Very nerdy question but I’m bored…

I know it’s impossible to be accurate here as wood / moisture / stoves / room size / temperature all vary hugely but I thought I’d carry out a quick straw poll.

At the moment I’m burning a 5kw stove with 100% spruce. It’s all been cut to 200mm lengths (it fits in my stove nicely!) and it all has a moisture content of below 20%. Each 200mm ‘log’ was then split into 4-6 single pieces / lumps depending on the girth of the log. I probably averaged 5 over the whole job.

I collected / cut / chopped 60 x 3m lengths which roughly works out as 9m2 of wood when stacked.

[url=https://flic.kr/p/q8N1eS]IMG_1466[/url] by Rosscopeco, on Flickr

So, some questions and here’s my answers…

Stove size: 5KW
Hard / mixed / soft wood: Soft
Average % content: <20%
Hourly / daily burn rate: 2 lumps per hour
Yearly usage: 9m2 (fingers crossed)

I reckon I’ve burnt about 3/4 Sycamore tree over the last 2-3 months. I cut down 1.5, so will run out sometime towards the end of Jan….

Mines a bit of a special case as I run my Central Heating and Domestic Hot Water off logs via a furnace. I also have two stoves as well although I rarely have them both going at once.

Depending on the weather (so for this exercise lets say it’s 0-7 degrees in the day and -5 to 3 degrees at night) I expect to use 2-3 Ikea bags a day in the furnace AND in one of the stoves. And this is in a 3,000 sq ft converted barn.

Mine is all poplar harvested from my own coppice, and seasoned under cover until it’s <20%. Its not a dense wood so energy per bag isnt high, but it burns fast and hard, ideal for the furnace where all that energy is collected as fast as it is produced.

Each bag weighs approximately 20Kg, so assuming I burn on average 50Kg in a cold winter’s day, then that represents roughly 200kWH of energy (going on net 4kWh /Kg), 100-150kWh on a milder day. DHW normally accounts for around 25-40kWh a day I think.

This is from summer before last. It will have done 2+ a bit seasons by the time it’s all gone. It’s probably around 30-40m3, but since it’s all soft poplar that’s not much help for comparison.

This is data I recorded a few years ago when the boiler was running only on pellets. The right hand scale is number of bags (blue dashed line smoothed consumption). A bag is 10Kg so in Pellet terms it was averaging around 40Kg a day in mid-winter. Pellets are around 5kWh/Kg, so again around 200kWh on a cold day, 2-3 bags (100-150kWh) on a milder one.

Last week I started harvesting for next winter at the coppice. I will bring back around 10 tons of wet wood over the next few months.

Nerdy enough for you? 🙂

How big is the Coppice, how old are the trees when harvested?

The coppice is 3.5 acres in size and is a regenerating growth from a clear-felled poplar plantation around 9years ago. I harvest around 1/8 of an acre a year and am planning on maintaining a 7-8 yr rotation.

This is it before I started,

This is it after the 2012 harvest

2.5m2/year. Or a shopping bag full per day (7.5kg) at the coldest time of year. The bag is lasting two days as it’s quite mild at present.

Stoner…you have won the nerdy crown! I salute you!

Ton a month ish

I get wood frequently.

Most stove users could reduce their wood consumption by between 25 and 50%, just by better control of their stove. I have three, one 13kw and two around 7kw, never more than two going at one time, mostly on all weekend and 5-6 hrs on an evening. Usually get through 3-4 cubes.

Not our main source of heating so about two tons a year of seasoned wood and let’s say 180 kilos a year of Pureheat smokeless, burned in one 6kw Dovre 250 stove and two very occasionally.

Stoner how’d you find the time? Do you work full time also? Thought you burnt pellets as well?

6-7m3 a year I estimate but it’s a mix of wood/coal/electric boiler.
Heating 3 bed house and hot water from a max output 15kW stove.

Stoner how’d you find the time?

I slot it in between school drop off and pick up.

Do you work full time also?

No. Im semi-retired/Semi-househusband/semi idle. I work a day or so a week. Then I have chores, the rest of the time I do projects that interest me or cut down trees and chop wood.

Thought you burnt pellets as well?

I turn the boiler over to pellets either when it’s very cold and the house needs a boost in the night while I zzzzzz or if Im on one of my trips to London so Mrs Stoner doesnt have to faff about with the furnace. The pellets are “Automatic”, on call. The furnace you have to think about, plan and then light. I burn <1ton of pellets a year. My neighbour (only has pellets) burns over 7 tons I reckon. The equivalent of 3,500 Litres of oil.

stoner,

what boiler is that – can it run on pellets or logs?

https://sites.google.com/site/woodviking2010/biotriplex-dual-fuel-boiler

Woodviking biotriplex

I love mine, but I can’t recommend it as it has never been MCS certified by the manufacturer. I installed mine long before domestic rhi so didn’t care. But new installations would be mad not to be.

drat, the whole rhi scheme seems a bit of a nightmare to find the right boiler,

I think there were issues getting government specs agreed for log burners. When they finally were it didn’t necessarily mean combined boilers would meet the requirements too. I’ve not been following it for ages so there must be some out there now.

Do the maths though. My boiler wasn’t very expensive. So I don’t need rhi to be happy with the financial, many super whizzy approves boilers are very expensive and need the rhi to make them work.

I have a guesstimate of 15 m^3 per year depending how cold it gets.
That’s 95% of heating and all hw in winter – solar thermal provides most of the hw from May-October
The remaining 5% is oil – when I’m away and mrsj can’t be arsed with lighting the stove.
Most of the wood I burn is oak, with some birch and a bit of larch.

Apparently you lot burning wood with stove is causing smog in some area according to the “people newspaper”.

😯

Rather a long way from home for you isn’t it?

25mins in the land rover.
When I head over its for at least 4 hrs work.

I understand that HERZ are releasing a 10/20/40kW log n pellet combo early in the new year.
Should be MCS and rhi certified by release.

Disclosure : I may have a HERZ logo on my work fleece.

This is about a weeks worth of 5 to 11 heating.What’s shown is cut up on site, then split at home. Stored on-site in log stores, so ready to burn.

Stove size: 7.5KW
Hard / mixed / soft wood: No idea
Average % content: <20%
Hourly / daily burn rate: Put on when fire needs it
Yearly usage: No idea

We don’t have CH (and why anyone would run a wood stove when they’ve CH is beyond me), just the stove and an AGA in an old Mill. House is warm.

Once cold enough (and living in Scotland this can easily be on a summers’ evening if required), the stove is put on when my son come home from school, and then run until we go to bed.

Usage really depends on the weather. This year (2014) I reckon only about 2.5 cubic meters whereas in 2012 I reckon we did 4 cubic meters due to the long winter.

We don’t have CH (and why anyone would run a wood stove when they’ve CH is beyond me), just the stove and an AGA in an old Mill. House is warm.

We have CH, but pretty much exclusively use the wood stove – you get a warm living room (which is all you really need in the evening) rather than a warmish house when you only occupy one room at a time. More than halved our gas bill….

(and why anyone would run a wood stove when they’ve CH is beyond me)

Cost: Free wood vs paid for oil.

Well, we had a wood stove running the CH.

From memory, last winter the range (18kw?) was eating ~25kg hardwood logs of a day at the weekend, running full bore for a few hours a day, spread out over the day. The house is 130m2. If we ran the 7kw lounge burner instead (generally weekdays) we might go through half that.

All bought in split and ready to go.

I’ve not yet turned my heating on!

I’m married. Our heating should be on in august. Apparently.

last year I spent £1,500,000 on timber. I reckon I burnt 25% of that for heating.
That’s quite a frightening amount….!

wtf tinybits?????

tinybits – Member
last year I spent £1,500,000 on timber. I reckon I burnt 25% of that for heating.
That’s quite a frightening amount….!

hardwood joinery/carpentry and you burned the off cuts?

or

big biomass installation at some grand NT property?

We have CH, but pretty much exclusively use the wood stove – you get a warm living room (which is all you really need in the evening) rather than a warmish house when you only occupy one room at a time. More than halved our gas bill….

This.

hardwood joinery/carpentry and you burned the off cuts?

This – damn expensive, but you can only optimise so much and the balance we would actually have to pay to dispose of so we’ve installed a biomass furnace and heat the place with it.

Oh, and almost everyone has a wood burning stove at home as well!

Can you not just sell the offcuts?

I buy bags of HW & SW offcuts from the local timber merchant, makes good kindling.

I’ve never kept track of how much we use.
I’ve got a huge pile of round hardwood and softwood, plus old building timber stored at my house that I have scavenged from anywhere I can, that I am gradually working my way through and restocking at the same time. I haven’t actually bought firewood for years.
I take a Land Rover load over to Mrs MTG’s every now and then as required.
It would be interesting to know how much we do use. The biggest problem though, would be asking her to count how many boxes she brings in the house without it sounding like I’m telling her not to burn so much of my wood. 😕

I could, but then I’d have to pay for heating, so I sell it in the summer only. The rest of the time it’s actually cheaper than the oil I’d have to use to replace it. Certainly selling it wouldn’t offset the cost.

We run a 5kw stove to heat downstairs and use approx 1 ton of mostly oak a month. My parents place goes through between 1 and 1.5 tons per week! New biomass boiler should be up and running by the end of the year so should make heating the old place loads easier.

We have two 10kw stoves in the house, an 8kw stove in my studio and a third 10kw stove in the gallery. We burn a mix of hard and soft wood.

I’ve never really calculated how much we use, but it will be a few tons a year. It always surprises me when I see how many deliveries a year the guys at the lodge have delivered each year, they too get through a lot and their place is a lot smaller than ours.

I really enjoy the process of ‘harvesting’ wood then processing it into logs and stacking it. I couldn’t live without it.