materials and it is cheap to heat. Our stove may not be certified as "room sealed" but who cares? We love it, it's got an external air kit and burns for ages compared to an open fire. We don't have the fire dampers, fusable links mentioned above on our mvhr but maybe they can be retro fitted anyway? By the way, breathing air coming through PVC for the rest of my life doesn't bother me one bit.

paddym3

can a room sealed stove use a normal block built chimney. i am building a timber frame air tight house but want to use normal block chimney as easier to finish the capping externally and bit safer then having the flue any where near the timber kit

BryanF

Paddy it's all about the external air supply, then picking a stove that is actually room sealed, the choice of material you put around it is up to you. Choosing block is upto you. These stoves are still specialist items with many sales people still full of .... When it comes to 'fully' room sealed ' suitable' for Mvhr air-tight homes

sas

There is one issue I've heard of which goes a little something like this...

Basically the newer stoves are pretty efficient i.e. you lose less heat up the chimney.

The issue with this is that the flue gases need heat to rise and escape.

You need a pretty well insulated flue in this case to ensure that heat isn't lost by flue gases as they rise to outside. The worst risk with this is that you get a downdraft effect which is both dangerous from CO point of view but also damn unpleasant in the room i.e. smells.

However, I wouldn't for a second suggest a metal flue. They have limited life span, certainly vastly inferior to a good quality masonry equivalent.

In my case I bought flue liners made from pumice and the fill for around the liners is light weight agregate. The fill actually looks and feels like chocolate breakfast cereal. These are insulating and should help me avoid any issues.

However, I've no stove yet so can't comment if mine works or not.

There are masonry chimney systems that come with mineral wool type jackets to wrap around the flues which would also be good. They aren't cheap though.

paddym3

@bryanf i have a 150 mm external air supply for each stove and aware of the thernal bridge but block is finished and can with stand the heat as a flue lined system still hads cold bridge but not as much alos timber must be a min of 50mm from it so ost space any way.
must pm you

at sas
ys ihave seen the aggregate you on about it very light and hold heat well i am still toying with using standard clay lineers nad maybe a flue internal but not sure how or would it work or is it money wasted

Gasket

Hi All,
I'm new to the whole airtightness thing. I'm in the process of a new build (block construction, airtight MHRV) the floorslab is going in next week & i'm trying to figure out how to lay the air supply pipe for a future room sealed stove. One fireplace is on an outside wall but the other isn't. I'm told i need a minimum 100mm pipe to feed the stove but does anyone have any advice on how the pipe is carried up above ground level on the outside?

As far as i can see the only way will be to put a grille on the outside wall, then carry the 100m pipe down through the cavity, into the floor slab & then up in the back corner of the fireplace. Is there any issues with this, ie fire spreading to the pumped cavity insulation?

I've been told to slope the pipe & then put some holes at the lowest point, to drain off any condensate, but is it not encased in concrete?
Hopefully somebody has experienced this dilema before & can advise me?
Thanks

heavydawson

Gasket wrote: »

Hi All,
I'm new to the whole airtightness thing. I'm in the process of a new build (block construction, airtight MHRV) the floorslab is going in next week & i'm trying to figure out how to lay the air supply pipe for a future room sealed stove. One fireplace is on an outside wall but the other isn't. I'm told i need a minimum 100mm pipe to feed the stove but does anyone have any advice on how the pipe is carried up above ground level on the outside?

As far as i can see the only way will be to put a grille on the outside wall, then carry the 100m pipe down through the cavity, into the floor slab & then up in the back corner of the fireplace. Is there any issues with this, ie fire spreading to the pumped cavity insulation?

I've been told to slope the pipe & then put some holes at the lowest point, to drain off any condensate, but is it not encased in concrete?
Hopefully somebody has experienced this dilema before & can advise me?
Thanks

Hey Gasket,
I'm in a similar situation. I really don't want to break the insulation around the house by having a 4" pipe running through it, even if it's only for a short run. To that end, I'm running the pipe all the way out under the footpath, underneath the driveway, and having it emerge up through our lawn. I don't believe condensate should be an issue because you're not sending warm air through the pipe. I don't know exactly how high I'll need to bring the pipe up from the lawn (possibly 1ft), but I know I'll need a suitable cap to prevent rainfall into it, and also some sort of cowl that'll stop vermin getting in (if the height doesn't already solve it).

Because the pipe will be away from the house by about 7-10 meters, I'm not sure I need to tee it to negate the air pressure issues. It's effectively out in the open and shouldn't be subject to the compression/suction effect on varying sides of the house. I'm open to others opinions on this matter.