Log burner investment?

Olly_J

QrizB said:

A 1-tonne bag of logs contains about 1200kWh of heat, and a stove is rather less efficient than a boiler. I'm not saying you won't save money, but I think your estimate is on the high side.

Just a query on that calculation, kiln dried firewood <=20% moisture is usually listed as having a heating value of around 5Kwh per KG, so if it really is 1000KG of wood delivered it should be around 5000KWh worth of heat?

Qyburn

If the "1-tonne" is a standard builder's bag, they're somewhere in the range of 0.6 to 0.8 cu.m.  Filled loose that's going to be around 150 to 200kg of softwood, or maybe 200-220 for hardwood but that could be wildly different if it was say Beech vs Willow.

However it does depend on the bag, we took one cu.m of softwood and one of hardwood and the bags are much bigger than your normal builders bag.

Regarding savings, just speaking for ourselves I'm sure part of the benefit is due to only heating the living room rather than the whole house.

QrizB

Qyburn said:

If the "1-tonne" is a standard builder's bag, they're somewhere in the range of 0.6 to 0.8 cu.m.  Filled loose that's going to be around 150 to 200kg of softwood, or maybe 200-220 for hardwood but that could be wildly different if it was say Beech vs Willow.

Yes, this. And also:

Olly_J said:

QrizB said:

A 1-tonne bag of logs contains about 1200kWh of heat, and a stove is rather less efficient than a boiler. I'm not saying you won't save money, but I think your estimate is on the high side.

kiln dried firewood <=20% moisture is usually listed as having a heating value of around 5Kwh per KG,

Kiln dried could be 5kWh/kg, but air dried to 20% moisture is more like 4kWh/kg net per UK gov't figures at Forest Research.

Qyburn

QrizB said:

Kiln dried could be 5kWh/kg, but air dried to 20% moisture is more like 4kWh/kg net per UK gov't figures at Forest Research.

I've not seen many kiln dried suppliers promising less than 20% so in reality there's little difference. Our own air dried settles down to between 15 and 20% by the time we use it. Conversely poorly stored kiln dried will soon take up moisture and end up worse than decent air dried.

Cautiouslyoptimistic

Just on the logs point and just coming away from the science for a moment, I'm extremely confident that two one tonne builder's bags of wood (and it's about 50/50 hard/softwood) will last us for 4 weeks in the coldest days to come and that means we will keep warm for £110 per month. Admittedly, we have a very cheap wood supplier.

November is looking reasonably mild so far so it's entirely possible that we will be running out of space to put next months delivery. 

Funny really, by having a warm room in the house, everyone now tends to congregate in one place. The kids are not sat in their bedrooms on the laptops and phones, and we all enjoy a bit of conversation.    

ariarnia

Cautiouslyoptimistic said:

Just on the logs point and just coming away from the science for a moment, I'm extremely confident that two one tonne builder's bags of wood (and it's about 50/50 hard/softwood) will last us for 4 weeks in the coldest days to come and that means we will keep warm for £110 per month. Admittedly, we have a very cheap wood supplier.

November is looking reasonably mild so far so it's entirely possible that we will be running out of space to put next months delivery. 

Funny really, by having a warm room in the house, everyone now tends to congregate in one place. The kids are not sat in their bedrooms on the laptops and phones, and we all enjoy a bit of conversation.    

we do something similar and agree its good to have family time (though i dont know how its going to work once they are teenagers!). 

for us we're not using much wood at the moment and can make a builders bag equivalent (say about half a m3 when stacked) last a month. but as a warning last jan we were lighting the fire and keeping it lit from first thing in the morning not just in the evening (i think it was averaging about 3 degrees here) and could get through nearly a bag in a week. this year we have a couple of bags of coal in reserve just in case as its actually a bit of a pain to keep putting logs on every 45 mins or so (i work from home so gave in and kept a small oil filled radiator under my desk for the days i was forced to be sat at the laptop all day and no one else was going to be home until at least 4)

Ally_E.

Cautiouslyoptimistic said:

We had a Blithfield Clock 5 kwh wood burning log stove installed 3 years ago on 0% finance spread over 12 months.  It wasn't cheap as we also needed chimney repairs to make it work. It was only ever intended to be a focal point for the lounge replacing a 30-year-old clapped out gas fireplace. However, fast forward 3 years and we are now in the midst of a fuel price crisis. Based upon a 4-bed detached house, our predicted annual fuel bill based on the October government capped rates was just under £4,700 over the next 12 months.  This included about 27,000 kwh of gas of which about 24,000 kwh was used between October '21 and March '22. That's nearly £2,500 on this years "fixed rates" JUST for central heating over 6 months or £416 per month / £104 per week.

During October just gone and mostly as a trial we bought two 1 tonne builders' bags of chopped log delivered including free kindling wood. We used 338 kwh of gas as opposed to 2,048 kwh last October, so we saved about £100 on gas heating just in October.  If we can get through the next 5 months by just using the log burner during the days and evenings, then we will save thousands on the gas central heating.

Personally, if you already have a log burner installed then you would be mad not to use it IF you can find a reasonably priced wood supply.  Mentally I've written off my install costs from a few years ago and now everything saved on using gas is a plus. I'm a week into November and I've only used 105 kwh. It won't go above 400 kwh which will be a further saving of 3,400 kwh on last years use.  For us it's a no brainer.  The gas CH is not being turned on.    

 

The logburner gets the living room nice and toasty, but the rest of the house is not heated. Especially the bedroom which is above the living room. So going from living room at 18-19C at night to a bedroom that's 14-15C is quite a shock. That temp in the bedroom will continue to go down. So I'm not sure how to balance that. I ended up turning the heating on for a bit just to get the bedroom warmer before bed and that would heat the living room too which was wasteful. 

Longwalker

Ally_E. said:

Cautiouslyoptimistic said:

We had a Blithfield Clock 5 kwh wood burning log stove installed 3 years ago on 0% finance spread over 12 months.  It wasn't cheap as we also needed chimney repairs to make it work. It was only ever intended to be a focal point for the lounge replacing a 30-year-old clapped out gas fireplace. However, fast forward 3 years and we are now in the midst of a fuel price crisis. Based upon a 4-bed detached house, our predicted annual fuel bill based on the October government capped rates was just under £4,700 over the next 12 months.  This included about 27,000 kwh of gas of which about 24,000 kwh was used between October '21 and March '22. That's nearly £2,500 on this years "fixed rates" JUST for central heating over 6 months or £416 per month / £104 per week.

During October just gone and mostly as a trial we bought two 1 tonne builders' bags of chopped log delivered including free kindling wood. We used 338 kwh of gas as opposed to 2,048 kwh last October, so we saved about £100 on gas heating just in October.  If we can get through the next 5 months by just using the log burner during the days and evenings, then we will save thousands on the gas central heating.

Personally, if you already have a log burner installed then you would be mad not to use it IF you can find a reasonably priced wood supply.  Mentally I've written off my install costs from a few years ago and now everything saved on using gas is a plus. I'm a week into November and I've only used 105 kwh. It won't go above 400 kwh which will be a further saving of 3,400 kwh on last years use.  For us it's a no brainer.  The gas CH is not being turned on.    

 

The logburner gets the living room nice and toasty, but the rest of the house is not heated. Especially the bedroom which is above the living room. So going from living room at 18-19C at night to a bedroom that's 14-15C is quite a shock. That temp in the bedroom will continue to go down. So I'm not sure how to balance that. I ended up turning the heating on for a bit just to get the bedroom warmer before bed and that would heat the living room too which was wasteful. 

Why are you only getting up to 18/19 degrees?

A couple of logs and my living room which is 25 by 36 and has no door to the stair well, will heat to 26 - 28 within an hour or so if fed. Indeed we light at 4 or 5 pm and stop feeding around 8pm. Actually the fan is still turning very lazily at near on 12pm, and there wasnt a log put on after 7pm

My house is a bit weird, my living room is upstairs, and the bedrooms and bathroom open off from it, no hall way so all the rooms are toasty by opening the doors to disperse the heat

dunstonh

Ally_E. said:

Cautiouslyoptimistic said:

We had a Blithfield Clock 5 kwh wood burning log stove installed 3 years ago on 0% finance spread over 12 months.  It wasn't cheap as we also needed chimney repairs to make it work. It was only ever intended to be a focal point for the lounge replacing a 30-year-old clapped out gas fireplace. However, fast forward 3 years and we are now in the midst of a fuel price crisis. Based upon a 4-bed detached house, our predicted annual fuel bill based on the October government capped rates was just under £4,700 over the next 12 months.  This included about 27,000 kwh of gas of which about 24,000 kwh was used between October '21 and March '22. That's nearly £2,500 on this years "fixed rates" JUST for central heating over 6 months or £416 per month / £104 per week.

During October just gone and mostly as a trial we bought two 1 tonne builders' bags of chopped log delivered including free kindling wood. We used 338 kwh of gas as opposed to 2,048 kwh last October, so we saved about £100 on gas heating just in October.  If we can get through the next 5 months by just using the log burner during the days and evenings, then we will save thousands on the gas central heating.

Personally, if you already have a log burner installed then you would be mad not to use it IF you can find a reasonably priced wood supply.  Mentally I've written off my install costs from a few years ago and now everything saved on using gas is a plus. I'm a week into November and I've only used 105 kwh. It won't go above 400 kwh which will be a further saving of 3,400 kwh on last years use.  For us it's a no brainer.  The gas CH is not being turned on.    

 

The logburner gets the living room nice and toasty, but the rest of the house is not heated. Especially the bedroom which is above the living room. So going from living room at 18-19C at night to a bedroom that's 14-15C is quite a shock. That temp in the bedroom will continue to go down. So I'm not sure how to balance that. I ended up turning the heating on for a bit just to get the bedroom warmer before bed and that would heat the living room too which was wasteful. 

A couple of things on this.....

18-19c from a room with a burner in seems very low.  Certainly not toasty.   Do you have a fan on top of your burner?

And your bedroom falling to 14-15c at this time of the year suggests insulation problems. I live in an big old house with poor insultation and it is only falling to 18.5c when there is no heating for many hours.

And finally, why would turning the heating on for the bedroom heat the living room?  Your radiator TRVs would prevent the heating in the room with the burner from coming on in there.    Are your radiators missing TRVs or are perhaps you have them set too high?

I am on oil central heating and like very many rural properties, we have burners to reduce the amount of oil that is used.  We have 3 burners.  Two of them only heat the room they are in.  The third is in the hall and that has a number of rooms and one of the stairways coming off it and has good airflow that does transfer the heat around the house.    When that one is on, it prevents four radiators from coming on and slightly increases the heat in two of the bedrooms.

ariarnia

dunstonh said:

Ally_E. said:

Cautiouslyoptimistic said:

We had a Blithfield Clock 5 kwh wood burning log stove installed 3 years ago on 0% finance spread over 12 months.  It wasn't cheap as we also needed chimney repairs to make it work. It was only ever intended to be a focal point for the lounge replacing a 30-year-old clapped out gas fireplace. However, fast forward 3 years and we are now in the midst of a fuel price crisis. Based upon a 4-bed detached house, our predicted annual fuel bill based on the October government capped rates was just under £4,700 over the next 12 months.  This included about 27,000 kwh of gas of which about 24,000 kwh was used between October '21 and March '22. That's nearly £2,500 on this years "fixed rates" JUST for central heating over 6 months or £416 per month / £104 per week.

During October just gone and mostly as a trial we bought two 1 tonne builders' bags of chopped log delivered including free kindling wood. We used 338 kwh of gas as opposed to 2,048 kwh last October, so we saved about £100 on gas heating just in October.  If we can get through the next 5 months by just using the log burner during the days and evenings, then we will save thousands on the gas central heating.

Personally, if you already have a log burner installed then you would be mad not to use it IF you can find a reasonably priced wood supply.  Mentally I've written off my install costs from a few years ago and now everything saved on using gas is a plus. I'm a week into November and I've only used 105 kwh. It won't go above 400 kwh which will be a further saving of 3,400 kwh on last years use.  For us it's a no brainer.  The gas CH is not being turned on.    

 

The logburner gets the living room nice and toasty, but the rest of the house is not heated. Especially the bedroom which is above the living room. So going from living room at 18-19C at night to a bedroom that's 14-15C is quite a shock. That temp in the bedroom will continue to go down. So I'm not sure how to balance that. I ended up turning the heating on for a bit just to get the bedroom warmer before bed and that would heat the living room too which was wasteful. 

And your bedroom falling to 14-15c at this time of the year suggests insulation problems. I live in an big old house with poor insultation and it is only falling to 18.5c when there is no heating for many hours.

i dont know where in the country you are but here the average temp hasn't gone above 17 all month so unless we put the heating higher than 17 no chance the bedrooms are going to be at 18 at bedtime. the stove in the lounge leaks some heat through the floor but not that much. mostly its just the hall and kitchen that get any escaped heat. 

our lounge is defnately hotter than 19 with the stove lit but i get the impression ally has the same arrangement as we do given they say theres no heating in the rest of the house. (and agree they need to turn off the radiators in the lounge or get valves fitted if they dont already have them)