Put quality first with solar panels

The most common question about eco systems is payback: "How long will it take to recoup my investment?"

25 February 2010

Just over 10 years ago I bought some new shoes - they cost £99 in the sales.

About two months ago I bought some shoes for €19 and got one pair free.
The 10-year-old ones are still nearly as good as new, one pair of the new ones is ruined.

I can see now that the £99 ones were worth the outlay - and the same applies to installing environmentally-friendly systems in the home.

The commonest question about eco systems is payback: “How long will it take to recoup my investment?”

This is one of those “How long is a piece of string?” questions - there are so many variables to examine.

Let us consider one specific product, the one considered to be the best investment: a solar hot water system.
So, what is the payback?

Well, for a start, solar power does actually have one. If you buy oil, gas or electricity there is no payback ever. No matter how much gas, oil or electricity you buy and no matter how long you buy it for, you never get your money back.

You will also have to service, maintain and ultimately replace your boiler at some time.

Payback is usually calculated as the equipment’s capital cost divided by the annual fuel bill savings.

Unfortunately this is inaccurate and misleading.

You need to take a wider view and factor in future energy increases, inflation, the savings in boiler or equipment servicing and the lifetime of such equipment.

There are also other factors beyond our control that will affect this calculation such as the new carbon tax which will put up the cost of oil and gas if it is introduced in July.

Using solar power to complement central heating systems is likely to become much more popular purely because of this new carbon tax - and who knows what other taxes or environmental penalties will be introduced?

If all of the variables are taken into account it is generally accepted that a good solar thermal system offers a payback of between five to ten years.

Remember too there are government incentives for green installations like this, such as tax credits and reduced TVA (VAT) rates, all of which can reduce these payback times still further.

Up front finances aside, such installations are good for the environment, increase the value of your home, and make us all less susceptible to ever-increasing energy costs.

Whatever form of green energy system you might consider it is vital you choose one that will perform efficiently for a very long time with a rock-solid guarantee.

A payback period of 10 years is not much use if your system only lasts 10 years (or less) and I have seen some systems (and shoes) that have neither performed nor lasted as long as they should have.

It is possible to obtain efficiency figures for solar power systems - they are recorded by the test laboratories that evaluate them.

The best-known are the Solar Keymark tests.

Products which get the Solar Keymark label are certified to have reliable quality and reliable performance information.

One of the key tests for solar power systems is optical efficiency, which measures how much light is captured and converted into useful energy.

For example, here are the key figures from two mainstream suppliers of solar systems in France: The optical efficiency of system A is 0.37 while the optical efficiency of system B is 0.85.

System B is therefore more than twice as efficient as the other, so choose wisely.

The upfront costs are a one off, operating costs are for life.

You always get what you pay for, so maybe the £99 shoes were the better buy after all.

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