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If you want to save money on your electricity bill, an alternative energy source for water heating is a great investment.

A geyser is one of the most energy-intensive items in a household, using roughly 30% to 40% of household electricity. Replacing the water heating system with one that uses an alternative source of energy is more efficient and will save money.

Understanding the difference between a solar water heater and a heat pump (and which is most suitable for your requirements) is a critical first step.

Solar Water Heater Heat Pump
A SWH uses the radiation from the sun to generate heat. The size of the solar panel will determine how much energy can be collected from the sun. The heat pump uses a relatively small amount of electricity to extract a lot of energy from the surrounding air. A heat pump is also using the energy from the sun but only indirectly and so it can work day and night, winter and summer.
It can be connected to an electric element to further heat the water during winter and overcast days.  It works at night and on overcast days as it relies on air temperature and not direct sunlight.   
A high-efficiency, properly sized SWH system will typically provide up to a 50% saving on the energy required for hot water.*  A high efficiency heat pump produces 4 times more thermal energy as what it uses electrically – in other words a 75% saving on the water heating bill.*
Variances in the facing and incline of the solar collector panels will influence the output of the system. The correct placement of a heat pump is essential to ensure sufficient savings. It needs to face north, east or west.
Life expectancy of the system is 10 years or more. Life expectancy of the system is 10 years or more.
Payback period is between 3-5 years. * Payback period is between 1-3 years. *
Routine maintenance may be required on the valves, but not on the system itself. Requires more maintenance due to the compressor and moving parts.

*Please note: As every household is different, the savings and pay-back period will vary. This will depend on the model, size and the positioning of the system as well as how much hot water the home uses.

If you have any questions about water heating options, the City of Cape Town has a list of accredited service providers who are experienced in installing solar water systems.

 

How much can I expect to save when installing a Solar Water Heater?

The savings and payback period will vary for each household. This depends on the model, size and the positioning of the system as well as how much hot water the home uses. The general guideline is that a solar water heater can save up to 50% or more of your hot water bill.

The following table provides some indication of what savings is typical for various households, and what repayment costs you can expect if you add the installation of a solar water heater to your existing bond facility.

Family Size

5 minute Showers/day

Baths/day

Recommended SWH size

Typical SWH System Cost

Typical monthly saving (avg)*

Typical monthly repayment on bond (10 yrs at 10.5% interest)

Typical simple payback period (yrs) if paid cash

1

1

0

150

R 19 165

R 116.60

R 265.53

8.84

1

0

1

150

R 19 165

R 159.00

R 265.53

6.68

2

2

0

150

R 19 165

R 232.51

R 265.53

4.75

2

0

2

150

R 19 165

R 288.05

R 265.53

4.00

2

1

1

150

R 19 165

R 263.40

R 265.53

4.25

3

3

0

150

R 19 165

R 306.53

R 265.53

3.75

3

2

1

200

R 21 165

R 369.87

R 293.24

3.50

3

1

2

200

R 21 165

R 394.52

R 293.24

3.34

3

0

3

200

R 21 165

R 419.17

R 293.24

3.17

4

4

0

200

R 21 165

R 413.01

R 293.24

3.17

4

3

1

200

R 21 165

R 437.66

R 293.24

3.00

4

2

2

300

R 30 450

R 501.00

R 421.88

3.67

4

1

3

300

R 30 450

R 525.65

R 421.88

3.50

4

0

4

300

R 30 450

R 550.29

R 421.88

3.42

5

5

0

300

R 30 450

R 519.48

R 421.88

3.59

5

4

1

300

R 30 450

R 544.13

R 421.88

3.42

5

3

2

300

R 30 450

R 568.78

R 421.88

3.34

5

2

3

300

R 30 450

R 593.43

R 421.88

3.17

5

1

4

300

R 30 450

R 617.15

R 421.88

3.08

5

0

5

300

R 30 450

R 637.20

R 421.88

3.00

* Based on purchasing the system with cash (no financing costs), using the City of Cape Town’s 2016/17 electricity tariff

The green row above is an indication for an average household of four people. 

Please Note: These calculations come with assumptions around shower flow rate and time, and average bath capacities, and are dependent on typical heat absorption capacities of solar water heater. They should be taken as indicative, not absolute, and will vary from household to household.