Garald Posted January 2, 2023 Share Posted January 2, 2023 (Current state of the house renovation saga: I'm having the attic properly insulated. The heat loss calculation sheet is now giving 5.7kW as the total loss when it's -2C outside - of course that does not take into account some imperfections inherent to any renovation. At any rate, given that heat-pump will also be used for hot water, the choice is now between a 7kW Saunier-Duval (i.e. Vaillant) and a 8kW Saunier-Duval, with the architect and one of the installers leaning towards the latter option. (Of course one should not be too keen to overdimension, but perhaps it's no tragedy either: the heat pump has an inverter, so it should be reasonably efficient even when running well under capacity, no?) I'm being advised by nearly everybody to compute heat losses and radiator sizes for -2C. (I'm in the Paris area; consider it to be very much like London in terms of temperatures, at least during the winter.) Even allowing a safety margin, this leaves open the question of what to do on those rare occasions when temperature go well under -7C or -10C, say. The place has two working chimneys - they haven't been used in the last few years, but the previous estimates asked for estimates from a chimney-maintenance business at my request, and the verdict is that one of the chimneys - the one in the house's largest room, the ilbrary - would be cheap and easy to clean properly. Of course open chimneys are very inefficient and also interior air quality, so the question is really whether to buy a modern, high-performance wood stove to install inside the chimney. Now, I've read that a wood-stove is in general a terrible idea because of particle emissions. But what about using it only during cold waves, as a backup mechanism? (This was actually suggested by a German heat-pump book I got.) Or if the heat-pump ever breaks down? And how eco-friendly (or not-utterly-eco-murderous) are wood stoves now, really? If I read information such as: Emission de CO (en %) 0.12 Particules fines (en mg/Nm³, @13% O2) 23 - is that good, bad, terrible? Link to comment Share on other sites More sharing options...
Iceverge Posted January 2, 2023 Share Posted January 2, 2023 2 hours ago, Garald said: Emission de CO (en %) 0.12 0.12% carbon monoxide is 1200ppm. Typical values in flue gas: Oil burners: 80 ppm - 150 ppm and Gas burners: 80 ppm - 100 ppm. 2 hours ago, Garald said: Particules fines (en mg/Nm³, @13% O2) 23 Typical values for an oil boiler might be 1.8 mg/Nm3 and 0 for gas boilers. The stated figure of 23 is lightly to be the optimal combustion conditions for the given stove. Highly difficult to achieve in real life. Look at the below graph to see how bad it gets if you are a bit off with your burning. Over a hundred times worse if you throttle the fire. Note the exponential scale. Buy a couple of €10 electric heaters and hide them away for the unusual cold day if you're concerned about polluting the air. Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 3 hours ago, Iceverge said: 0.12% carbon monoxide is 1200ppm. Typical values in flue gas: Oil burners: 80 ppm - 150 ppm and Gas burners: 80 ppm - 100 ppm. Typical values for an oil boiler might be 1.8 mg/Nm3 and 0 for gas boilers. The stated figure of 23 is lightly to be the optimal combustion conditions for the given stove. Highly difficult to achieve in real life. Look at the below graph to see how bad it gets if you are a bit off with your burning. Over a hundred times worse if you throttle the fire. That's pretty shocking. 3 hours ago, Iceverge said: Buy a couple of €10 electric heaters and hide them away for the unusual cold day if you're concerned about polluting the air. Anything useful I might do with the fireplaces? Link to comment Share on other sites More sharing options...
Onoff Posted January 2, 2023 Share Posted January 2, 2023 Burn stuff, fire good. 1 Link to comment Share on other sites More sharing options...
MikeSharp01 Posted January 2, 2023 Share Posted January 2, 2023 6 hours ago, Iceverge said: Over a hundred times worse if you throttle the fire. As in keep the oxygen input low and burn slowley - so letting it rip, as in force feed / allow free running oxygen, is a good / better thing? Link to comment Share on other sites More sharing options...
jfb Posted January 2, 2023 Share Posted January 2, 2023 7 minutes ago, MikeSharp01 said: As in keep the oxygen input low and burn slowley - so letting it rip, as in force feed / allow free running oxygen, is a good / better thing? Yes Link to comment Share on other sites More sharing options...
ProDave Posted January 2, 2023 Share Posted January 2, 2023 A lot of modern stoves, mine included, restrict how much you can restrict the air flow so it is impossible to throttle them down too much. They do this to meet the current emissions limits. While I love our stove, it's key advantage is free fuel. If you live in a city, and have no trees of your own, I would not have one. Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 17 minutes ago, ProDave said: While I love our stove, it's key advantage is free fuel. If you live in a city, and have no trees of your own, I would not have one. Plus, the problem here is not "I destroy the planet", but rather "I poison my neighbors and myself", so, no neighbors, no problem, no? All right, so - what do I do with my nice working fireplaces? More importantly: - What do I do if the heat pump fails? Ok, Ok, electric heaters obtained somewhere at the last minute. But: - what do I do during an electricity failure in the dead of winter? Link to comment Share on other sites More sharing options...
Thedreamer Posted January 2, 2023 Share Posted January 2, 2023 Do you not have access to cheap mains gas? I live in a rural environment off grid for gas and heat the house exclusively with wood (home grown trees). It works for me as it's very cheap (with UK government rebates my total electricity account is expected to be in credit by March). I have the set-up for doing this efficiently, tools and storage area. As it sounds like you will be burning very rarely I would block up your fireplace and put a decorative item there. If the electricity fails (and you don't have mains gas) my advice would be to wrap up warm and wait for it to be reconnected if you are in a urban area, then this is prioritised so should only be a short term disconnection. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2023 Share Posted January 2, 2023 18 minutes ago, Garald said: More importantly: - What do I do if the heat pump fails? Ok, Ok, electric heaters obtained somewhere at the last minute. But: - what do I do during an electricity failure in the dead of winter? Same as we did in the UK 50 years ago, wait till the power comes back on. In Paris, if something is broken, it is usual to riot. Get a gun. Just don't breath in the cordite fumes. The WHO has declared that there is no safe limit for particulates. https://www.who.int/teams/environment-climate-change-and-health/air-quality-and-health/health-impacts/types-of-pollutants This does not mean that we are all not breathing them in all the time, but adding to them is not a good idea. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2023 Share Posted January 2, 2023 3 minutes ago, Thedreamer said: home grown trees Does that stop the pollution and habitat destruction? If I grow my own tobacco, will it be acceptable to smoke it in a pub? Link to comment Share on other sites More sharing options...
ProDave Posted January 2, 2023 Share Posted January 2, 2023 2 minutes ago, SteamyTea said: Does that stop the pollution and habitat destruction? If I grow my own tobacco, will it be acceptable to smoke it in a pub? The point is those of us who have trees, you need to do something with the wood. Windfall, normal pruning, and shortly I will be dropping a dead tree. I suppose I could stack it all up to become a mess in my garden for woodlice to live in as it slowly rots and slowly releases it's carbon, or I could give it to someone else to burn. So instead I burn it myself. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2023 Share Posted January 2, 2023 1 minute ago, ProDave said: slowly rots and slowly releases it's carbon Or becomes new soil. There is a perpetual myth that any fallen timber rots down to CO2. Probably why the CO2 levels in the Amazon rain forest are chokingly high. Good job that all the ocean flora is collected up and stored safely before burning, would have to swim in carbonic acid otherwise. Link to comment Share on other sites More sharing options...
Thedreamer Posted January 2, 2023 Share Posted January 2, 2023 1 minute ago, SteamyTea said: Does that stop the pollution and habitat destruction? Very little pollution when burned efficiently. Actually burning trees in a sustainable way is fine. I don't collect my logs from a petrol station in a plastic netted bag of logs and burn in an irresponsible way. The logs and branches have been grown here and heat my family. No part of this process is wasted. The biochar/compost I have created as a side effect is being enjoyed by all. The sub soil is now full of activity, birds are loving the richness that I have created. 1 minute ago, SteamyTea said: If I grow my own tobacco, will it be acceptable to smoke it in a pub? It wouldn't really serve a purposes, but smoking outside in the beer garden would be fine. 2 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2023 Share Posted January 2, 2023 4 minutes ago, Thedreamer said: It wouldn't really serve a purposes, 4 minutes ago, Thedreamer said: enjoyed by all Link to comment Share on other sites More sharing options...
Thedreamer Posted January 2, 2023 Share Posted January 2, 2023 15 minutes ago, SteamyTea said: Or becomes new soil. There is a perpetual myth that any fallen timber rots down to CO2. Probably why the CO2 levels in the Amazon rain forest are chokingly high. The amazon has an eco system to cope with breaking down timber quickly. And the small areas that were cultivated by local people adopted a similar approach of building soil to what I mentioned earlier using organic matter and charcoal. In the UK our natural eco system has gone, with the removal of forested area. The UK has lost most of the rich humus that existed in the soil. The small patch around my house is being replaced to what may have existed previously. Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 1 hour ago, Thedreamer said: Do you not have access to cheap mains gas? We've already cut off the gas - someone from the gas company will come soon to take the meter. Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 There's also wood pellet burners, but those are very pricey, and so not even remotely an option for occasional usage - besides being electricity-dependent. Link to comment Share on other sites More sharing options...
Iceverge Posted January 2, 2023 Share Posted January 2, 2023 7 hours ago, Garald said: Anything useful I might do with the fireplaces? Maybe fill them with insulation. And cap them off. Otherwise I have always thought that a vertical service void would be very handy for wires, ducting etc. Cap the chimney off, block the fireplace and go from there. 3 hours ago, Garald said: what do I do during an electricity failure in the dead of winter? Buy a small gas or kerosene stove. This particular debate has been had a few times . Many are happy to live with the localised elevated particulate levels confident that they're not harming any neighbours. Scientifically there's no doubt as to the risks to health. Shame really, I quite like a nice fire. Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 14 minutes ago, Iceverge said: Buy a small gas or kerosene stove. Isn't kerosene great for accidental self-immolation (besides stinking up the place)? I think a neighbor of my grandmother's died like that. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2023 Share Posted January 2, 2023 (edited) 39 minutes ago, Iceverge said: Shame really, I quite like a nice fire. I am sure I would quite like heroin, not sure I should try it, I have seen what it has done to my neighbour. Edited January 2, 2023 by SteamyTea Link to comment Share on other sites More sharing options...
Iceverge Posted January 2, 2023 Share Posted January 2, 2023 12 minutes ago, Garald said: Isn't kerosene great for accidental self-immolation (besides stinking up the place)? I think a neighbor of my grandmother's died like that. That's a sad way to die. You can buy a 3kw bioethanol stove for about €1,000. Its another option. I would prefer the €10 fan heater to be honest but I'm tight! Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 26 minutes ago, Iceverge said: That's a sad way to die. Correct. My grandmother told it with more drama - she's no longer around to confirm the details (unsurprisingly given her birth year), so I would have to ask my mother for confirmation. Something about the burn victim managing to collect herself and handing over her children to her closest neighborhood friend, but nothing (or not enough) could be done for her, with medicine being what it was at the time and place. 26 minutes ago, Iceverge said: You can buy a 3kw bioethanol stove for about €1,000. Its another option. Right, but it wouldn't make sense to put it in a hearth, as opposed to the middle of the room, right? Or is it safer to put it in a hearth (even if it may be the least efficient choice)? 26 minutes ago, Iceverge said: I would prefer the €10 fan heater to be honest but I'm tight! Sure (note: I am also tight), that's both the option to have handy and the argument to convince the architect that one shouldn't base one's heat-loss computations on a -10 C outside temperature if one is in the Paris area. Thinking now in terms of what to have as a backup plan if the electricity system goes haywire (either in the neighborhood or at my place). Link to comment Share on other sites More sharing options...
Garald Posted January 2, 2023 Author Share Posted January 2, 2023 57 minutes ago, Iceverge said: You can buy a 3kw bioethanol stove for about €1,000. Its another option. It turns out one can get a bioethanol stove for much, much less (see, e.g., https://www.leroymerlin.fr/produits/chauffage-et-ventilation/poele-et-cheminee/cheminee-a-ethanol/poele-bio-ethanol-p.html). Perhaps that makes most sense, then? Can start a new thread. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 2, 2023 Share Posted January 2, 2023 Mousehole in Cornwall. 2700 miles of nothing to the west. Then this. This only shows 4, but counted 7 so far. At least these ones are visible. Link to comment Share on other sites More sharing options...
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