Why insulate

[Ferdinand]

31 minutes ago, Onoff said:

 

Isn't he aiming to increase revenue from Council Tax by allowing Londoners to build willy nilly in their gardens etc? Should be a lot easier to get PP in London now as councils will have to hit quotas. The cynic in me says the housing need is in part being met by the "beds in sheds" landlords and his plans will legitimise this to some extent with retrospective approvals.

 

Have not seen that one, but beds with sheds will not get widespread post-approval, unless they are if a decent quality. Plenty of regs can be used to close them down, and the issue is too high profile to fiddle imo. There would be hell to pay.

 

He did promise to plant 2 million trees in London, but that seems to have evaporated.

[joe90]

Well I have lived in a caravan for about 10months and grew to hate it ( I should have put a wbs in it like pro Dave). My build is block/brick with 200mm insulation and 300mm in the warm roof. Double glazing which is within a knats whisker of triple glazing but great airtightness ?(I hope), we have fitted a wood burner, room sealed, and latest design for efficiency, yes we may get too warm at times but I don’t mind that for the aesthetics . We are very rural and won’t rely on the stove for heat 24/7 but for cosy evenings. I hate a living room without a focal point.

[ProDave]

6 hours ago, TerryE said:

1. You need the core of the burn / or exhaust gasses to get up to a minimum of ~1,000°C (yes that is one thousand).  Any less and the products of combustion don't break down properly and your stove will  produce more nasty products of combustion than your typical diesel car.  Stove manufacturers like to put a nice glass window onto this core.  (I did a quick search and not even the continental suppliers like Jotul and Nordica no longer seem to offer small fully closed stoves.).  This then emits a lot of radiant heat means that ...
2. You find it hard to modulate your stove down to a minimum of say 2½ kW output, that's 60 kWh a day, which in my case is roughly 4× the amount of top-up heat that I need in winter months.  This heat is produced in one room, so even with a properly insulated house this is far more than a single room can take, unless you have a very large open plan area and even then you may need to actively redistribute this heat around the house.

.....   Any small manually fed stove will not have enough bulk capacity to keep enough supply in the burn chamber to run overnight and still be alive in the morning, so you will invariably need to relight the stove every day.  (Butane or Propane gas poker's highly recommended for this, BTW.)   

You have yo adjust your mindset.  Forget wanting to keep the stove in overnight, and forget a long burn.

 

If your house needs 15 KWh per day, then a s,all 3KW stove running at full tilt, nice and hot for a few hours, then let it go out, will do that. and being a well inulated house it won't cool down much until you do the same next day, or whenever it has cooled down to need some more heat input.

 

I think people talk of a stove overheating a well insulated house must be trying to run the thing for too long.  There is certainly no need to run it long and definitely no need o keep it going overnight.

[MikeSharp01]

On 26/10/2017 at 19:21, JSHarris said:

In very rough terms, a conventional wood burning stove is around 100 times more harmful than a diesel car, so you can roughly equate having one running to having around 100 diesel cars parked outside with their engines running.

Can you point to the evidence for this as it stopped me putting a light to the Woodburner this morning in favour of letting the LPG fueled central heating stay running. Sadly I cannot do the test as I only have two diesel cars

[MikeSharp01]

9 minutes ago, ProDave said:

Any small manually fed stove will not have enough bulk capacity to keep enough supply in the burn chamber to run overnight

Don't agree fully Dave as our little villager if built up at night and then fully damped it stays burning, albeit at a very low output, and will reignite in the morning when you open the dampers. 

[Jeremy Harris]

12 minutes ago, MikeSharp01 said:

Can you point to the evidence for this as it stopped me putting a light to the Woodburner this morning in favour of letting the LPG fueled central heating stay running. Sadly I cannot do the test as I only have two diesel cars

 

 

It was from data gathered on particulate and other harmful emissions as a part of the Australian wood burner ban, IIRC.  I didn't keep links to it but will try and pin down some definitive sources later.

 

As an aside, our MVHR has had to be turned off three times over the past week.  The combination of cold, still, nights has meant our valley has filled with woodsmoke from open fire and wood burning stoves.  Leaving the MVHR on resulted in the whole house being filled with smoke..................

[joe90]

Although I have a wood stove I do agree that certain locations can be anti social for these, towns, valleys etc but impossible to legislate against. 

[Oz07]

Can mhvr not be modded to filter smoke out?

[Pocster]

On 26/10/2017 at 19:21, Onoff said:

On some level I agree with your sentiments but...

 

For a start wait until you're I dunno, in your 70s (tin hat on ) or your partner / child(ren) needs the sort of care that means time to go and chop wood just isn't there...

 

I absolutely DREAD the day, with my crap pension forecast, when I'm old and in this house still with leaks and high fuel bills.

 

I LOVE the idea of sitting somewhere dry, warm and safe looking out of big 3G glazing and knowing a big bill for (in my case) oil won't be landing on the mat. 

 

You pay for insulation ONCE, you'll be paying for "fuel" even if "free" in other ways even if it's just the labour to chop it or the back boiler burning out periodically.

 

Anyway, you're ALL wrong. You should be going UNDERGROUND and letting the mass of earth and stable year round temperatures work for you! 

 

Tin hat on too!

 

Now then ! Underground is the way to go !!!! ?

[joe90]

1 minute ago, pocster said:

Now then ! Underground is the way to go !!!! ?

 

Not with my water table ?‍♀️

[Pocster]

2 minutes ago, joe90 said:

 

Not with my water table ?‍♀️

Does make it somewhat tricky 

we will have a log burning fire a) for heat and b) it provides swmbo with a ‘happy’ factor .

tbh it’s worth it just to comply with b) .....

chopping wood is good excercise! Man up you lot ?

[TerryE]

1 hour ago, ProDave said:

If your house needs 15 KWh per day, then a s,all 3KW stove running at full tilt, nice and hot for a few hours, then let it go out, will do that. and being a well insulated house it won't cool down much until you do the same next day, or whenever it has cooled down to need some more heat input.

Dave, that is exactly what we do in Alonissos. But you missed highlighting my other part of the formula, which is that you need to ensure that you can rapidly spread the heat around the house, otherwise the room that the stove is in will just become a dry sauna.

 

We bought one of these fancy new Dyson fans for the living room in our new house for instant quick boost, should we need it. After 30 mins, the room is starting to get too warm -- we only have the internal door to the rest of house and lots of acoustic insulation in the internal walls and ceiling (another BReg requirement), so if you want one you must adapt your house design accordingly, e.g. open plan living room and stairs or fan-assisted ducting into the hall and other downstairs rooms).

 

The reason that most wood stoves are so polluting is that people burn them too cool.  The efficiency is crap and the nasties in the exhaust too great.  You really need a core temp approaching 1K °C to eliminate these.  So using your own collected / cut firewood is a no-no unless you know how to stack and prepare it and are willing to wait at least 2 years and preferably 3 before you use it.

[Ferdinand]

1 hour ago, JSHarris said:

 

 

It was from data gathered on particulate and other harmful emissions as a part of the Australian wood burner ban, IIRC.  I didn't keep links to it but will try and pin down some definitive sources later.

 

As an aside, our MVHR has had to be turned off three times over the past week.  The combination of cold, still, nights has meant our valley has filled with woodsmoke from open fire and wood burning stoves.  Leaving the MVHR on resulted in the whole house being filled with smoke..................

 

So quite an effective filter for the outside environment then .

[Jeremy Harris]

1 hour ago, Oz07 said:

Can mhvr not be modded to filter smoke out?

 

 

Sadly not.  You can filter out some of the harmful  particulates, but the cost of the very fine (sub 2.5µ) filter, plus it's size and the need to very regularly clean it or replace it, would be very high.  Even that would not remove the smell, which is the main nuisance factor.  AFAIK, no one offers filters that are this fine, the finest intake filters are currently a lot coarser that this and intended to filter out pollen, which is typically around 10µ to 100µ in diameter.  I believe the current finest filters aim to catch only some of the 10µ stuff, using the inherent "stickiness" that pollen has.  Typical woodsmoke and car exhaust PM_2.5s are not very sticky, so need fine filters.

Edited December 2, 2017 by JSHarris
error in pollen particle size quoted

[Jeremy Harris]

2 hours ago, MikeSharp01 said:

Can you point to the evidence for this as it stopped me putting a light to the Woodburner this morning in favour of letting the LPG fueled central heating stay running. Sadly I cannot do the test as I only have two diesel cars

 

 

I've had a quick scan, some data is reliable, some far less so, as it's from pressure groups.  Taking the least reliable first.  When Australia acted to place bans on wood stoves in first one area, and now, I believe, other areas, this followed studies that showed a higher incidence of disease related to air pollution in those areas.  This pressure group (so treat the data with due caution) have made some comparisons that are on the high side, such as suggesting that wood stoves emit around 1000 times more PM2.5s than car exhaust (personally I'd question that):

 

http://woodsmoke.3sc.net/health

 

The Launceston study ( http://menzies.utas.edu.au/news-and-events/media-releases/2013/reduction-in-air-pollution-from-wood-heaters-associated-with-reduced-risk-of-death ) is quite compelling, though, as it seems to show a pretty strong causal link between wood burning stoves and disease, high enough to be statistically relavant for sure.  As a cautionary note, the local environment there tended to produce higher levels of low level air pollution than areas with a different topology or weather patterns.

 

This abstract from the British Medical Journal is clearly written by someone who is anti-wood smoke, but nevertheless there are some snippets of decent data in there (pity you have to be a BMJ member to read the whole paper: http://www.bmj.com/content/350/bmj.h2757/rr-0    One quote from that has clearly been chosen to stand out:

 

Quote

Log-burning stoves permitted in smokeless zones emit more PM2.5 per year than 1,000 petrol cars, with estimated annual health costs of thousands of pounds per stove per year.

 

There's an interesting paper from Norway, all the more interesting as Norway has a long history of burning wood and has, along with other Scandinavian countries, done a fair bit to improve the way stoves combust more efficiently, and in ways that produce less pollution (basically it comes from the the rocket stove principle, make the burn as hot as possible and never restrict the air supply to reduce heat output ):

 

http://www.miljodirektoratet.no/old/klif/nyheter/dokumenter/25042013(PM emission factors wood stoves_Rapport_Final_64-65).pdf

Edited December 2, 2017 by JSHarris
typo

[TerryE]

That Norwegian paper is an interesting, albeit heavy read.

[Bitpipe]

On 26/10/2017 at 19:21, Onoff said:

 

Anyway, you're ALL wrong. You should be going UNDERGROUND and letting the mass of earth and stable year round temperatures work for you! 

 

 

Yup, our basement has no heating and is perfectly comfortable all year round.

 

My other half took some convincing to give up on a wbs and I offered the compromise of an ethanol 'bio' fire but even they chuck out 3KW.

 

 

[Bitpipe]

On 26/10/2017 at 20:11, Onoff said:

 

You know it makes sense! 

 

Put the saving towards a Raspberry Pi and a small (or large) flat screen set in a fire place and indpendent of the telly displaying the log fire of your choice!

 

...you'll also be able to play Space Invaders on it!

 

I actually downloaded a log fire app on the amazon fire stick for last xmas, really just as a joke. The weird thing is that it does give the illusion of warmth..

[Jeremy Harris]

39 minutes ago, TerryE said:

That Norwegian paper is an interesting, albeit heavy read.

 

 

It is, but perhaps of more relevance here is this UK paper:  https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/579200/Emissions_airpollutants_statisticalrelease_2016_final.pdf

 

This quote from it, regarding PM₁₀s and PM_2.5s is worth noting:

 

Quote

Emissions from road transport accounted for 14 per cent of PM₁₀ and 13 per cent of PM_2.5 in 2015 and is the third largest source after combustion in residential, public, commercial & agricultural sectors, and industrial processes.

 

The contribution from the category covering combustion in the residential, public, commercial & agricultural sectors has increased over recent years and peaked in 2013 at 51 kilotonnes PM₁₀ and 50 kilotonnes PM_2.5.  In 2014 there was reduced fuel demand in the domestic sector but consumption increased again in 2015 and estimated emissions from residential, public, commercial combustion were 48 kilotonnes for PM₁₀ and 47 kilotonnes for PM_2.5.

 

Most of the emissions from residential, public, commercial combustion in these last 3 years – 79 per cent for both pollutants - are from the use of wood as a domestic fuel.

 

 

Note the final sentence that I have highlighted...................

Edited December 2, 2017 by JSHarris

[ToughButterCup]

37 minutes ago, Bitpipe said:

I actually downloaded a log fire app on the amazon fire stick for last xmas, really just as a joke. The weird thing is that it does give the illusion of warmth..

 

Its not an illusion.

Put a glass of gin, ice and a slice in front of it, and it gets warmer. Same with a cold beer.

Gonna try a ready meal in front of it  next time Debbie is working late.

[Onoff]

I posed the question of MVHR sucking in "smoke" a while back.

 

I wonder if you could bring in outdide air via say a water bath to filter the particulates?

 

 

More the worry is drowning in an airtight building if a pipe bursts and you sleep on a futon! Presumably it'd only ever get as high as the lowest wc?

[Jeremy Harris]

You could almost certainly use some form of water trap/filter, but it would need a fair bit of power to drive it.  The suction on the intake side of an MVHR is very small, not enough to bubble air through water by a long way.  A water spray mist curtain might well wash out much of the stuff, but again would need a lot of power, create a lot of waste water and increase the humidity of the incoming air.

 

Ideally, some sort of activated carbon filter might work best, although again there would be the major problem of regenerating the carbon at regular intervals.  Ozone would reactivate a carbon filter pretty quickly, I think, so some sort of reciprocating arrangement, or perhaps a rotary arrangement as you have in commercial air handling system heat exchangers, might work.  The idea would be to have one filter in use, and periodically have it change over with another filter that was "backwashed" out with air and ozone (air to blow out the particulates, ozone to oxidise out all the volatile smelly stuff).  Filter regeneration probably wouldn't take more than a few minutes, and it should be possible to blow the trapped particulates down into a water tank, where they could be trapped.  The water tank would have to be cleaned and drained periodically, but it could probably be made to work.

 

If you weren't too bothered by the severe health risk from the woodsmoke particulates, but just wanted to get rid of the smell of from the volatiles being sucked in, then some way of detecting them and injecting a very low dose of ozone, as required, would almost certainly remove any smell.  This sort of system is very effective.  For the past few years we've had a small, battery operated, ozone generator in the fridge.  It periodically releases a very tiny amount of ozone, barely enough to detect, yet is extremely good at keeping the odours from things like smelly cheese undetectable (as long as it stays in the fridge).  Similarly, when I was playing around making the ozone generator for our water system, I tried one inside the house.  Even modest amounts of ozone blown into the house made it unbearable to stay in for more than a few seconds, but was extremely effective at removing all lingering odours.  It works by being an extremely powerful oxidant, that preferentially oxidises volatile organic compounds that we detect as bad smells,  It does this at concentrations that are very low, in terms of health risk, and also far lower than the sort of concentration needed to bleach things (ozone is a much more powerful oxidising agent than chlorine).

[Onoff]

At work we would leave an aerosol can lid in the fridge. Half filled with instant coffee granules it seemed to take up most smells.

[Onoff]

That's got be a risk albeit a small one if somebody "had it in for you" and decided to feed something nasty in via the MVHR intake. 

Edited December 2, 2017 by Onoff

[Declan52]

5 hours ago, MikeSharp01 said:

Don't agree fully Dave as our little villager if built up at night and then fully damped it stays burning, albeit at a very low output, and will reignite in the morning when you open the dampers. 

Same here if I fill mine with good quality coal. All it needs is raked out and the dampers opened up and it will catch again.