Thursday, 12 December 2024

Supermarket Logs

We have three supermarkets next to each other who sell logs within easy distance.  namely ALDI, B&M, and Tesco.  I decided to compare their offering for firewood and do a practical test.

Lidl

Lidl advertise log bags of 8Kg for £5 in their leaflet. This is a good price. BUT they never have them actually for sale in our store.
 


Aldi

Aldi sell "Wood logs" but don't say if they are hard or soft wood.  I bought 4 bags at £5 each and the weights varied between 4.4 and 5.2Kg.  The average was 4.73 Kg which gave a price of £1.06 per Kg

These seem to burn similarly to the B&M birch logs below.


B&M


B&M sell Birch hardwood logs for £6 per bag.  Once again I bought 4 bags.  Weights ranged from 5.9 to 6.3Kg with a mean of 6.1Kg.
So average price is 98p per Kg.

Results
They start easily and burn well.  The air vent at the bottom needs to be completely closed to stop the logs burning too fast.  15 minutes after lighting there is obviously quite a bit of heat from the fire.

A softwood log (below) can be added but when a couple of fresh birch logs need to be added, after about 45-60 minutes, the softwood log will still not be burned out.



B&M also sell softwood logs for £5 per bag. Weights ranged from 5.2 to 6.9Kg (a big variation) and the mean was 6.15Kg giving a cost of 81p per Kg.

Results
They take a long time to get started.  The air vent at the bottom of the fire needs to be completely open.

30 minutes after lighting and not a lot of heat coming out.  

I finally had to add a couple of Aldi logs to get the fire to burn.

BUT, once the burner is hot from burning hardwood logs they burn quite well and relatively slowly.



Tesco also sell bags which look similar to B&Ms birch bags but they cost £8 per bag. 

Overall, B&M's birch logs seem the best option.  Aldi is cheaper per pack but the packs are smaller.  The softwood logs are OK to mix with the hardwood logs.

Heatlogs may be a little cheaper - an evaluation is needed.   

Our local Log supplier is Logans logs.  To get the price down to around £1 per Kg I'd need to buy 20 bags of 30 litre. Or maybe a lorry load
Now the wood is sold by the cubic metre. but as it says on Logan site:-
Please Note: 1 Cubic Metre Loose does not equate to 1 Cubic Metre Stacked.
So what does it equate to?  Bags will have around the same volume as stacked, but with a lorry load, who knows. 
We do not have a huge log store. I only just managed to store the 68Kg above.  So twenty 30 litre bags (or 200Kg) or a lorry load (whatever that weighs) is out of the question. So for us, it looks like supermarket kiln dried wood at around £5 or £6 per bag is the best buy.

This page indicates that there is not a big difference in heat output between the different types of wood.It is around 4.5KWh per Kg. At £1 per Kg that means energy via logs is around  22p per KWh.  As the burner is around 70% efficient that means around 32p per KWh into the room.

By comparison, our current electricity costs 21.93p per KWh. Now electric heaters are 100% efficient that would be 22p/KWh into the room. 

Our gas costs 5.63 per KWh which is a lot cheaper.  The boiler is very efficient at around 95% but that heat has to come through under floor piping where is will lose some heat.  Also it heats up the entire house.  
We have a thermostat in the living room but the other rooms are controlled by fairly crude thermostatic controls on the radiators. We tend to have the thermostat set to 22C but when the outside temperature is in single figures we cannot get the living room temperature above 20C with the gas central heating alone.  To get the living room temperature higher using the gas alone I'd need to increase the radiator water temperature.    

Update 6/1/2025
All of the logs I bought burned well, including the softwood after the burner was hot. There were certainly variations though - even between the same brand.  Sometimes they would burn happily with the bottom vent closed completely.  But sometime the vent needed to be open quite wide.

But now, all of the local supermarkets are out of logs, and we will be too - in around 3-4 days.  If I can't get any more at a sensible price (£1 per Kg or less) then we may have to revert to smokeless fuel.  

I have bought 10 fuel logs from B&M.  These cost £5 for 5 and each one weighs about 1.3Kg making them 77p per Kg.  


Update 9/1/2025
We are now out of logs.  We used the fire for 24 days since I bought 12 bags so a bag lasts around 2 days - slightly less as we had some old wood lieing about which I burned.
The fuel logs do not light easily and burn slowly.  Maybe OK to put into a hot fire as the logs are burning out down to keep some heat coming out.  They take a long time to burn out.

I have bought 3 10Kg bags of smokeless briquettes from Lidl at £6.49 per bag.  Logans Logs price is £18-£19.50 for 20KG bags. So 40% dearer.

The back firebricks in the burner were crumbling, so today I replaced them.  The old ones were fireclay but the new ones are Vermiculite They went in easily, but the oldbroken ones took some getting out.
 












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