Site Prices Update
Last Updated28th June 2022
All calculations on this site are based on current fuel prices, they are checked regularly and calculations are automatically updated.
The costs calculated based on these fuel prices should be regarded as 'good estimates', given that fuel prices vary in different parts of the county and at different time of the year.
The calculations also have different levels of accuracy depending on the nature of the calculation. For example calculating the energy use of a known power output TV is very easy compared to calculating the effect on energy savings when insulating a cavity wall.
Site Calculations
Set Your Own Prices
User PricesFor several of the fuel prices on this site you can now set your own prices and all the calculations on the site will adjust accordingly.
Set Prices
At Confused About Energy we aim to provide practical, impartial advice on all aspects of energy usage, climate change and ways to save money on energy bills.
All calculations on this site are based on current fuel prices they are checked regularly are automatically updated and were last changed on:-
28th June 2022
The costs calculated based on these fuel prices should be regarded as 'good estimates', given that fuel prices vary in different parts of the county and at different time of the year.
The calculations also have different levels of accuracy depending on the nature of the calculation. For example calculating the energy use of a known power output TV is very easy compared to calculating the effect on energy savings when insulating a cavity wall.
Site Calculations
Electricity | £0.271 per unit (1 kWh) |
Economy Electricity | £0.094 per unit (1 kWh) |
Gas | £0.072 per unit (1 kWh) |
Domestic LPG | £0.122 per unit (1 kWh) |
Heating Oil | £0.104 per unit (1 kWh) |
UK Grid CO2 Emissions | 0.233 kg per kWh used |
The main units used in this site are in the table below, For a complete explanation of power and energy Read More.
Unit | Name | Detail |
---|---|---|
W | Watt | Unit of Power |
kW | Kilowatt | 1000 watts |
kWh | Kilowatt hour | Measure of Energy |
L | Litre | Measure of Volume |
Please use twitter to ask a question Message @@EnergyThinking

Cost: High
ROI: 34.7 Years
Skill: Specialist
Energy Saving: Medium
CO2e Saving: Medium
|
ROI is the time it takes to return the investment in fuel savings for an average gas heated 3 bed semi-detached house and assumes no government incentive schemes are used: Years
How easy this is to do: DIY-Easy : DIY-Skilled : Specialist
How much energy will be saved with this measure: Low : Medium : High
How much Carbon Dioxide emission will be saved with this measure: Low : Medium : High
...assuming this is the only insulation measure installed in your house you should reduce your overall energy bill by between 5% and 10%.
For the smaller 3 bed house assuming you save the maximum 10% of your heating costs you should save £70 each year if you are gas heated and if it cost about £5000 to install the windows the investment will payback in about 70 years.
The payback for this investment is long! If however you are replacing old windows and generally upgrading your property it is very well worth doing, or if you are just sick of the constant drafts next to your old windows. Also a pure pay back figure for double glazing does not account for the increased value of your property, so the figures in the table do perhaps present a more negative picture than double glazing deserve, however the best case scenario of 10% savings is presented in the tables together with the associated carbon dioxide emission reductions
Financial savings by installing double glazing - per year CO2e emission reduction - kg per year |
Below average energy use for heating per year smaller house or warmer area |
Average energy use for heating per year the average in the UK |
Above average energy use for heating per year larger house or colder area |
|
Source of energy for heating | Savings with original energy use 10000 kWh |
Savings with original energy use 15000 kWh |
Savings with original energy use 20000 kWh |
Savings with original energy use 25000 kWh |
⚡ Electricity £0.271 per kWh |
£271 (233kg) | £406.5 (349.5kg) | £542 (466kg) | £677.5 (582.5kg) |
⚡ Gas £0.072 per kWh |
£72 (210kg) | £108 (315kg) | £144 (420kg) | £180 (525kg) |
⚡ Off Peak Electricity £0.094 per kWh |
£94 (233kg) | £141 (349.5kg) | £188 (466kg) | £235 (582.5kg) |
⚡ LPG £0.122 per kWh |
£122 (240kg) | £183 (360kg) | £244 (480kg) | £305 (600kg) |
⚡ Heating Oil £0.104 per kWh |
£104 (300kg) | £156 (450kg) | £208 (600kg) | £260 (750kg) |
Source of energy for heating | Glazing install costs select yours. |
Payback time with original energy use 10000 kWh (years) |
Payback time with original energy use 15000 kWh (years) |
Payback time with original energy use 20000 kWh (years) |
⚡ Electric £0.271 per kWh |
£5000 £6000 £7000 £8000 £9000 | 18.5 22.1 25.8 29.5 33.2 | 12.3 14.8 17.2 19.7 22.1 | 9.2 11.1 12.9 14.8 16.6 |
⚡ Gas £0.072 per kWh |
£5000 £6000 £7000 £8000 £9000 | 69.4 83.3 97.2 111.1 125 | 46.3 55.6 64.8 74.1 83.3 | 34.7 41.7 48.6 55.6 62.5 |
⚡ Economy Electric £0.094 per kWh |
£5000 £6000 £7000 £8000 £9000 | 53.2 63.8 74.5 85.1 95.7 | 35.5 42.6 49.6 56.7 63.8 | 26.6 31.9 37.2 42.6 47.9 |
⚡ LPG £0.122 per kWh |
£5000 £6000 £7000 £8000 £9000 | 41 49.2 57.4 65.6 73.8 | 27.3 32.8 38.3 43.7 49.2 | 20.5 24.6 28.7 32.8 36.9 |
⚡ Heating Oil £0.104 per kWh |
£5000 £6000 £7000 £8000 £9000 | 48.1 57.7 67.3 76.9 86.5 | 32.1 38.5 44.9 51.3 57.7 | 24 28.8 33.7 38.5 43.3 |
Below is a typical statement regarding double glazing, from a well known energy saving website and it is frankly complete nonsense, please be aware of comments like this.
“ It is estimated that in an average dwelling the capital cost of replacement windows will pay for itself in energy savings within six years”
If this were true then for natural gas users your heating bill would have to have been over £1000 per year and that by fitting double glazing you would suddenly no longer need to heat your house at all. We all know this is not true. However the below represents good and responsible advice from a UK council web site (Eastleigh).
"While windows themselves lose heat quickly through the glass, as the overall area of window is small compared to other surfaces of your house (such as the walls), they only account for 5-10% of the heat lost from your home.
Double glazing has become very popular in recent years. As it is relatively expensive and the amount of heat saved fairly small, you may not wish to consider it for energy saving reasons alone. Good draught proofing and thermally lined curtains can significantly cut heat loss and will cost much less.
Double glazing is popular for other reasons such as security, noise reduction and reduced maintenance. You need to weigh up all these factors before replacing your windows.
Under current building regulations, when replacing windows they must be fitted with low emissivity glass (sometimes called 'low-E' or 'K-glass'). You should look for a FENSA registered installer to make sure the windows are fitted to building regulation standards.
Further things to consider:
• uPVC (plastic) windows do not last forever. They represent a large waste disposal problem as they do not break down. The manufacture of uPVC also uses large amounts of energy.
• A number of manufacturers offer timber framed double glazed windows which are a more sustainable alternative."
With energy prices increasing. Money saving expert are quoting the Typical bill rising in April 2023 to £6,616/yr for the "average" household. It would be interesting to re-calculated cost benefit analysis now.
With energy prices increasing. Money saving expert are quoting the Typical bill rising in April 2023 to £6,616/yr for the "average" household. It would be interesting to re-calculated cost benefit analysis now.
It is also a great in reducing noise from outside!
well there is no arguing with that!
Good advice from Eastleigh Borough Council. This was 100% true before Low E glass and argon filling of the glazing. However: I have just had to replace my windows and have used "A" rated glazing all round including a conservatory. Modern windows are now so efficient that there is NEVER any condensation on the inside! Even in the 2010/11 winter. Reflective glass also radiates heat back into the room, so raising the radiant environmental temperature. The result is that you are comfortable at a lower AIR temperature. Therefore your heating can be turned down a degree which is a hidden benefit of all insulation. Always use a programmable room thermostat to make use of savings.
Do you have any data that quantifies this observation. I can believe they are improving, but a financial justification on energy grounds requires and understanding of how much better and I doubt it is more than a few percent. This is not the case:- "Therefore your heating can be turned down a degree which is a hidden benefit of all insulation"- although I understand what you mean. In most houses the thermostat will be set at the same temperature with any added insulation measure, but because the heat loss is lower the thermostat will trigger the boiler to switch on less regularly and will therefore save money and energy.
This is a great piece of information about energy saving double glazing. At Cheshire uPVC Double Glazing http://www.cheshire-upvc.co.uk we are always looking to use the most energy efficient glass, and currently have A rated glass available.
And guess what? You can actually now get very thin glass (Pilkington) that has the same thermal properties as the standard double-glazing; so all you have to do is get the glass replaced in your windows, rather than ripping the windows out. Not many people know that.....well of course not, the dg companies want to flog you a complete window, don't they? It would be ideal for period properties, retain the wooden windows and maintain traditions.
Comments and Questions