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.