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ENVIRONMENT AND ENERGY
All the talk in the world doesn’t seem to make people ready to pay for energy efficiency.
her official residence in Waterkloof, Tshwane, as a pilot
project and case study, but it was found that its location
in the lee of a forested cliffside meant it was literally
impossible to convert. “That is more the exception than the
rule but shows why you need someone who knows what
he’s doing before embarking on a R20 000 installation.” that investment will undoubtedly save money, that kind of
horizon requires certainty one will be in one’s home for
that period of time (or that one can sell the home for a
price that includes the cost of the solar system), as well as
taking the risk that the unit lasts the full working life of
15 to 20 years.
What is likely to enforce an increase in uptake of solar
water heating systems is the continued increase in Eskom
tariffs, says Bredenkamp: “The forecast is for double-digit
increases in tariff for the next couple of years and I think
this may bring about a resurgence in interest in them in
the middle to higher income group.” One way to look at it is how much electricity one will be
able to buy over the next five years for the price of a solar
geyser, and how much that electricity saved will be worth.
This is done by working out the monthly repayment that
would be due for an option if it were fully financed over five
years at the current prime interest rate. Then calculate how
much electricity that monthly repayment amount would
buy over the next five years, using the current municipal
electricity rate in Johannesburg as it is due to escalate
over the coming years and a 3% inflation increase in price
for 2022 and 2023.
If it’s not an ethical decision, how does the financial
case work?
Many of the savings on alternative water heating systems,
whether solar or heat pumps, involve changes in behaviour,
which is not a financial matter. Even oft-touted timers on
geysers are shown to bring about savings only by changing
people’s behaviour rather than actual energy efficiency.
These calculations often rely on financial gymnastics
such as families changing their bath and shower times to
maximise solar heating of water, or are sometimes based
on cheaper systems with tanks too small to be effective.
Installing a solar water heating system remains a serious
investment. While a long enough investment horizon for
February 2020 Volume 25 I Number 12
In conclusion
The rule of thumb is that solar systems are assumed to
save around 50% on water heating costs, and real-world
testing in South Africa has corroborated that number.
At the moment, solar water heaters are ‘sold’ rather than
‘bought’ and a change in the financial case is what would
be needed to cause that resurgence more than all the talk
in the world about Climate Change. PA
www.plumbingafrica.co.za