Cost of Logs vs. Briquettes

mmmmikey

I have been reviewing the cost of logs and briquettes for fuelling my wood stove prior to placing my next order and thought I would post details here in case it's of interest.


Based on online research as at Jan 2019 and buying in full pallets, RUF type compressed briquettes are available from £240 per pallet delivered, and assuming 5kWh per kg and 80% stove efficiency this works out at about 6p per usable kWh.


Kiln dried mixed hardwood logs from my local supplier cost £85 for a load of about 210kg delivered, and assuming 4.5kWh per kg and 80% stove efficiency this works out at about 11p per usable kWh. (Online prices based on buying large, stacked pallets works out at about the same).


So on paper the briquettes work out about 45% cheaper. Having bought a small quantity of briquettes and tested this, admittedly only over a few days, that seems about right in practice, although using a couple of regular logs to get a nice hot bed of ashes to get the fire started reduces the saving to about 40%.



The briquettes (in my stove) have the added advantages of a slower, more consistent burn, less smoke, no blackening of the glass and more attactive flames (noting that I have to run my stove at as low a temperature as I can to stop the room overheating). The only downside I am finding is that although there is less ash with the briquettes, the ash that is produced is fine and powdery and makes the room a bit more dusty.


Given that, as I understand it, the briquettes give out less particulates, this makes them a clear choice for me, and should save of the order of £200 per year.



Be interested to hear any comments anyone has on this.......

silverwhistle

Can't really help here as, in the true spirit of MSE, I scrounge all the wood I use. I follow the sound of chainsaws, grab pallets from my neighbour, take another neighbour's joinery off-cuts and generally ask people to keep an eye open..


I do use the occasional briquette for convenience and having a known quality/moisture level to get the right mix in the stove. I used to buy Verdos, but in their absence get the occasional pack from the cheapy supermarkets. The quality does vary, so if you've found one you're happy with I'd stick with it.

Exiled_Tyke

Interesting numbers. Thank you.

I'm also interested that Briquettes leave a powdery ash which is probably better for the chimney. A friend and I burn exactly the same wood (from his forest actually), which is seasoned with care! However I tend to burn relatively hot and therefore fast, while we are in the room in front of the fire. He on the other hand likes to keep the fire going all the time on a low heat. We both recently had our chimneys swept. Mine had good quality fine and dry ash whilst his was poorer quality and the sweep expressed concern that he needs to look after the chimney better. So I'd be careful about burning too slowly but if you have to briquettes appear to be the better way to go, from what you've said.

mmmmikey

Yes, good point, I'll get the chimney swept and see what it's like now, then swept again in a year or so to see what effect the briquettes have had. Been using these for a few days now and the numbers still stack up, but what I have found is that if I light the fire earlier in the afternoon by the time I've burned about 4 briquettes slowly I've got a heap of partly burned sawdust in the grate and eventually need to increase the heat to burn it off. I've also tried using an extruded heat log on top and full heat to get a really hot fire before bedtime which leaves a really clean grate in the morning. So a bit of management involved, but much more consistent and controllable than the mixed logs I was using. I suspect I'm going to end up with something like a ratio of 1 extruded heat log to every 4 briquettes, still a big saving over where I was and working very well alongside my storage heaters to heat the house where and when I want to.

zeupater

Hi

I've been following this for a few days & fail to understand how the costs mentioned can be considered good.

We buy around 3cubic metres (~2 tonnes) of hardwood (not mixed) at a time which is normally made up of Ash & Oak, occasionally with a little Beech mixed in ... it's all well seasoned, then chopped before at least a further 6months of further drying in barn storage ... when we take delivery it'll sit in our log-store for at least 3 months before it's used, but more often than not it'll sit in there for at least a year .... the last load cost £165 delivered & it's relatively cheaper if you can take/store larger loads .... !!!!

It may be neater or more convenient to have small loads of logs delivered in crates or builder's bags than having to cope with a tipped load, but boy do you pay for the privilege ... if you're comparing briquette prices to logs, the log prices should at least be competitive!

HTH
Z

mmmmikey

Interesting....


The last load of kiln dried mixed hardwood I bought was in September 2018 at £255 for a 2.7cubic meter load loose logs tipped on the drive. Obviously I paid more for having it kiln dried (15-20% moisture) rathered than seasoned (30-40% moisture). If I'd bought the same logs from the same supplier seasoned it would have cost £210 for 2.7cubic meters, equivalent to £230ish for 3 cubic meters, so a fair bit more than you're paying. This is a fairly competitive price locally - I shopped around and could have saved £20 or so off that but went with my usual supplier because I knew I'd be getting good logs (and I like the guy!). Still quite a big difference. The same logs in September 2017 would have been £180 for 2.7 cubic meters (prices have gone up a lot locally) - is your price still current?


I did try a load of seasoned logs myself but found that I had to have the fire really hot to keep it going, which resulted in using far more and having to open the window to let out the spare heat. I do check the logs from time to time with a moisture meter so I'm confident that they were well seasoned.


I am very confident of achieving the (significant!) savings I outlined because I know how many logs I used last season and how many I've used this season, and even after a week can easily predict how many briquettes I'll use. Estimating is as easy as counting the number of briquettes I use to run the stove for an evening for a given time and over a week or so it's been very consistent.



Having said that, if your logs are much cheaper to start with and you're getting good results with seasoned as opposed to kiln dried logs clearly you're not going to save as much, if at all.


Thanks Mike

mmmmikey

Sorry Z - another question I forgot to ask - you mention chopping logs in your previous post, is this something you're doing yourself or do they come in sizes ready to use? Mine are chopped down to usable sizes and although I need to split down 1 big log into 2 once a week that's all. Maybe that accounts for some of the difference?

silverwhistle

mmmmikey wrote: »

Obviously I paid more for having it kiln dried (15-20% moisture) rathered than seasoned (30-40% moisture).

Hmm, 30-40% is not my definition of seasoned! Depending on the wood that sounds like they've been left a little while (a variable period..) before selling. The whole essence of a seasoned log is that it's ready to burn otherwise the term is meaningless.


To comment also on your point about splitting: the earlier you do this the better for additional drying, but I understood most suppliers deliver cut _and_ split. I only have big "cheeses" stacked around my garden for space saving reasons. Come the spring I'll split them for next winter (or winter after that) as they've already been stacked under cover for more than a year.

jaybeetoo

mmmmikey wrote: »

The only downside I am finding is that although there is less ash with the briquettes, the ash that is produced is fine and powdery and makes the room a bit more dusty.

I don’t understand how your room is more dusty. Air should be taken from the room, into the stove and then up the chimney.

Have you got a good seal on the stove doors?

Perhaps your stove is a different design??

Have you got a carbon monoxide alarm in the room?

I burn briquettes and don’t get any dust in the room.

mmmmikey

Yes - describing logs as seasoned is about as useful as selling them by the load - both fairly meaningless unless backed up by numbers. Do you measure the moisture content of your seasoned logs and if so what is it?



Having looked into this further, Z has a good point - a fair chunk of my saving probably comes from the fact that I've been paying a bit too much for logs. I'm still confident of saving, even if I buy the cheapest logs I can find, but probably nearer to 30% than 40%. I'll know better tomorrow after phoning round.



One thing I do know with absolute certainty - my lounge is at a much more comfortable temperature burning the briquettes. I have a temperature data-logger that confirms this (although it's obvious anyway from just sitting here).

mmmmikey

Hi jaybeetoo



"I don’t understand how your room is more dusty."


Sorry, to clarify.....


1. When I open the door (even very slowly) to put the next briquette on I sometimes get a small puff of powdery ash


2. Most of the dust comes when I'm emptying the ashes out because it's just so much finer and more powdery than "regular" ash


No ash at all while the door is closed and the fire is burning, and yes to the question about the CO alarm.