On the 8th July, Carte Blanche Conusmer aired an episode detailing the difference in Payback periods between a Solar Water heating system and a Heat Pump.
Below is the dialogue from this episode.
This show was not meant to favour one system over another, it was aired to help you decide what system will work best for you and to give you the reassurance that Solar Water Heating Systems and Heat pump technologies are technologies that you must start adopting, if you havnt yet done so.
For more information on our Solar Water Heating systems and Heat Pump technology, please visit the relevant product pages.

For any queries related to our products, kindly contact us at marketing@its-solar.com

Dialogue from Carte Blanche Consumer - with thanks to Carte Blanche

For the next 3 years Eskom has warned us that our bills will go up by around 25% annually. Heating your household water contributes to about 40% of these costs and South Africans are scrambling for solutions.

Bongani Bingwa (Carte Blanche presenter): ‘Many of us believe that if we just switch off geyser in the morning and then on again in the afternoon we will save electricity. Well, not quite. Studies have shown it takes as much energy to heat up cold water in your geyser as if you had left it running the whole day. So, yes, you might save the national grid power, but your bill is likely to stay more or less the same.’

So those consumers that can afford it are turning to solar systems.

Solar Expert: ‘Typically you will get about 80% saving of that electricity that your electric geyser is going to use from your solar water heater.’

He warns that our average spend on heating water is about to go up dramatically.

Solar Expert: ‘In a lot of households that is about R300 per month, but that is going to escalate to way over R500 per month in a few years. And it will eventually get to nearly R1000 per month that homeowners are going to spend just on heating hot water.’

Bongani: ‘But an alternative that most consumers have hardly heard about is a heat pump. Its biggest selling point is that it costs you much less upfront.’

Dr Martin van Eldik is a part-time professor at North-West University. He also has an interest in a commercial heat pump operation and is a co-author in a study in which the economic viability of heat pumps to a low and medium quality solar system is researched.

Bongani: ‘And which one came out best?’

Dr Martin van Eldik (School of Mechanical Engineering: North-West University): ‘The heat pump came out the best, if you look at the household that typically uses 200 litres of hot water per day. With the heat pump you have a payback period of less than two years. With the solar panel you get a payback of in the region of about four years and with the cheap solar panel in the region of about six years.’

Which is why when Dr Emile Kotze looked at ways to save electricity for his household of six he chose a heat pump.

Dr Emile Kotze (Homeowner): ‘I looked at gas and I’ve looked at sun energy and I’ve looked at heat pumps and heat pumps were the most cost effective for me.’

Bongani: ‘Have you seen a saving?’
Dr Kotze: ‘I have seen a huge difference ja. Before the price increase I saw about R400 to R500 per month.’

Bongani: ‘And with the price increase?’

Dr Kotze: ‘More than R500… say near to R600, yes.’

Martin explains that heat pumps work on the same principle as air conditioners. They draw their energy from the outside or ambient air, which is why the units are installed outside.

Dr Van Eldik: ‘And we take that energy, we push it into our heat pump cycle -the vapour compression cycle. We pump it up to a higher temperature and pressure point and then there we push all of that energy that we have extracted into the water. And we can heat all of that water up to 55 or 60 degrees.’

For example - say your geyser needs three units of electricity to create three units of heat. A heat pump will use one unit of electricity and two units of heat from the ambient air to generate the same amount of heat, so saving around 67%.

Bongani: ‘What about the quality of the hot water - have you seen any difference?’

Dr Kotze: ‘I think the temperature is at 55 degrees, but that’s all. It’s a little bit less than my geyser. My geyser is 60 degrees, was 60 degrees, but no difference at all.’

Martin argues that while solar may promise around a 70% saving on your water heating bill, low quality panels don’t heat the water enough forcing homeowners to use backup electricity at night and when it’s overcast.

Dr Van Eldik: ‘What happened with those panels is that studies have shown that you only save about 18% instead of 70% on your electricity bill.’

Prices for solar systems vary, but on average small systems start at around R12 000, the middle of the range from about R16 000, and at the high end you will pay about R26 000. That includes the rebate, which you can only claim from Eskom after purchasing. Currently no rebate is offered on heat pumps.

Dr Van Eldik: ‘The rebate on heat pumps is not in place yet. It looks like it should be in place in the next two months. Now the rebate that we are talking about is in the region of R5000 per unit. So, if your installation is about R12500, you only pay about R7500 for your heat pump installation.’

We asked Eskom to clarify when and if the heat pump rebate will come into effect, but they did not respond timeously.

Bongani: ‘Why should I go for solar heating versus for instance a heat pump?’

Solar Expert: ‘Heat pumps is a very good alternative technology.’

Bongani: ‘Because it’s cheaper upfront and the payback period is half of what a solar heater would be?’

Solar Expert: ‘Well, whether it’s half or two thirds we recognise that. Sure, the initial price might be lower and the initial payback period might be lower, but your running costs in terms of kilowatt hours required to run a heat pump is always going to be higher than the running costs of a solar water heater. So, if you look at a five or seven year period you most probably get a cross over where solar water heater now becomes more viable.

The payback period for solar may have started off at an average of six years, but with the new higher electricity tariff increases that has already dropped to three, four years.

Bongani: ‘The deal breaker for solar heating system manufacturers is that whatever point you finish paying it off, you essentially have free hot water. And, of course, it’s green.’

Solar Expert: ‘Installing a solar heater or a solar geyser is equivalent to taking a small car off the road.’

Martin’s study shows that both the heat pump and the solar water heater provide significant savings over a conventional geyser.

But what it boils down to, it seems, is a choice between short term savings on a heat pump with its shorter payback period and long term savings on a good solar system.