A Shade Greener Solar Energy Usage Study 2011

We surveyed 100 of our customers a year after having their free solar panels installed. The survey asked a series of questions to determine their electrical energy usage at home and asked about how much they had saved on their energy bills. Of the 100 households surveyed 90 provided us with information about their energy usage, the vast majority of these provided proof with actual bills.

As there is no reliable public data available to show fuel savings for residential properties a study of our customers was commissioned to discover the actual amount typical households with solar panels could save over a year. A Shade Greener wanted to know by how much you could actually reduce your electricity bills by and whether having solar installed changed the way people think about their energy usage.

How to read this data

The graphs and data illustrate the average savings customers with our free solar panels installed made on their electricity bills compare to the previous year. All percentages are averages of the compared sample data, all figures in brackets (n) represent the number of respondents for each answer.

Study highlights

• Average savings of 37% on electric bills with free solar installed
• Changing your electricity usage habits helps cut your bills
• Everyone installing solar saved on their energy bills

Distribution of savings on electricity bills displayed as a percentage.

The study highlights that a majority of customers managed to make a saving of at least a third of their electricity bills compared to the previous year. The comparison was made by comparing the amount the customer paid on their energy bills with the previous year prior to having the panels installed. The customer supplied either their annual consumption figures in kilowatt hours or the amount they actually paid on their bills. Figures that were supplied as actual bill figures rather than annual consumption figures have not been adjusted to take account of any energy price rises over the same period. This means that the savings may have been slightly higher for those submitting bill payment figures.

What is your employment status?

• Full time (44) had an average saving of 37%
• Retired (31) had an average saving of 36%
• Part time (9) had an average saving of 41%
• Not working (4) had an average saving of 45%
• Other (2) had an average saving of 52%

Percentage energy savings by employment status.

Employment status was compared to actual savings made on the customers bills. The sample figures for part-time, not working and unknown are not large enough to make any general statements about how occupation affects usage. The sample data for full-time and retired is larger but does not seem to indicate any difference in savings whether you are retired or work full-time.

The percentage energy savings based on employment status and change in usage habits.

We can only speculate to the reasons for this but the figures for householders changing their usage habits tend to suggest that this may be a stronger factor than employment. When you compare both those retired and those in full-time employment along with the data that shows whether they changed their energy usage habits there does seem to be a clear correlation. The data shows that it is not your employment status that has the major impact on your energy savings but whether or not you change you usage habits to take better advantage of the free solar power being generated.

Is the home occupied during the day?

• At home during the day (50) saved 39%
• Partly home during the day (26) saved 37%
• Not at home during the day (14) saved 36%

The percentage of energy savings made based on the amount of time spent at home during the day.

When comparing energy savings against daytime home occupation the assumption would have been that those spending more time at home during the day would save more as they would be able to use more of the available solar electricity. The figures do not seem to reflect this, in fact whether you are at home during the day only seems to have a small impact on energy savings.

Number of occupants in the household

• One occupant households (5) with average savings of 27%
• Two occupant households (48) with average savings of 38%
• Three occupant households (14) with average savings of 44%
• Four occupant households (14) with average savings of 35%
• Five occupant households (6) with average savings of 41%
• Households occupation not specified (3) with average savings of 36%

The savings on energy bills made based on the number of people occupying the house.

A majority of the homes with solar installed were two occupant households reflecting the number of customers who are retired. This may also indicate a large number couples of whom may have not yet retired but where the children have left home. The next largest sample is three and four occupant households that would indicate family units. There does not seem to

be any obvious pattern between the number of people in a particular household and the amount of savings the occupants have made through installing solar.

Households that changed their electricity usage habits

• Yes (66) saved an average of 40%
• No (24) saved an average of 31%

Savings made based on the occupants change in energy usage habits.

As expected those households who have stated that they have actively changed their electricity usage habits did on average save more on their electricity bills. This may be due to the homeowners being more aware of how much energy they were actually using and having a financial saving incentive to use as much of the free daytime electricity as possible. People on average saved a third on their electricity bills with no lifestyle changes, were people changing their energy usage habits on average reduced their bills by 40%.

Conclusion

We can conclude from the sample of customers that responded to our survey that you will save on your energy bills by installing solar. We could extrapolate that similar savings would be made if you had purchased your own solar pv system as the incentive to use the free electricity would be the same.

Whilst the average amount that you would save is 37%, just over a third on your energy bill, there is evidence to suggest that you could save more than the average if you actively changed your usage habits. In practice this would mean using domestic appliances where possible during the day rather than at night. The type of appliances that typically use a lot of electricity are tumble dryers, washing machines, electric ovens, electric heaters, electric irons and air conditioning units. By setting these devices with timers to come on during daylight hours or using these appliances before or after works during the longer summer months you can use more of the available free daytime electricity from your solar panels.