Solar Heating - grant aid and advice?

bridiej

This may be of assistance http://www.ecs-solar.com/solarhotwater_faq.htm

It's a US site, but they say around 5 years to get back what you've paid out... of course I would guess it depends on how much sun you get.

Cardew

QUOTE=jimbob]having read this thread i'm not sure that i am much clearer than before...


can anybody, in very simple terms show me a comparison between what i have now, the cost and saving of a new combi boiler and the cost and saving of putting in some kind of solar panels etc

.....
thanks[/QUOTE]

In simple terms there is no way that solar panels make any form of financial sense. If you feel by getting them you are doing your bit for the environment - go ahead; but be very clear that you will be paying heavily for that 'feel good' factor.

Solar panels only provide domestic hot water,(DHW) not central heating. Calculate how much gas/electricity/oil you use for DHW(not CH) if you can. The average is £100-£150 a year. Even with the best systems you will be lucky to save 50% of that.(Yakky58 in the post above states 30%)

So you are likely to save between £30 and £75 a year for an investment of ?? Yakky 58 paid £2,600 even installing it himself. Now you don't need to be an economist to work out that investing that sort of money for those sort of savings makes no financial sense.

We haven't even begun to talk about servicing and repair costs for the pump and electronics - or the cost of running the pump.

As for some of the adverts from firms - they verge on criminal.

So Solar panel Hot Water heating is a very poor investment; however compared to solar panel electricity generation it is brilliant value.

tabath

I reckon well under a grand could get you a decent set up using panels from navitron

Skiduck

to see how efficient your boiler is and the possible savings on replacing your boiler:

http://www.sedbuk.com/cgi-local/searchpg.cgi

yakky58

Just some updates. On servicing costs, and i have to take the manufacturers word the pump should last as long as central heating pump. I have never replaced my central heating pump in 11 years so the cost will be low. The electronics is 10 year guarantee. So I am not overly bothered.

As June has been hot, compared to May the solar was very efficient. You have to make a life style change and shower after the sun is up. That's not so hard to do. My boiler is 23 years old, serviceable but not efficient. yes I agree the return on investment is long and maybe never recoverable.

On solar electricity generation. Just had my bill. Generated 589 Kwh (over 1/2 a mega watt). Drew 529 units from the grid exported 290 that's over 50% savings. So I am more convinced now. Some days exported more than I drew which means goodness. All this in 63 days and lots of days poor weather. So I believe you can make savings....don't expect it can pay for itself in the short term. Long term maybe but benefit to environment also has to be taken into account.

Simon_Wilkinson

I have looked into installing solar panels on my house (photovoltaic systems that generate electricity) and was frustrated by the cost. Even with Govt. grants the pay-back time is too long. I am now trying to do something about this and have set up a website

https://www.sunroofenergy.org

where like-minded people can register their interest. In parallel, I am in discussions with solar panel companies in order to negotiate reduced prices - providing I can demonstrate sufficient demand. I am also trying to challenge the Govt in waiving their 50% limit on their grants so that any price reductions I can secure are passed all to the consumer. It is early days yet & I need all the support I can get. This is NOT a business venture - I am just an ordinary member of the public who wants to do his bit for the environment - if the price is right! Please help me to get this off the ground so that better use of solar energy can be made. There's no obligation when you register on my website, it's just a show of hands at the moment.:cool2:

mrmister_3

Regarding the energy savings and payback of solar, this is how I would determine and calculate the savings I will be deliberately conservative in my figures although I am sure you will reap greater benefits:

The following is relatively straight forward but I have tried to explain each step and how I arrived at the figures used which is why it may appear rather complicated.

http://www.whatprice.co.uk/utility/gas-bills-utility.php as a basis for a gas bill 3 bed detached home average gas bill is £778 yearly total 25% of this would be for hot water requirements approximately £195 /year

Overall yearly hot water requirements can be supplied by solar up to 60 - 70% this is made up from 100% in the summer, 60% in spring and autumn and 20% in the winter. therefore we have 250% / 400% giving an average of 62.5% for the year. But lets take a conservative view of 50% as it depends also on your geographic position in the UK as well as local weather patterns and efficiency of system installed.

So we have 50% of hot water needs supplied by solar the average house hold gas bill is £195 *50% = £97 approximately £100 per year saving as a minimum.

Gas bills are rising they are predicted to rise again around the New Year, Gas is a finite resource and will run out we can only expect gas prices to continue to rise.
In the last 3 years they have doubled, if we assume modest 10% rises each year then by year 10 in hot water alone you would be saving £259 a year and a total saving of £1753 over 10years based on a 50% efficient solar system.

1 2 3 4 5 6 7 8 9 10 - Years
£ 110.00 £ 121.00 £ 133.10 £ 146.41 £ 161.05 £ 177.16 £ 194.87 £ 214.36 £ 235.79 £ 259.37


if achieving a 70% solar efficient system then it would be saving you £363 in year 10 and a total of £2454 over 10 years

1 2 3 4 5 6 7 8 9 10 -Years
£ 154.00 £ 169.40 £ 186.34 £ 204.97 £ 225.47 £ 248.02 £ 272.82 £ 300.10 £ 330.11 £ 363.12



As you can see from the above depending on the efficiency of the system you will make savings over 10 years of around half the cost of £4000 - £4500 installation at around £2000

There are other factors to consider, the boiler will be operating less often which means its life expectancy should be higher, and the cost of operating it should be lower.
In simplistic terms if the average cost of owner ship, parts labour (averaged over 10 years) were £100/ year for a boiler we could potentially be saving £20 of that cost, over 10 years a £200 saving

We would expect the boiler to last around 20% longer(its being used less) the average life of a boiler is 5 to 10 years, take 10 years as a best case scenario and a average boiler at £1000 is £100/year Again a saving of £200


All the above figures are based on heating the water to the required temperature 60c, but even on a cloudy wet day there will be some solar output and this will be warming the water by a few degrees, every degree raised is a saving of gas being burnt to raise it that degree. A 10 degree rise in water temperature will save 15% of energy required to raise it that 10 degrees.

Install a thermal store instead of a solar cylinder and any solar gain will contribute to the the whole heating requirements not just the hot water.
Using a thermal store also allows the water temperature to be in excess of that required (60c) and with a convential vented thermal store the dangers of over heating are simply contained with out the associated cost of annual maintenance of unvented cylinders. The mains fed hot water can be regulated thermostatically to 60c allowing the tank to be any temperature above this to an upper limit of 85c which means an increase in the amount of hot water that can be acheived from the store.
Back to space heating- if we save only 10% of the energy required to raise the heating system from cold we would be saving on the main bulk of the gas bill.

Taking just a 10% saving of overall heating £778 - £195 =£583 (this is the portion of heating as based on the calculation for annual gas usage used earlier) 10% of £583 = £58

using the same calculation as above with a 10% increase in energy per year would save over the 10 years a total of £1016

1 2 3 4 5 6 7 8 9 10 -Years
£ 63.80 £ 70.18 £ 77.20 £ 84.92 £ 93.41 £ 102.75 £ 113.03 £ 124.33 £ 136.76 £ 150.44



we are now looking at a total saving of £2000 +£200 +£200 +£1016 = £3416 and this I believe is a conservative figure.


Interesting thought? solar is one of the only heating systems that will pay for itself and save you money certainly over 15 years and possibly within 7. A gas /oil boiler will never pay back, it will always continue to cost money, yet we never look for a payback on it..?
We never look at the cost of interest in providing gas and oil heating systems rarely look at the ongoing costs of the ownership of such systems.


Comments please !!

penrhyn

Two things come to mind, solar water heating dosn't work in the winter when you need to heat the house, and what do you need gallons of hot water for in the summer when you want to keep cool.
O and one more thing, no-one ever considers the benefits of climate change, its getting warmer so our heating requirements should start coming down.
Now where can I hire a punka wallah.

mrmister_3

penrhyn wrote:

Two things come to mind, solar water heating dosn't work in the winter when you need to heat the house, and what do you need gallons of hot water for in the summer when you want to keep cool.

Solar can be used to run airconditioning but you would need a different system and much higher storage temperatures at steam temperature.

Solar heating does work in winter, it is simply much less reliable and lower efficiency but it will still heat water on a cloudy day and therefore contribute to warmer water at the store thereby requiring less boiler input to raise the water temperature, and on clear day it will work very well.

Our predicted climate change is for a warmer but wetter climate with colder winters.

Cardew

mrmister wrote:

Regarding the energy savings and payback of solar, this is how I would determine and calculate the savings I will be deliberately conservative in my figures although I am sure you will reap greater benefits:

The following is relatively straight forward but I have tried to explain each step and how I arrived at the figures used which is why it may appear rather complicated.

http://www.whatprice.co.uk/utility/gas-bills-utility.php as a basis for a gas bill 3 bed detached home average gas bill is £778 yearly total 25% of this would be for hot water requirements approximately £195 /year

Overall yearly hot water requirements can be supplied by solar up to 60 - 70% this is made up from 100% in the summer, 60% in spring and autumn and 20% in the winter. therefore we have 250% / 400% giving an average of 62.5% for the year. But lets take a conservative view of 50% as it depends also on your geographic position in the UK as well as local weather patterns and efficiency of system installed.

So we have 50% of hot water needs supplied by solar the average house hold gas bill is £195 *50% = £97 approximately £100 per year saving as a minimum.

Gas bills are rising they are predicted to rise again around the New Year, Gas is a finite resource and will run out we can only expect gas prices to continue to rise.
In the last 3 years they have doubled, if we assume modest 10% rises each year then by year 10 in hot water alone you would be saving £259 a year and a total saving of £1753 over 10years based on a 50% efficient solar system.

1 2 3 4 5 6 7 8 9 10 - Years
£ 110.00 £ 121.00 £ 133.10 £ 146.41 £ 161.05 £ 177.16 £ 194.87 £ 214.36 £ 235.79 £ 259.37


if achieving a 70% solar efficient system then it would be saving you £363 in year 10 and a total of £2454 over 10 years

1 2 3 4 5 6 7 8 9 10 -Years
£ 154.00 £ 169.40 £ 186.34 £ 204.97 £ 225.47 £ 248.02 £ 272.82 £ 300.10 £ 330.11 £ 363.12



As you can see from the above depending on the efficiency of the system you will make savings over 10 years of around half the cost of £4000 - £4500 installation at around £2000

There are other factors to consider, the boiler will be operating less often which means its life expectancy should be higher, and the cost of operating it should be lower.
In simplistic terms if the average cost of owner ship, parts labour (averaged over 10 years) were £100/ year for a boiler we could potentially be saving £20 of that cost, over 10 years a £200 saving

We would expect the boiler to last around 20% longer(its being used less) the average life of a boiler is 5 to 10 years, take 10 years as a best case scenario and a average boiler at £1000 is £100/year Again a saving of £200


All the above figures are based on heating the water to the required temperature 60c, but even on a cloudy wet day there will be some solar output and this will be warming the water by a few degrees, every degree raised is a saving of gas being burnt to raise it that degree. A 10 degree rise in water temperature will save 15% of energy required to raise it that 10 degrees.

Install a thermal store instead of a solar cylinder and any solar gain will contribute to the the whole heating requirements not just the hot water.
Using a thermal store also allows the water temperature to be in excess of that required (60c) and with a convential vented thermal store the dangers of over heating are simply contained with out the associated cost of annual maintenance of unvented cylinders. The mains fed hot water can be regulated thermostatically to 60c allowing the tank to be any temperature above this to an upper limit of 85c which means an increase in the amount of hot water that can be acheived from the store.
Back to space heating- if we save only 10% of the energy required to raise the heating system from cold we would be saving on the main bulk of the gas bill.

Taking just a 10% saving of overall heating £778 - £195 =£583 (this is the portion of heating as based on the calculation for annual gas usage used earlier) 10% of £583 = £58

using the same calculation as above with a 10% increase in energy per year would save over the 10 years a total of £1016

1 2 3 4 5 6 7 8 9 10 -Years
£ 63.80 £ 70.18 £ 77.20 £ 84.92 £ 93.41 £ 102.75 £ 113.03 £ 124.33 £ 136.76 £ 150.44



we are now looking at a total saving of £2000 +£200 +£200 +£1016 = £3416 and this I believe is a conservative figure.


Interesting thought? solar is one of the only heating systems that will pay for itself and save you money certainly over 15 years and possibly within 7. A gas /oil boiler will never pay back, it will always continue to cost money, yet we never look for a payback on it..?
We never look at the cost of interest in providing gas and oil heating systems rarely look at the ongoing costs of the ownership of such systems.


Comments please !!

You asked for comments - where do I start!

Firstly I do not in any way accept that your figures are conservative; in fact they are highly optimistic.

Some general points:
When most(all) washing machines and dishwashers are cold fill, many of us use Domestic Hot Water(DHW) mainly for baths and (non-electric)showers.

So it largely doesn’t matter how big the house is, it is the number of people bathing/showering that determine the usage of DHW. So quoting a consumption of 25% for 3 bedroom detached house doesn’t mean a great deal unless you quote an occupancy.

So I fail to see how you jump to the conclusion that 25%(£195) of the £778 total bill for an average 3 bed detached house would be for DHW. In fact there are lots of studies that put the average household energy consumption for DHW at 4,000 – 5,000kWh p.a. That costed at 3p kWh for gas/economy 7 is more like £120-150 per year.

To save 50% overall of those costs(and I have never seen verified figures as high as 50% - let alone an incredible 70%) you are talking of a start point in savings of £60-£75 pa and not the £100 you claim. That is in line with the experience of people with solar systems fitted.

So even accepting that fuel prices are to increase(by your estimate) of 10% per year for the next 10 years you are looking at savings in the region of £1,000 over the next 10 years.

I don’t accept at all the standard ‘line’ of the solar industry that you will save £400 over 10 years on boiler servicing and replacements costs; but I can’t be bothered to argue – so will concede that point.

I note you have not included the cost of installing a thermal store, but quote £4,000 -£4,500 for a solar panel system.

A couple of points you have missed.
Cost of running a pump? Servicing costs?(Energy Saving Trust recommend it). Repairs to system (pump, piping, electronics, panels) After all if you factor in savings on repairs to boiler in your savings, why do you not factor in repairs in your costs?

One might also ask why guarantees are typically only 2 years if the systems are so reliable?

However all the above discussion on savings pales into insignificance when we consider 'real' money saving.

You claim that a saving of approx £2,400 over 10 years is possible. I maintain that a more realistic figure is less than half at an outside £1,200.

However to achieve those savings we are required to spend £4,000 to £4,500 to fit a solar panel system. If we take the mid-point and borrow the money at 6% you are paying £255 pa in interest even before you start paying off any of your capital.

So you pay out over 10 years £2,550 in order to save either £2,400 or £1,200(depending who one believes) and you still owe the £4,000 to £4,500.

You simply cannot ignore the borrowing costs(or compound loss of interest if you pay cash) of a system installed to save money. Your reasoning is akin to someone with a £100,000 mortgage saying my mortgage payments will be £4,000 a year for 25 years.

Any comments?