Heating Oil Consumption
Discussion
essayer said:
Still, assuming it’s linear,
Depends on the shape of your tank. The watchman gauge works using ultrasonics to measure distance from the sensor to the oil surface. If your tank tapers out towards the base then the top sections will drain more quickly than the lower ones. If be interested to know why modern boilers are more efficient "topping up" the heat in a hot water tank rather than heating the tank from cold.
There may well be some good engineery reason for this, but the pure physics of the heat exchange between the combustion gases and the primary circuit says "make the primary circuit flow as cold as possible so that the combustion gases are cooled as much as possible". That would mean that the boiler is naturally at its most efficient when the hot water tank is stone cold, and the efficiency inevitably rolls off as the temperature rises in the tank.
There may well be some good engineery reason for this, but the pure physics of the heat exchange between the combustion gases and the primary circuit says "make the primary circuit flow as cold as possible so that the combustion gases are cooled as much as possible". That would mean that the boiler is naturally at its most efficient when the hot water tank is stone cold, and the efficiency inevitably rolls off as the temperature rises in the tank.
Murph7355 said:
Do you know it's using that much for sure? Our level sender is nowhere near accurate enough to be able to tell.
I've been keeping measurements from our sender for a decade now, so know roughly how much it will drop at given times of year. Ours goes from '0' to 'F' and the increments are nowhere near even. It's accurate enough so I know when to call the oil people, and also to spot an issue in the house such as a stuck valve (though only over several months)...but I wouldn't want to try and gauge weekly consumption off the cuff from it.
What shape of oil tank do you have? A tank with vertical walls is likely to give more consistent increments, a tank with curved walls will drop quickly at the start, slower in the middle and quicker at the bottom for a consistent rate of consumption.I've been keeping measurements from our sender for a decade now, so know roughly how much it will drop at given times of year. Ours goes from '0' to 'F' and the increments are nowhere near even. It's accurate enough so I know when to call the oil people, and also to spot an issue in the house such as a stuck valve (though only over several months)...but I wouldn't want to try and gauge weekly consumption off the cuff from it.
Not read all the thread, just adding our experience.
2 of us.
Old house 3 bed semi detached from around 1900. No double glazing, oil heating and water but electric shower, open fire.
1000l would last 12 months.
New house, 4 bed barn conversion, it's about triple the size of the old place. Oil heating and water and 2 log burners. Does have double glazing but was built on the 1700s....old and damp lol
1000l has lasted about 10 maybe 12 weeks at a push.
2 of us.
Old house 3 bed semi detached from around 1900. No double glazing, oil heating and water but electric shower, open fire.
1000l would last 12 months.
New house, 4 bed barn conversion, it's about triple the size of the old place. Oil heating and water and 2 log burners. Does have double glazing but was built on the 1700s....old and damp lol
1000l has lasted about 10 maybe 12 weeks at a push.
Edited by Muppet007 on Saturday 15th January 10:19
We averaged 800l per month the first winter in our current house, got rid of the Aga and now use tado TRVs, only used 900l in the last 4 months.
What's the ballpark improvement in efficiency with a condensing boiler, 5-10%? I think usage would fluctuate more than that anyway, even if you don't notice it it you should be using less oil to do the same job...
What's the ballpark improvement in efficiency with a condensing boiler, 5-10%? I think usage would fluctuate more than that anyway, even if you don't notice it it you should be using less oil to do the same job...
Circa 2,300 litres per year. 17-year old, four bed, three reception detached house. Northern but Coastal.
Roughly 2-3 litres daily in the height of Summer, rising to between 4-7 litres in Spring & Autumn, and 8-11 litres daily in Winter - only use 10/11 litres in Jan & Feb.
That’s been with two of us working from home all the time since March 2020.
Use a timer, set to come on three times per day.
At worst, it’s on for about a set 4.5 hours in total in Winter, with an extra manually-set hour or so a day, if needed.
No electric showers, so the Oil heats the water too. In the Summer it’s mainly on to provide hot water rather than heating.
We do have two multi-fuel stoves but without a free source of wood (and being too fussy to burn ropey wood) they really aren’t used much and aren’t as cost-effective or convenient as Oil either.
I come from a colder family home, slowly training the wife to accept likewise.
Roughly 2-3 litres daily in the height of Summer, rising to between 4-7 litres in Spring & Autumn, and 8-11 litres daily in Winter - only use 10/11 litres in Jan & Feb.
That’s been with two of us working from home all the time since March 2020.
Use a timer, set to come on three times per day.
At worst, it’s on for about a set 4.5 hours in total in Winter, with an extra manually-set hour or so a day, if needed.
No electric showers, so the Oil heats the water too. In the Summer it’s mainly on to provide hot water rather than heating.
We do have two multi-fuel stoves but without a free source of wood (and being too fussy to burn ropey wood) they really aren’t used much and aren’t as cost-effective or convenient as Oil either.
I come from a colder family home, slowly training the wife to accept likewise.
ATG said:
If be interested to know why modern boilers are more efficient "topping up" the heat in a hot water tank rather than heating the tank from cold.
There may well be some good engineery reason for this, but the pure physics of the heat exchange between the combustion gases and the primary circuit says "make the primary circuit flow as cold as possible so that the combustion gases are cooled as much as possible". That would mean that the boiler is naturally at its most efficient when the hot water tank is stone cold, and the efficiency inevitably rolls off as the temperature rises in the tank.
Isn’t it to do with the secondary condenser in the flue for a condensing boiler?There may well be some good engineery reason for this, but the pure physics of the heat exchange between the combustion gases and the primary circuit says "make the primary circuit flow as cold as possible so that the combustion gases are cooled as much as possible". That would mean that the boiler is naturally at its most efficient when the hot water tank is stone cold, and the efficiency inevitably rolls off as the temperature rises in the tank.
I’ve had 2341L delivered in the last 12 months and I’m at around 200L left in the tank, first delivery was similar residual level @ €1622 give or take €135 pcm average although it has been very mild this winter
That’s for a four bed three bath 3K sq/ft house on the north west coast of Ireland where the oil does the water heating as well and isn’t particularly well insulated
I’ve also used three 1/2tonne bags of turf/blocks for the stoves which cost me around €200
It’s on a timer for a couple of hours in the morning/evening .. but more in winter but the fires once going can keep the house pretty toasty
That’s for a four bed three bath 3K sq/ft house on the north west coast of Ireland where the oil does the water heating as well and isn’t particularly well insulated
I’ve also used three 1/2tonne bags of turf/blocks for the stoves which cost me around €200
It’s on a timer for a couple of hours in the morning/evening .. but more in winter but the fires once going can keep the house pretty toasty
Edited by Earthdweller on Saturday 15th January 14:55
UnclePat said:
Circa 2,300 litres per year. 17-year old, four bed, three reception detached house. Northern but Coastal.
Roughly 2-3 litres daily in the height of Summer,
No electric showers, so the Oil heats the water too.
2-3 litres (20-30 kWhrs) of oil is enough to heat 4-500 litres of water each day, enough for a family of six.Roughly 2-3 litres daily in the height of Summer,
No electric showers, so the Oil heats the water too.
A hot water heat pump would use around 6 kWhrs to heat the same amount of water.
Burning oil is not a good way of heating water.
caziques said:
2-3 litres (20-30 kWhrs) of oil is enough to heat 4-500 litres of water each day, enough for a family of six.
A hot water heat pump would use around 6 kWhrs to heat the same amount of water.
Burning oil is not a good way of heating water.
Not really bothered. Northern climes, so as well as hot water for morning showers etc. a modicum of early morning radiator output is still welcome. Electricity at ~£0.23 per kWh or last tank fill at £0.53 per litre - it won’t keep me awake at night.A hot water heat pump would use around 6 kWhrs to heat the same amount of water.
Burning oil is not a good way of heating water.
3,600 sq ft 250 year old solid stone farmhouse/barn with 400sq ft glazed conservatory floor to ceiling and seven external doors 23 windows. All double glazed, roof insulated, 50% underfloor heated 50% radiators all done ten years ago running off a Worcester 18 - 24 Kw oil boiler which also runs one hour a day specifically to heat water tank for three bathrooms. So an under spec size oil boiler worked hard and daily even in summer for hot water.
Runs like a watch. Serviced every year and the engineer says it's amazingly clean and efficient. Uses 2000 litres in a mild winter year, 2400 in a cold winter year. Thermostats set to 22 degrees heating on for about five hours a day. When very cold (like now) we have three Clearview wood stoves in the kitchen, study and living room (wife works from home).
We are toasty and for the size and type of house I'm very pleased with the system (I did consider GSHP but woukd have cost £19k 11 years ago and that's using our own digger for the groundwork.
Seems like oil is cheap to me. And it works. And it's reliable.
I plan to buy a replacement oil boiler next year ahead of the ban on selling them so I can replace my Worcester. Possibly the same Greenstar model so the old one can be scavenged for parts in the future.
The boiler runs fine on Avtur (aviation kerosene) and they can't ban that...
Never giving up oil until the flux capacitor is invented!
Runs like a watch. Serviced every year and the engineer says it's amazingly clean and efficient. Uses 2000 litres in a mild winter year, 2400 in a cold winter year. Thermostats set to 22 degrees heating on for about five hours a day. When very cold (like now) we have three Clearview wood stoves in the kitchen, study and living room (wife works from home).
We are toasty and for the size and type of house I'm very pleased with the system (I did consider GSHP but woukd have cost £19k 11 years ago and that's using our own digger for the groundwork.
Seems like oil is cheap to me. And it works. And it's reliable.
I plan to buy a replacement oil boiler next year ahead of the ban on selling them so I can replace my Worcester. Possibly the same Greenstar model so the old one can be scavenged for parts in the future.
The boiler runs fine on Avtur (aviation kerosene) and they can't ban that...
Never giving up oil until the flux capacitor is invented!
The other half just nagged me to look at our oil usage as it's not really sustainable and need to look at alternatives as oil won't be getting any cheaper. We moved into our house (barn conversion) a couple of years ago and simply fill the 2000 litre tank when the Watchman tells me there's around 400-600 litres remaining.
From my quick Excel spreadsheet we used 5,350 litres in 2020 (average cost 35p/l) and 5,721 litres in 2021 (average cost 50p/l). We have 2 oil fired boilers, electric underfloor heating in our bathrooms and big log burner in the living room and a smaller one in the kitchen/snug, neither of which we really use to assist with the heating as it's a faff.
I read mixed reviews of heat pumps, both ground and air source, so not sure that's the solution for our kind of property. I doubt I'll get the pay back on solar to supplement the oil but would be happy to spend some cash to move away from oil.
Any thoughts
From my quick Excel spreadsheet we used 5,350 litres in 2020 (average cost 35p/l) and 5,721 litres in 2021 (average cost 50p/l). We have 2 oil fired boilers, electric underfloor heating in our bathrooms and big log burner in the living room and a smaller one in the kitchen/snug, neither of which we really use to assist with the heating as it's a faff.
I read mixed reviews of heat pumps, both ground and air source, so not sure that's the solution for our kind of property. I doubt I'll get the pay back on solar to supplement the oil but would be happy to spend some cash to move away from oil.
Any thoughts
It's tough at the moment. Some combination of solar + ASHP + batteries would let you charge at offpeak/sunny times, then use the stored power to run the ASHP. But the property has to be ASHP-compatible, at least.
I'm guessing it's stone walls, high roofs, old insulation, concrete floors? These sorts of properties are going to need significant retrofitting to be more energy efficient, many converted in a time when oil was cheap and CO2 wasn't on the radar.
Keep topping up the oil until electricity rates go down..if they ever do
I'm guessing it's stone walls, high roofs, old insulation, concrete floors? These sorts of properties are going to need significant retrofitting to be more energy efficient, many converted in a time when oil was cheap and CO2 wasn't on the radar.
Keep topping up the oil until electricity rates go down..if they ever do
Alex L said:
Any thoughts
Whilst this in only accurate to Oct last year, it should give you an idea as to what technology to consider or look at. I'm sure you can update it for the prices you can buy at.https://nottenergy.com/resources/energy-cost-compa...
I moved from oil to biomass back in 2017 but I also have my own supply of timber. I also need to consider the time it takes me to chop, stack, move etc - I don't do my own felling so there is a cost associated with that, albeit I'm still currently using trees felled during home / property / garden renovations - I use about 15m3 per year. My biomass boiler has the ability to have an auger pellet feed system added to it, so when I get too old / can't be bothered anymore, I can switch to bulk supplied pellets (once I've built a suitable pellet store....).
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