Heating Cost Comparisons

[Alan de Enfield]

In a recent thread, a comment was made regarding the high cost of heating when using LPG, however when looking at the heat output (Kwh) for each type of 'material', then taking into account the conversion efficiency the results may not be as clear cut as you may imagine.

1Kg LPG = 14.1Kwh and conversion is 90% efficient

1kg Coal = 6.9Kwh and conversion is 75% efficient

1kg of Smokeless fuel = 6.7Kwh and conversion is 75% efficient

1kg of Seasoned wood = 4.2Kwh and conversion is 85% efficient

1kg of diesel = 12Kwh and conversion is 90% efficient.

Compare 'smokeless fuel' with LPG with Diesel

LPG

Cost of a 13kg cylinder = approx. £25, or, £1.92/kg.

14.1Kwh @ 90% efficiency = 12.69Kwh

12.69Kw costs £1.92, or, approximately £0.15 per Kwh

 

Smokeless Fuel

Cost of 20kg bag = approx. £11, or, £0.55/kg

6.7Kwh @ 75% efficiency = 5Kwh

5Kwh costs £0.55, or, approximately £0.11 per Kwh

 

Diesel

Cost per Kg (1.17 litres at £0.80/litre) = £0.94/kg

12Kwh @ 90% efficiency = 10.8Kwh

10.8Kwh = £0.94, or, approximately £0.09 per Kwh

 

[mrsmelly]

I think the problem with such as gas is that for instance if used in an alde c/h system is that it needs to run all night or the heat from rads disappears very very quickly whereas solid fuel stoves can tick over for hours for very little fuel and maintain a background heat when living aboard. To maintain my boat at 24 plus all day would methinks be expensive with gas and impossible or expensive with diesel wheras for max of a fiver a day I can be very warm and still ok overnight.

[nicknorman]

I think some of your figures are on the edge of reasonableness and if you move them more into the middle, the picture is a little different. So which LPG heaters are 90% efficient? Where on the cut do you get a 13kg cylinder for £25?

Similarly, diesel is around 65p a litre round here at 0% propulsion. But what diesel heaters are 90% efficient?

And yes buying coal in 20kg bags is expensive, coal is much cheaper when bought in bulk but agreed that is only any good if you have somewhere to store it!

In our marina, the unit price for electricity is 13p making electric heating (100% efficient) a good bet.

Edited December 27, 2017 by nicknorman

[bizzard]

13kg Calor have suddenly jumped up to £30.50p !!! here.

[Alan de Enfield]

19 minutes ago, nicknorman said:

I think some of your figures are on the edge of reasonableness and if you move them more into the middle, the picture is a little different. So which LPG heaters are 90% efficient?

All efficiency figures from a 'energy comparison' web site by 'Nottingham Energy'.

Where on the cut do you get a 13kg cylinder for £25?

Our BWML Marina

Similarly, diesel is around 65p a litre round here at 0% propulsion.

Don't forget we are comparing KGs and not litres. Our BWML marina is 80p/litre which equates to 94p/kg

But what diesel heaters are 90% efficient?

And yes buying coal in 20kg bags is expensive, coal is much cheaper when bought in bulk but agreed that is only any good if you have somewhere to store it!

In our marina, the unit price for electricity is 13p making electric heating (100% efficient) a good bet.

Agreed - ours is 15p 'all in' (no service charges) but for liveaboards on the cut with no hook-up marina electricity prices are pretty irrelevant

 

Edited December 27, 2017 by Alan de Enfield

[nicknorman]

7 minutes ago, Alan de Enfield said:

 

The latest condensing gas boilers are ~90% efficient, but many older types such as the Alde slimline ones popular on older boats are more like 70% .

[mrsmelly]

The beginning of the story is " Solid fuel rules " here endeth the lesson.

[reg]

Junked my ALDE due to the cost of running it and also the fact that you have to constantly find and change the cylinder, not practical  when CCing. 

[peterboat]

I paid £6.75 for 25 kilos of anthracite about 46 p per litre for my last diesel and and 53.7 per litre for the last gas we bought clearly it pays to shop around

[rgreg]

1 hour ago, reg said:

Junked my ALDE due to the cost of running it and also the fact that you have to constantly find and change the cylinder, not practical  when CCing. 

I find that a solid fuel stove with Alde as occasional secondary heating, plus hot water, works fine. The cost of using the Alde as the primary heating source would be prohibitive.

[Flyboy]

3 hours ago, nicknorman said:

 Where on the cut do you get a 13kg cylinder for £25?

 

Fradley junction Kingfisher Cafe/Caravan Park   £22 recently. Also for similar price at Capital Gas  Etruria between the top lock and the Black Prince hire base.

[dccruiser]

In my experience , (i have both an eberspacher and a solid fuel stove) If i use the eberspacher as i did last winter on a 24/7 basis i used around 160 quid a month in diesel ... using my coal stove 24/7 costs me half of that and the boat is like a sauna even the far end is warm enough and without an eco fan in sight!  

Rick

[beerbeerbeerbeerbeer]

4 hours ago, bizzard said:

13kg Calor have suddenly jumped up to £30.50p !!! here.

And I'm getting 25kg coal under a tenner, which wobbles the original figures too. 

And dont forget the 'free' wood that feeds the stove. 

[dccruiser]

4 minutes ago, Goliath said:

And I'm getting 25kg coal under a tenner, which wobbles the original figures too. 

And dont forget the 'free' wood that feeds the stove. 

What are summers for if not to season wood ready for the winter ... and who doesnt carry a chainsaw "just in case"?  

Rick

[Detling]

Don't forget that many diesel and gas heaters require circulating pumps and boiler fans use 12 volt power (my webasto  uses 2.5 amps) which has to be replaced somehow. This is very unlikely from solar at this time of year, so engine or generator at loads per kilowatt. 

[mrsmelly]

5 minutes ago, Detling said:

Don't forget that many diesel and gas heaters require circulating pumps and boiler fans use 12 volt power (my webasto  uses 2.5 amps) which has to be replaced somehow. This is very unlikely from solar at this time of year, so engine or generator at loads per kilowatt. 

Yep...post seven says it all.

[beerbeerbeerbeerbeer]

14 minutes ago, dccruiser said:

What are summers for if not to season wood ready for the winter ... and who doesnt carry a chainsaw "just in case"?  

Rick

And a chippy gave me several door frames/casings the orher day! Free wood comes in all ways. Lovely. 

 

[dccruiser]

1 minute ago, Goliath said:

And a chippy gave me several door frames/casings the orher day! Free wood comes in all ways. Lovely. 

 

The last wood i got i was paid 20 quid to take to the tip! ... someone wanted a garage clearing ... 3 bags of rubbish the rest was wood

Rick

[smileypete]

Some of those numbers look a bit iffy, anthracity and decent smokeless is close to 9kWh/kg and butane should be a bit lower for 'LHV - lower heating value' say 1.25kWh/kg

Gernerally IIRC grid leccy comes out to 2 or 3x the cost of coal, and calor price their bottled gas as high as poss without costing much more than grid leccy, so as not to lose too much sales. Dunno about red diesel/kero though, much depends on the oil market.

Smokeless should be very efficient in a stove on tickover, the flue near the chimney collar may only be lukewarm.

Edited December 27, 2017 by smileypete

[Alan de Enfield]

30 minutes ago, smileypete said:

butane should be a bit lower for 'LHV - lower heating value' say 1.25kWh/kg

Is butane generally used ? I thought Propane was the norm.

I am assuming that your quoted LHV is a 'typo' and should read 12.58Kwh/kg, (Propane LHV is 12.9Kwh/Kg)

Edited December 27, 2017 by Alan de Enfield

[cuthound]

5 hours ago, mrsmelly said:

I think the problem with such as gas is that for instance if used in an alde c/h system is that it needs to run all night or the heat from rads disappears very very quickly whereas solid fuel stoves can tick over for hours for very little fuel and maintain a background heat when living aboard. To maintain my boat at 24 plus all day would methinks be expensive with gas and impossible or expensive with diesel wheras for max of a fiver a day I can be very warm and still ok overnight.

My drip feed diesel stove uses less than 0.25 litres per hour on its lowest setting, whilst maintaining the boat at around 23-29°C in at or below freezing temperatures. With diesel currently at around 70 ppl it costs just £4.20 per day,  is easily controllable an only needs cleaning out once every 3 weeks of 24/7 use. 

[dccruiser]

3 minutes ago, cuthound said:

My drip feed diesel stove uses less than 0.25 litres per hour on its lowest setting, whilst maintaining the boat at around 23-29°C in at or below freezing temperatures. With diesel currently at around 70 ppl it costs just £4.20 per day,  is easily controllable an only needs cleaning out once every 3 weeks of 24/7 use. 

My neighbour has one and swears by it ... he has used half the fuel running his I would have used in the same period running my ebby.

Rick

[mrsmelly]

6 minutes ago, cuthound said:

My drip feed diesel stove uses less than 0.25 litres per hour on its lowest setting, whilst maintaining the boat at around 23-29°C in at or below freezing temperatures. With diesel currently at around 70 ppl it costs just £4.20 per day,  is easily controllable an only needs cleaning out once every 3 weeks of 24/7 use. 

Have you got a whole boat? or is it one of those tiny sixty footers or somett? they should be able to be heated for about ten bob  If it is proper as in 68 feet or more  then I submit.

[cuthound]

1 minute ago, mrsmelly said:

Have you got a whole boat? or is it one of those tiny sixty footers or somett? they should be able to be heated for about ten bob  If it is proper as in 68 feet or more  then I submit.

60 foot, but then my cabin is as long as yours coz it's a proper trad, not a semi-trad with a long rear deck and shorter cabin.  

[cuthound]

5 minutes ago, dccruiser said:

My neighbour has one and swears by it ... he has used half the fuel running his I would have used in the same period running my ebby.

Rick

Yes, I have a Webasto as well as the drip feed stove.

Whilst good for warming the boat quickly on chilly Autumn and Spring mornings and evenings, it costs more to run than the drip feed stove, whilst not getting the boat as warm.

I was sceptical of it at first and planned to swap it for a multi-fuel stove, but once I had  fettled it and understood how to get the best from it, I wouldn't go back to a multi-fuel stove unless the price of diesel rises dramatically over coal.