Free solar panel discussion

Cardew

ronlizpatsimon wrote: »

Googling indicates that I should halve my electric bill - which is £700 a year. Therefore £350 saved. Sounds rather optomistic to me but say it was only £150 and look at it as a percentage on the cost of installation and maintenance (with say "ashadegreener").
The answer if infinate% gain!

Sorry you have either misunderstood; or perhaps you could show the Google reference - because that is wrong!

If your bill was £1000 or £10,000 would your savings be £500 or £5,000?

Some years ago when PV panel systems were generally smaller, the 'rule of thumb' was that 50% of the electricity generated could be used in the house. Thus it is assumed for the owners of the panels that the other 50% is exported and they are paid 3p/kWh for those units(they obviously get the 41.3p/kWh for all units generated.)

It is only possible to work out accurately how much electricity you use in the house if you have an export meter; which I believe none of the 'rent a roof ' companies fit. e.g generated 2,000kWh exported 1500kWh(as measured by export meter) so 500kWh used in house.

All the indications are that the 50% usage in the house is difficult to achieve with larger systems. Two people on MSE who have got export meters and have had systems for years use 500kWh(worth about £50) and 1,000kWh(£100) pa. The poster using 500kWh has wife and two small children at home all day.

The larger A Shade Greener(ASG) system is 3.3kWp and they expect 2,800kWh pa to be generated. There is a long thread in the green section about ASG and one of their Directors did not dispute £100 a year would be a reasonable; that figure is also in line with that used by WHICH. ASG incidentally appear to be a very good firm.

So IMO and many others you can reasonably expect to save between £50 and £100 a year. If you have gas CH then it might well be a lower saving as using the solar power to heat water with an immersion heater could turn out to lose you money(explanations given earlier) on water heating.

So it boils down to whether you consider the potential rewards are worth the potential disadvantages of restrictions on your house for 25 years.

ronlizpatsimon

"Cardew", you asked me what I thought my savings would be if my electric bill was (without panels) £1000 a year and £10000 a year.

The 50% rule only applies on the £1000 bill, so the savings in cash would be the same on the £10000 bill. The reason for that is that on a "normal" domestic panel installation; (max 4kw) the panels could not produce any extra power. e.g. savings cannot exceed the solar power you produce (and use), times the cost of that usage if you had paid the currently normal 12p a unit

Cardew

ronlizpatsimon wrote: »

"Cardew", you asked me what I thought my savings would be if my electric bill was (without panels) £1000 a year and £10000 a year.

The 50% rule only applies on the £1000 bill, so the savings in cash would be the same on the £10000 bill. The reason for that is that on a "normal" domestic panel installation; (max 4kw) the panels could not produce any extra power. e.g. savings cannot exceed the solar power you produce (and use), times the cost of that usage if you had paid the currently normal 12p a unit

Not understood!

This is what you wrote:

Googling indicates that I should halve my electric bill - which is £700 a year. Therefore £350 saved

What site does Google bring up that states what you say in that quote?

ronlizpatsimon

Cardew, you asked for a google reference to justify what I said about a reference to getting 50% of my bills covered. This time I did not find one that said 50%. However if you fully read the following link http://www.guardian.co.uk/money/2010/aug/14/free-solar-panels you will see one example of a 30% reduction of cost and another of 60%. Was there any other part of my last post, with the calculation in, which you did not understand (or agree with)?

Cardew

ronlizpatsimon wrote: »

Cardew, you asked for a google reference to justify what I said about a reference to getting 50% of my bills covered. This time I did not find one that said 50%. However if you fully read the following link http://www.guardian.co.uk/money/2010/aug/14/free-solar-panels you will see one example of a 30% reduction of cost and another of 60%. Was there any other part of my last post, with the calculation in, which you did not understand (or agree with)?

I am afraid that is quite typical of what passes for journalism these days.

Just quote what a Homesun salesman states.

The Case Study is wonderful:

"It was all very painless and the savings have been good. We pay for our electricity using a keycard which we load at the local shop. I used to be putting £15-£20 a week on it, now it's closer to £5.


She is now planning to turn off the central heating in winter, and to try and use an electric heater to take advantage of the free electricity.

You couldn't invent it!!!!

zeupater

ronlizpatsimon wrote: »

Cardew, you asked for a google reference to justify what I said about a reference to getting 50% of my bills covered. This time I did not find one that said 50%. However if you fully read the following link http://www.guardian.co.uk/money/2010/aug/14/free-solar-panels you will see one example of a 30% reduction of cost and another of 60%. Was there any other part of my last post, with the calculation in, which you did not understand (or agree with)?

Hi

If you think about it you'd take some of the information in that, and many other articles, with a pinch of salt.

I take it that the 60% reduction you mention is based on consumption reducing from £15/week to £5/week ... this is possible over the short term in mid summer, but cannot be sustained at this rate throughout the year. A £10/week reduction is £500/year, or 5000kWh/year .... I think that you will agree that it is unlikely that it is realistic that the example referenced would really be a household with a non-E7 usage of 7500kWh/year, and that a 'rent-a-roof' array is unlikely to produce 5000kWh/year, whatever the salesmen may say.

Always question such claims

HTH
Z

ronlizpatsimon

Yes "zeupater" , I agree the Guardian figures are likely to be optimistic. However; whatever you save on previous bills is all profit (with a fully free installation/maintenance package). Except for the cups of tea for the installers!

Cardew

ronlizpatsimon wrote: »

Yes "zeupater" , I agree the Guardian figures are likely to be optimistic. However; whatever you save on previous bills is all profit (with a fully free installation/maintenance package). Except for the cups of tea for the installers!

So it all boils down to:

whether you consider the potential rewards are worth the potential disadvantages of restrictions on your house for 25 years.

If you made 50 pence a year it would still be 'all profit';)

ronlizpatsimon

"Cardew", I do not remember noticing any restrictions on the house roof with a free installation (as apposed to a paid for installation).
No doubt you will enlighten me!

John_Pierpoint

John_Pierpoint wrote: »

In my experience of selling a Victorian house (which would be a money pit of insulation nightmares as it was a typical terrace shape but it was detached) the answer is NO.
Of the dozen serious viewers not one asked for the HIP or EPC.
The £45 quid EPC was very formulaic (ie tick the boxes) and did not appear to take account of the fact that the house was long and thin.
(Roughly 14 ft wide and 45 ft long with solid walls and suspended floors).

HOWEVER all these EPC are being fed into a European wide data base and will be available for use as carrot information, for RHI purposes; and stick information, when it comes to refurbishment and future carbon taxation.

(Who would have thought 20 years ago that cars would be taxed on their carbon emissions:rotfl:)

To answer my own question "Does having solar panels on the roof make a difference to the rating of the house in the Energy Performance Certificate?" The answer is YES.

Here is the list of changes made to the EPC procedure effective April 2011 (Based on the Standard Assessment Procedure - SAP updates effective October 2010.
The SAP is the method for calculating the energy requirement of a building in the quest for a zero home - as in "Z-bed" development in S. London).

http://www.bre.co.uk/filelibrary/SAP/2009/Reduced_Data_SAP_2009_for_April_2011.pdf

This could be a valuable additional reason for putting PV panels on your roof, when the government introduces the stick as well as the carrot - a bit like owning a car with very low emissions and paying no road tax.

John

PS. The Victorian house had a roof ridge running North - South