Switching gas heating/water to oil heating/water - good idea?

What_time_is_it

For someone with a very high gas usage for heating and hot water (about 60,000 kwhs a year), would it be a good move to switch to oil instead?

This is for an elderly relative. We are looking at updating her heating system and were originally thinking of a new gas boiler. Someone mentioned oil as an alternative and it does currently seem cheaper than gas. 

What do you think? Is it a good way to go?

victor2

Gas has always traditionally been the cheapest method of heating. Even with the latest price rises, I believe it still is.

Installing an oilf fired boiler would be very expensive and messy, with the need for a tank somewhere.

Look at gettting more useful controls for her heating, possibly "zoning" her property if that makes sense. Does she have a very old boiler and water tank? Would switching to a combi or just getting a new more efficient boiler and improving the hot water supply help?

What_time_is_it

Thanks @victor2
All good advice. Better controls is an absolute must. It's either on (heating AND water) or off. And in winter it is on. All the time.

Alnat1

Using predicted costs, that's £9000 a year for gas!

If a new boiler and tank were fitted with timer, TRVs and room thermostat they are going to pay for themselves in a very short time, possibly not much more than a year.

lohr500

I don't have gas so I'm not up to speed with the predicted October price.
But I do have an oil boiler and I am a big fan of them.

Alnat1's comment suggesting that 60,000kwh of gas will cost £9000 a year, equates to £0.15 per kwh.

A litre of kerosene heating oil in my area of Yorkshire, currently costs £0.88, including the 5% VAT.
One litre of heating oil yields 10.35kWh at 100% conversion efficiency.
So that works out at £0.084 per kwh.

With a modern oil boiler efficiency of say 90% (Ours claims to be 94.5%), this would result in a cost of £0.093 per kWh.

On this basis, using the current oil price and Alnat1's suggested October gas price, gas will be 61% more expensive than oil.

Using the same values, 60,000 kwh would cost £5580 in oil vs £9000 in gas. An annual saving of £3420.

Last year it cost us just over £5000 to have our old 36kW oil boiler replaced with a modern external Grant unit (with 10 year Grant parts and labour warranty ). And the year before it cost us £2400 to have a new double skinned 2500 litre oil tank and concrete base installed. (This to replace a damaged single skinned tank on an unsafe base). 
The boiler install involved rerouting some pipework and changing the system from gravity hot water circulation to a valve controlled Y plan layout which has also helped with efficiency.

If you took the combined costs of the boiler and tank installs and said £7500, then I guess replacing a gas system would be similar costs or a bit less if you needed a smaller boiler.

Payback = £7500/3420 = 2.2 years.

Heating oil prices have softened a little in the past few weeks, but who knows what will happen in the next 18 months and beyond.

Also you would need to consider if there is a suitable location for an oil boiler and tank, the risk of oil theft and if gas is also used for cooking. Some house buyers may also be put off by oil heating, although it wouldn't concern me in the slightest.

If it was me, even though I could see a good saving switching to oil right now, I think I would stick with gas. And then, as others have suggested, look at ways to reduce consumption through better controls and possibly extra loft insulation etc.


What type and model is the existing gas boiler? You can check the theoretical efficiency on this website.

https://www.homeheatingguide.co.uk/efficiency-tables

Unless it is a very old gas boiler and in poor condition, replacing it with a new gas boiler may not significantly improve efficiency, so the money could well be better spent on controls and insulation. 

Mister_G

Then there is bulk LPG.  Currently costing 6.2p/kWh.  The boilers are much cheaper than oil boilers and need less maintenance.

lohr500

Wow. Is that 6.2p/kWh on a never to be repeated fixed contract or the current spot price? When I last looked at LPG it was more expensive than oil.

markin

From skimming the post history, The boiler is 40+ years old and so 60% efficient? Any new boiler would probably half the energy usage and pay back in a year, Then the is cutting the water heating down say 80% just by controlling it with a timer.

Switching to oil would be a terrible idea, apart from the advantage of buying it a little bit cheaper in the summer, the install cost is far larger £6k just for the tank?

k_man

markin said:

From skimming the post history, The boiler is 40+ years old and so 60% efficient? Any new boiler would probably half the energy usage and pay back in a year, Then the is cutting the water heating down say 80% just by controlling it with a timer.

Switching to oil would be a terrible idea, apart from the advantage of buying it a little bit cheaper in the summer, the install cost is far larger £6k just for the tank?

Workings out please?
In my maths, unless the new boiler is 120% efficient it can't use only half the energy?
Unless you are including improved controls too.

Agree about oil being a dangerous move though, even without the install cost, as I think we can all guess what direct oil costs will go as gas goes up.

markin

lohr500 said:

Wow. Is that 6.2p/kWh on a never to be repeated fixed contract or the current spot price? When I last looked at LPG it was more expensive than oil.

The are many people saying fixed contracts aren't being honoured.

markin

k_man said:

markin said:

From skimming the post history, The boiler is 40+ years old and so 60% efficient? Any new boiler would probably half the energy usage and pay back in a year, Then the is cutting the water heating down say 80% just by controlling it with a timer.

Switching to oil would be a terrible idea, apart from the advantage of buying it a little bit cheaper in the summer, the install cost is far larger £6k just for the tank?

Workings out please?
In my maths, unless the new boiler is 120% efficient it can't use only half the energy?
Unless you are including improved controls too.

Agree about oil being a dangerous move though, even without the install cost, as I think we can all guess what direct oil costs will go as gas goes up.

It likely has a pilot burning, That's not included in the burning efficiency number is it?  But yes including controllers, Many boilers claim over 100% efficient.