UKC

Having always had a feeling that any particulates going up my chimney can't be good for general air quality, I've been pleased to come across particulate filters online, which go on top of your chimney, which seem like a great idea, and an even greater idea on reading a paper from Denmark talking about the benefits which would occur if they were adopted nation wide.

Does anybody use one, and would they recommend theirs, or have the found any drawbacks with them? It strikes me that the need to clean them or have them cleaned each year could be a good reminder to have the flue cleaned as well, which wouldn't be a bad thing.

Many thanks.

Tim

In reply to Timmd:

I think you will find that your house insurance expects you to have your flue cleaned every 6 months by a professional (member of the approved association). If it does, and you don't it could affect any future claims. Take care everyone!

In reply to johncook:
Every six months seems oddly frequent when it's not used for 9 (?) months of the year, but I'll keep it in mind and investigate.

(joke) I wonder if I could find a friendly professional who I could give a tenner to for pretending they'd cleaned it?

In reply to Timmd:




This guy is excellent, proper cockney gezzer youtube.com/watch?v=k_mpaF5-SlU&

In reply to Timmd:
Were you looking at this system? http://www.poujoulat.co.uk/catalogues/domestic/Leaflet_top_clean_PF_2014.pd...

I note that the system doesn't operate until the flue gases are at the optimum temperature, which probably means once the stove is burning good and hot and clean, yet most of the pollution happens during lighting while combustion temperatures are still low. For an electrostatic system to work the flue gases would have to be dry, not moist as at the beginning of the lighting cycle.

The voltage at the electrode is 30 kV. I'm not sure I'd want that up my chimney!

The flyer says: "The number of particles will be significantly reduced by using a modern wood burning appliance combined with good quality fuel, appropriate chimney and by lighting the stove correctly." This is true and I note that the flyer doesn't really make a claim for efficiency, it just says "up to" 92 percent of particles of a certain size.

Finally what about the cost? It's not something you can just retro-fit to your chimney pot. You have to buy the whole system and will that fit down your chimney?

Seems to me that buying one of these will make you feel virtuous but make zero difference to pollution. In any case the pollution from domestic stoves is a tiny fraction of the pollution from other sources, especially road vehicles and aircraft.

In reply to Rigid Raider:
Yes it was, there's another company/site, too. I gather you can retro fit them according to their website, I'll have a look for the info..

I'm thinking one would probably only really know if it made any difference once it came to cleaning it each summer, with any kind of difference being a positive thing it seems to me, with stove becoming more popular it all add up.

I'm towards the edge of the Peak, so my immediate air is pretty clean, but the prevailing winds would be blowing anything emitted across the city.

In reply to Timmd:

A buddy of mine installs them, both the catalytic and electrostatic ones, €1500 upwards. The newer emissions regs in Germany mean you have to install one in older stoves or it will be shut down this year. BUT hardly anyone installs them because in general it is cheaper to change the stove instead to one which conforms and save money on fuel as it will burn more efficiently anyway.
Particulates from wood-fired heating is a real problem in Germany as they are so widespread, they pump out 24,000 tons a year which is over a third that is produced by transport of all kinds. If you´re unfortunate enough to live in an inversion-prone place it isn´t just of academic interest!

In reply to jimtitt:
I think my stove was bought within the past 2 years. My home is at the top of a hill with clean air, but the winds blow stuff towards the east across Sheffield, with the city centre and (generally) poorer homes being lower down and further east, so looking into getting a filter just seems like the decent thing to do really.

Sheffield (in case you don't know) is built upon and surrounded by seven hills, so the centre can get pretty bad, and cycling about the city has demonstrated to me how variable the air quality can be, the difference can be stark. If you cycle out to the Peak and look back towards the city on a clear you can see a brown layer of cloud/dirty air hanging over the city.

I've possibly just affected some house prices in Sheffield by writing this.

In reply to Rigid Raider:

Here you go, the Top Clean can be fitted to an existed chimney top apparently.

http://www.poujoulat.co.uk/catalogues/domestic/Leaflet_top_clean_PF_2014.pd...

In reply to Rigid Raider:


Aye, I'd want an insulated section in my flue if I was going to have one of these things.

In reply to Lusk:
It strikes me that there probably wouldn't be a company selling such a product in the EU/UK if they'd not thought about and addressed the possibility of electrocution.

In reply to Timmd:


One can never be to careful with high voltage electrostatics... Especially when in a hard to service location that's subject to significant temperature cycling and partially exposed to the elements.

Personally I'd save the money and put it towards my rooftop-solar or electric vehicle saving pots; these will undoubtedly make more difference to my net air pollution - as an occasional user of a modern stove with good fuel but regular user of grid power and fossil cars. Unlike the precipitator they'll also reduce my carbon dioxide output.

In reply to wintertree:

I get all that, but still, it's generally a key part of developing a product that these kinds of things are considered. A relative is an engineering professor (now retired), and through him I get the impression that it takes a lot for a product to able to sold around the world, from the different companies he's visited and then talked about what they do, in talking about the process of things being developed.

I can only imagine that the same applies to anything electrical too, if it's being sold in the EU?

In a friendly way, I think I'm more inclined to trust the regulatory framework than alarmed posters on UKC.

In reply to Timmd:
Not alarmed, just slightly tongue in cheek.
Mind you, there are so many cowboys out there who've done a five week course in Electrical Installation and then think they can call themselves Electricians, whose work is absolutely appalling, that's where your real danger occurs. I'd be fitting one myself.

Also, it's dumping all the soot in one place, your flue will getting blocked every few weeks!

In reply to Timmd:

I'm ready to be convinced but I fail to see how an electrostatic charge can remove significant amounts of particles from a fast-rising stream of hot gases blasting past. If I bought one it would be as a virtual sticking plaster to assuage my guilt over my stove use.

I installed a 20 tube solar water heater on my roof about 8 years ago; it cost me £700 DIY and I reckon it saves about £60 a year in gas costs - nothing in the grand scheme of things but it sure as hell makes me feel virtuous.

One other point - the box of tricks attached to the flue in the illustration on the website I linked has to go outside the house?

In reply to Timmd:


You say that, but go and make some measurement on the metal frames of rooftop solar installations that use transformerless inverters, especially on a wet day.

Some of them are shocking I tell you.

Then throw in the wild card of the amount of stuff being sold by certain online matketplaces that comes from far away and apparently has never seen an EU test and is, even on a cursory visual inspection, never going to be safety compliant...

In reply to Rigid Raider:

It does go outside the house, I think we probably both shared the same link but focused on different pages?

There's a 'for renovation' page which features the Top Clean which can be fitted to existing chimneys, which seems to have an example picture with a company supplied liner, with a liner already in place, and an unlined chimney as well.

In reply to wintertree:


I'll be sure to investigate Poujoulat and other manufacturers of electrostatic filters very carefully and read up on their products and who installs them.

In reply to Rigid Raider:

Electrostatic precipitators are well-established technology for cleaning gas streams of particulate and volatile contaminants before the air is emitted to atmosphere. I've only ever been involved with industrial scale ones so can't really comment on how they'd go on a domestic chimney but they're certainly able to remove a high proportion of nasties from hot gas streams.

In reply to AdrianC:

Yeah; I remember a school trip to British Steel's Stocksbridge special steels works (1978, probably), and they had precipitators over the furnaces. They had a truck sitting under the filter output, and I think they filled six 40-ton trucks per day. It went back into the furnace, as most of the particulate was metal and ore dust.

In reply to Timmd:




There are stoves with no emission certification and those with, as far as I know the UK has no controls and no certification system but if it is from a reputable manufacturer it will conform either to the EU standards or the German ones (BImSchV) which will tell you how dirty it is.
I went to Sheffield, once

In reply to jimtitt:


In the UK DEFRA certify stoves for wood burning in 'smokeless zones' (very patchy on a street by street basis 1950s, possibly 60s anti smog legislation). Basically approved stoves have to burn hot and clean with good secondary/tertiary burn and they cannot be completely shut down to smoulder. They also tend to be smaller stoves in the 5kW bracket. The alternative is certified smokeless fuel in a non certified stove.

Timmd: While the aim is laudable I suspect the money might be better spent elsewhere.
jk

In reply to jkarran:


Have you heard the news this week about wood burning stoves adding to London air pollution? You don't know how much their cheapest filter is.

In reply to Rigid Raider:


I don't know about on a flue but one of my customers has one on the intake to his blowers, the twin elements are about 18 inch square each made up of thin plates with about 1/6th between them.
60,000 cubic meters per hour flows through them and in to the blowers and when I service the blowers they are always pretty clean inside.
Not quite as clean as a traditional membrane filter but clean enough and unlike membrane filters these have never blocked, once a year I remove the elements and vac out the bits of dead fly and it's good to go again.

In reply to Timmd:
New Scientist this week says a study suggests these particulates can enter the room in which the stove is being used, especially when it is first lit. ( Even with a well installed stove.) The effect may be up there with smoking cigarettes.
Yikes!

In reply to wintertree:


What like car engines?

In reply to Rigid Raider:


They've been using them for years, on a slightly larger scale, on industrial flues. There are proven technology and relatively safe, if installed correctly.

One of my first jobs as an apprentice was to re-furbish an electrostatic precipitator, it was about 30 ft high by 20ft square. They used wooden panels with a lead "wire" to carry the voltage.

In reply to krikoman:


What's your point, caller?

I treat electronic ignition systems with a healthy degree of caution. They're also designed, factory fitted and almost never modified in a safety conscious industry. Quite different to an aftermarket product being installed on something designed without it in mind.