As the cost of utilities continues to increase and load shedding remains a constant issue, you may have several questions concerning your geyser/water heater. You may be curious about how much electricity it consumes daily, ways to reduce your electricity usage, or how long it takes to heat up once power is restored. Given these concerns, we’ve compiled a list of frequently asked questions to provide you with helpful information and insights about geysers.

10 General Geyser Questions

1. What is a geyser?

A geyser refers to a household water heater or boiler that heats and stores water for use in your home. It heats the water using electricity, gas or solar power and stores it in a tank until you need it. When the hot water tap is turned on, the water travels from the tank through your plumbing to various outlets such as taps, showers, or bathtubs.


2. How do geysers work?

Your home’s water heater pumps cold water through an inlet pipe into a reservoir tank containing an element. The element heats the cold water gradually to the temperature indicated on the thermostat. As the water warms up, it rises to the top and leaves through the outlet pipe, which runs to whichever hot water tap is in use. Once the water has reached the indicated temperature, the element turns off.

3. How does a gas geyser work?

A gas geyser works by heating the water using a gas burner inside the unit. When you open the hot tap, old water enters through an inlet pipe and passes over a heat exchanger, where it is heated by the gas burner. Once you close the hot tap, the gas burner turns off, and the gas geyser remains off until you turn on the hot tap again.

4. How does a solar geyser work?

Solar geysers heat up water using the sun’s energy through a process known as convection. The water in the solar panels is heated and rises into the water tank above. The hot water then flows into the tank inside your home, but bear in mind that if the water heater were installed in your ceiling, you would need a circulating pump to help pump the water from the tank to the solar panels on your roof. This ensures that the water is continuously heated and circulated, providing a steady hot water supply for your home without relying as much on traditional energy sources.

It is important to note that the water won’t be as hot on cloudy days as it would be on a very sunny day. On cold, cloudy days, you will still need to use electricity to heat your water.

5. Solar Geyser Cape Town: How much is a solar geyser?

The price of installing a solar water heater can vary significantly based on the system your home needs and which one you choose in the end. On average, solar geyser prices range between R12 000 – R25 0000, excluding labour and installation. Low-pressure systems are slightly cheaper but don’t perform as well.

Besides the initial cost for installation, a solar panel geyser can help save up to 60% on your electricity bill. Electric geysers cycle on and off anywhere from 15 to 30 times per day using considerable amounts of electricity. Of course, the savings will be marginally less during winter if you need to use electricity frequently to heat water.

6. How to install a geyser

It is crucial to understand that installing a geyser can be hazardous if not done properly. Geyser installation is a complex task that demands a high level of proficiency, expertise, and knowledge. Faulty installations can lead to expensive repairs and pose significant safety risks. Even if you feel confident in your ability to handle water heater repairs on your own, it is recommended to have a professional plumber examine your water heater once it’s installed. 

Here is a brief guide on how to install an electric geyser:

Step 1: Choose the right location

Determine where you want to install your water heater. It should be installed in an area that has enough space for the unit and is close to the water and electrical connections.

Step 2: Purchase the correct water heater

Make sure to purchase a water heater that is the appropriate size for your household’s needs. You should also ensure that it complies with the applicable legislation, which can be found here: Plumbing Compliance SANS 10254: Installation, Replacement and Repair of Hot Water Systems.

Step 3: Prepare the installation area

The area where you’ll install the geyser should be cleared and prepped. Remove any debris or obstacles around the installation area.

Step 4: Install the plumbing

Connect the water heater to the water supply and ensure it’s properly attached to prevent leaks.

Step 5: Install the electrical connections

Connect the water heater to the electrical supply and ensure the wiring is done correctly. Always follow the manufacturer’s instructions on how to connect the electrical supply.

Step 6: Turn on the geyser

Once everything is properly connected and installed, turn on the water heater and let it heat up. Check for any leaks or issues and address them immediately.

Step 7: Maintenance

After installation, it’s essential to maintain your water heater regularly to keep it functioning optimally. This includes checking and replacing the thermostat and safety valves, as well as flushing the tank to remove any sediment buildup on a regular basis.

7. How to install a gas geyser

Installing a gas geyser can be dangerous if not done correctly, which is why it’s recommended to hire a licensed plumber to install it. A professional has the knowledge and experience to ensure that the gas geyser is installed safely, in compliance with local regulations, and in accordance with the manufacturer’s instructions. 

It’s also important to note that if you install the gas geyser yourself and something goes wrong, you may void the manufacturer’s warranty, and your insurance may not cover any damages or injuries that may occur during the installation process.

8. What size gas geyser do I need?

When determining the size of the gas geyser, it’s important to consider the number of people in the household, their hot water usage habits, and whether they use hot water simultaneously. If there are multiple people using hot water at the same time, it may be wise to get a water heater that is one size up from the one you think your home needs.

As a general guide, the following table provides an estimate of the required geyser size based on the amount of hot water used per appliance:

  • One tap/washing machine: 6-12L
  • One shower: 16L
  • One shower and a single tap: 20L
  • Two showers: 26L
  • Three-four showers: 32L

It’s important to note that these figures are an estimate and should be used as a guide only. Other factors, such as incoming water temperature, the frequency of hot water usage, and peak demand periods, should also be considered. It’s best to consult a licensed professional who can assess your hot water needs and recommend the appropriate size gas geyser for your household.

9. How to test a geyser thermostat

To test a water heater thermostat, you can follow these steps:

  1. Turn off the power supply to the water heater.
  2. Remove the access panel to the thermostat.
  3. Use a multimeter to check the resistance between the two terminals on the thermostat. The resistance should be in the range specified by the manufacturer.
  4. If the resistance is outside the specified range, replace the thermostat.
  5. If the resistance is within the specified range, turn the power supply back on and allow the geyser to heat up.
  6. Check the temperature of the water coming out of the tap and compare it to the thermostat’s temperature setting.
  7. If the temperature is not consistent with the thermostat setting, adjust the thermostat accordingly or replace it if necessary.

It’s important to note that testing a geyser thermostat can be dangerous and should only be done by a licensed professional who has the necessary training and experience to handle electrical components safely.

10. How to fix a leaking geyser

A leaking geyser can cause significant damage to your home and should be addressed as soon as possible. Signs that your water heater may be leaking include water pooling around the base, a drop in hot water pressure, or a hissing sound coming from your water heater.

If you suspect your geyser is leaking, the first step is to turn off the water and electricity/gas supply to the water heater. Next, drain the tank to prevent further leaking and inspect it for any visible signs of damage or corrosion. Check the pressure relief valve for leaks or damage, as this is a common source of geyser leaks. If the leak is coming from the pressure relief valve, it may need to be replaced.

If the leak is coming from the water heater itself, it may need to be repaired or replaced. Sometimes, the leak may be coming from a pipe or connection, so check for any loose or damaged connections and tighten or replace them as needed. Once the issue has been identified and resolved, turn the water and electricity/gas supply back on. 

Need more information? We recommend you read the following blog: Bathroom Renovations: Where To Start.

6 Geyser Heating & Electricity Consumption Questions

1. How long does a geyser take to heat up?

To determine how long it will take for your small geyser to heat up, there are several factors to consider. Firstly, the water temperature in the tank plays a significant role, especially in the winter months when groundwater can be significantly colder. Additionally, the thermostat setting, condition of the water heater, and level of insulation can all impact the heating time. 

The most accurate way to determine how long your geyser takes to heat up is to turn it off and wait until the hot water has run out. From there, turn it on and check the water temperature every hour until you reach your desired temperature. While this method can be time-consuming, it is the only foolproof way to test how long your water heater takes to heat up.

2. How long does a 150l geyser take to heat up?

It takes nearly 3 hours for a 150lt geyser to heat up from 15°C to 65°C.

3. How long does a 200l geyser take to heat up?

Assuming your water heater takes 1 hour to heat 50l of water from 15-65°C, a further 50 litres could take another hour, so approximately 4 hours. As mentioned above, this will depend on your unique situation.

4. How much electricity does a geyser use?

Are you wondering how much electricity does a water heater use per day? The answer really depends on several factors, including:

  • The type, size and condition of your water heater
  • The amount of hot water your household uses
  • How frequently do you use hot water throughout the day
  • Whether your water heater is insulated or not

On average, a 4-person household with a 200l geyser will use approximately 14kWh of electricity daily if it is constantly left on.

5. How many watts does a geyser use?

As mentioned above, heating a 150-litre geyser from completely cold water (15 degrees Celsius) to 65 degrees Celsius can take close to three hours. This requires the usage of 8.72kW (8720 watts) of electricity with a 3kW element. Remember, it’s not often that the water in your water heater will be completely cold, so it won’t have to work as hard to heat the water. This estimation does not consider your specific circumstances, such as the size of the water heater tank, which heating element is being used, and the temperature of the water.

6. Does switching off the geyser save electricity?

Switching off a water heater can save electricity, but the amount saved depends on how long it is switched off and whether hot water is drawn off during that time. For example, if a 150lt water heater is turned off for 12 hours after reaching a temperature of 65 degrees C, it can save approximately 0.87kW, resulting in a daily saving of R1.43. This practice can help load shift during peak electricity demand times, but it has little financial benefit in the long run. 

The best way to save money is to reduce hot water consumption, install a geyser timer and lower the temperature setting of the thermostat. It is recommended to keep the temperature between 50-55 degrees Celcius during summer and 60-65 degrees Celcius in winter for the best results.

Geyser Timers: What Are They & Can They Save Electricity?

1. What is a geyser timer?

A water heater timer is an electronic device that is used to control the operation of an electric geyser. It is designed to help you save energy and reduce your electricity bill by regulating when your water heater turns on and off.

2. Does a geyser timer save electricity?

By taking control over how many times your water heater heats up its water, a geyser timer can significantly reduce your expenses. Setting it to heat water once a day for two hours can cut more than 60% off the bill. For bigger families, setting it twice a day for two hours can save about 37% on your electricity bill. Knowing when you’ll need hot water and sticking to your routine is critical to saving money with a timer.

3. How to set a geyser timer?

To set a geyser timer, first, locate the geyser timer switch, which is usually near the water heater or in the distribution board. Next, determine the time of day when you want the water heater to switch on and off. For example, if you want your water heater to switch on at 5 am and switch off at 7 am, set the timer to turn on at 5 am and turn off at 7 am. Make sure to adjust the timer according to the manufacturer’s instructions and ensure that it is connected to the water heater properly. Once the timer is set up, the water heater will only heat water during the designated times, which can help save money on electricity.

For more in-depth instructions, you can watch a video from Builder’s Warehouse here: How To Set and Use Geyser Timers.

Water Heater Installations, Repairs and Maintenance with Absolute Plumbing

At Absolute Plumbing, we specialise in water heater installation, repair and maintenance for both commercial and residential properties. Our experienced plumbers can evaluate your current system and assist you with selecting the right type of heating system that meets your specific needs. We also provide regular maintenance services to keep your water heater running efficiently and safely. 

For more information on geyser solutions and other plumbing services, contact us via our website or call 084 872 2758.  

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