Sawdust heat logs: the perfect wood burning stove fuel

Today I re-ordered a full pallet of sawdust briquettes from UK Heatlogs. In January, we took advantage of an offer to buy a 1000kg pallet of their ‘B grade’ bagged sawdust heat logs and after our previous year of bad wood, haven’t looked back since. For the benefit of new readers, we have three fires in our house, and we need them, since they are our only source of heat and hot water (and we actually don’t want to change that). One of our stoves is a range cooker, so much of our cooking is fired by solid fuel.

UK Heatlogs

The advantages of UK Heatlogs:

  • They burn hot
  • The leave very little ash. Scarily little!
  • The are clean. A bit of sawdust on the floor sweeps up easily and doesn’t mark, unlike coal
  • They are consistently dry
  • They can be broken up into smaller discs to start a fire more easily
  • They are easy to light – they’re so dry
  • If you load up your stove, get it blazing, then turn down the airflows, they can burn all night and still have some embers glowing by morning
  • They are environmentally sound – turning waste from the timber trade into fuel
  • UK Heatlogs are now HETAS approved
  • No more nasty coal dust

ukheatlogs-burningI could go on: neat bags stacked up to the roof in our wood shed. Clean bags – a few of which we can stack inside so that we don’t have to brave the Cornish rain driving in off the sea (and it rains a great deal here). We can now get a fire going and the house warm really quickly, and also be sure that when we wake up, the stove will still be hot and be quick to get blazing again if it’s cold outside.

I wish we could say the same of the wood that we have tried from five different suppliers over the past year.

When ordering a new pallet of their ‘A grade’ bagged heat logs this morning, I spoke with Christian, who told me that they are trialling the sale of their heat logs at Aldi. Let’s hope more people discover them, because it’s a big relief when you rely on solid fuel to find something that’s efficient, and you get on with.

Without wishing to sound like an advert, and I have no relationship with them other than as a customer, but if you are hunting for a consistent fuel for your wood burning stove, do have a look at the UK Heatlogs website and as we did, order a trial box. After your first pallet, you won’t look back.


The trials of finding a supplier of dry seasoned firewood, ready to burn, in west Cornwall


[Update April 2017] We still buy wood from Iglu, and still highly recommend them, but we have now sold our Esse Ironheart and have had central heating installed. Read why.

[Update February 2015] We are now buying our wood from Iglu, a Cornish company based near Looe.

We live in a terraced house in Penzance. Our three fires are our only form of heating, which is how we like it. We have a highly efficient Town & Country Farndale wood burning stove in our lounge, a small open fire in the second reception room, and an Esse Ironheart in our dining room which adjoins the kitchen. The Ironheart also provides our hot water via a thermal store and gravity system, and we cook on and in it. We use just under a cubic metre of wood each month.

We have now had firewood from five six different suppliers. Five of them have supplied second-rate wood, with moisture readings from 30% to off-the-scale. The one who supplied the best wood ironically wasn’t keen to deliver to us again as they could not tip the load of wood onto a driveway. Another local supplier refused to deliver at all after I described where we lived, as it seems tipping the wood is the only method many are prepared to do.

Wood, it seems, is a fuel often just burned as an occasional luxury by people with large houses, their own driveway, plenty of money, and no knowledge of what dry, seasoned wood, is like.

Is it local wood?

The last load of wood we bought, from another of the larger firms west of Truro, turns out to have been imported from Latvia, according to the driver. I was aghast as all this wood was piled up in our yard, to learn that it had come from such a long way away, making no environmental sense whatsoever.

Stacking Fee

Cornish Firewood delivers wood in netted bags as standard, and the driver will generally help to get your wood as near as possible to your store. Other suppliers such as South West Forestry will charge a £10 “stacking fee” to take a loose load through a property. I can see that this is fair enough, as if there’s a lot of wood this can take a while, and time is money, after all.

Wood as a variable product

Wood is, after all, a natural and variable source of fuel. However, people have seasoned firewood for millennia. Is it a lost art? Perhaps. With the exception of the first load of logs we got from B&B Logs, the moisture content has been all over the place. None of the others have managed to supply seasoned wood with a moisture content under 30%. The Latvian wood has been closest to this mark, being 30-35% on average. Twice we have been given unseasoned or only partially seasoned wood when paying for seasoned. The “largest” supplier of firewood in these parts who delivers in netted bags eventually, after much argument, replaced the unseasoned wood with what was claimed to be kiln-dried, yet the larger pieces still had a moisture content of above 30%. But there’s only so much complaining one can do…

Our chimney sweep told us that on visiting one of the suppliers we have tried, they were stacking their wood to ‘season’ in such a way that air could not pass through and had to encourage them to re-stack it. Simply leaving wood in piles for set six months does not constitute seasoning. This news did not fill me with confidence for our prospects of finding someone who can supply regular loads of dry, seasoned, ready to burn firewood.

It turns out that over the border in Devon we’re not alone with our frustrations.

What’s the alternative?

Our last delivery of wood came from South West Forestry, and along with the (well-travelled) wood, we ordered 10 packs of their local sawdust briquettes. They are fantastic. Bone dry, quick to light, loads of heat, and consistent. They were £3.95 per pack of 12 and we used on average 4 per day to mix in with logs to get it all going. But what about using them as the primary form of fuel, and just mix a few logs in? The key is to find sawdust logs that are good, and affordable, and buy them in bulk.

Our next experiment is with a palette of UK Heatlogs, which should arrive in the next few days. 81 12kg bags of sawdust logs for £175; fuel which has a moisture content of about 6%. We bought a tester pack last year and were astounded by how hot they burned. Now we have more experience ‘driving’ our stoves, we should get a lot out of them.

[Update May 2014] We burned heat logs exclusively for over a year. However, we’ve converted our Esse Ironheart to be wood-burning only since we don’t use coal, allowing us to fit more fuel in and get a better overnight burn. However, this wasn’t great for the heat logs, which tended to collapse into dense piles of hot sawdust and not get as hot as we’d like. Heat logs are better on a multi fuel grate in our experience.

So we have returned to using wood. One other supplier of ‘seasoned’ wood was tried, and a mixed load was ‘mixed’ in moisture too, from 25% to 40%. We will have a big stack of this wood in our woodshed for a long time to come while it dries out. I’m slowly splitting the bigger logs to help them dry out more quickly.

A pallet of kiln-dried Ash logs from Kuggar Stoves was the best wood we’ve ever had, and so, if we can get a slightly better price than £155/m3 we’ll burn that from now on, and perhaps mix in some of our last loose load of ‘seasoned’ as we go.


Farndale with smokeless coal (Thermaheat by Semmens)

image The winter is setting in. Temperatures in west Cornwall are going down although not as dramatically as elsewhere. But now is the time to test how much heat we can get out of our solid fuel heating and hot water system. Having recently had a second bad experience with a major local wood supplier we decided to embrace smokeless coal more fully.

Our previous smokeless coal order was for 125kg of Ecoal by Homefire. It is a hexagonal large briquette which needs a good bed of embers to get going but then keeps going for many hours and we successfully used it to keep our Esse Ironheart ‘in’ all night. This meant a nice warm bathroom in the morning (towel rail heat leak radiator), plenty of hot water and a ground floor that isn’t ‘bracing’.

We turned to our most local coal merchant Semmens for our next order and decided to order a variety of the cheaper and more expensive smokeless coals, in addition to naturally smokeless anthracite. Reviews are difficult to decipher as are descriptions so we wanted to find out for ourselves whether paying more necessarily gets you a) higher heat output b) long lasting heat.

Our front of house heating is provided by a Town and Country Farndale, a super efficient multi-fuel burner but whose capability on coal we hadn’t fully discovered. Yesterday I built up a fire just with a firelighter and bone-dry kindling. Then slowly added layers of Thermaheat, a much smaller ovoid briquette than the larger Ecoal or related Homefire briquettes. Semmens’ Thermaheat is about a quarter less of the price of Ecoal and Homefire and was at the base end of the range we are currently trialling.

It worked a treat in the Farndale. In total I loaded a medium sized bucket load into the firebox and it lasted for at least seven hours, kicking out a high amount of heat. We knew this because we ran our Kontax Sterling Engine heat fan on top and it was going like the clappers, just like it has on high-output logs or heat logs. We did not add any more before bed-time so it was out by morning, but if we had, I am certain we would have come down to a bed of red hot embers.

I think their smaller size and shape mean they are much easier to get alight without the need to create a wood ember bed, allowing air to flow all the way around the firebox and using the fine tuning of the Farndale to its best.