woodburner running costs

[ab12]

For those members who have a log burner what are the running costof timber fuel  in the winter on average per month?

 

Am thinking of getting  5Kw or possible 7kw log burner and want to have a rough idea if I was too run it every day for about 4 hours  for the winter months, so at least 4 months,  say November to February how much would it cost to purchase the timbers say per month on this basis?

 

On average if you pack the burner with timbers how long does 1 burn cycle last?

 

thanks

[SteamyTea]

1 kg of seasoned hardwood has approximately 4.5 kWh of energy in it, when burnt in ideal conditions.

As wood burners are not very efficient devises, you probably need to halves that. So a 5 kW one will, if run properly, will take 2 kg an hour, but probably closer to 3 kg.

Burners can be adjusted to moderate thermal output, but that not only hurts efficiency, it also changes the combustion chemistry. Depending on the temperature of combustion, you also get varying amounts of particulates.

 

Then there is the land area needed to grown the timber. 

A metre² of land in the UK gets around 950 kWh of solar energy on it, trees convert, at best, 0.25% of that to timber. So sub 0.2 kWh/year.m². So to run a 5 kW burner for 1 hour is going to take, at very best, 15 m² of land.

Then you got the timber transport, storage, conditioning and waste disposal.

 

Do you really want a wood burner. Most houses got central heating in the 1950s and 60s.

[Bonner]

We get through one bulk bag a month, bought four bags last summer @ £90 each. I used to get most firewood free from work and neighbouring woodland but only getting a few scraps now.

[FarmerN]

5 Kw Wood burner running 27/7 from 1st Nov. to Mid April  used about 8 cuM of home produced wood. Stove would be shut down on low burn a lot of the time.

 

Now GSHP UFH etc but still light a stove for 1-2 hrs in winter , don’t need it but it’s nice and we have the wood.

[JohnMo]

5 hours ago, ab12 said:

For those members who have a log burner what are the running costof timber fuel  in the winter on average per month?

 

Am thinking of getting  5Kw or possible 7kw log burner and want to have a rough idea if I was too run it every day for about 4 hours  for the winter months, so at least 4 months,  say November to February how much would it cost to purchase the timbers say per month on this basis?

 

On average if you pack the burner with timbers how long does 1 burn cycle last?

 

thanks

It's a bit like saying how much gas will I use. The log usage (cost) really depends on the house heat loss and how hard you need to burn. When we run our 6kW log burner, we run it at very low loads, one log at a time, so about 2 logs has burn time of 3 to 4 hrs, you may have a higher heat loss so run 3 to 4 logs and lots of air, so get through loads more than me.

 

Cost also depends on how you source the logs. We have plenty of wood from cuts down down the build so zero cost, except my time.

 

Way to many variables to give you a cost that is meaningful.

[SteamyTea]

55 minutes ago, FarmerN said:

5 Kw Wood burner running 27/7 from 1st Nov. to Mid April  used about 8 cuM of home produced wood. Stove would be shut down on low burn a lot of the time

That is about 2.9 MWh of primary energy.