1. How does a water heater work?

An electric water heater heats a supply of water and stores it in an insulated tank. When you open a shower, hot water from the water heater is mixed with cold water to reach a comfortable temperature.

Most water heaters heat water to approximately:

• 60°C to 65°C

During showering, this hot water is mixed with cold water to achieve a shower temperature of approximately:

• 38°C to 40°C

This allows you to shower longer than just the capacity of the water heater.

2. How much shower water does a 100 liter water heater provide?

Because hot water is mixed with cold water, a 100 liter water heater typically provides more usable shower water.

On average, you can count on:

• 100 liter water heater → ±160 liters of shower water

This is because hot water is diluted with cold water.

3. How much water do you use while showering?

The amount of water you use primarily depends on the shower head.

Average shower head water consumption

• Water-saving shower head → 6 liters per minute
• Average shower head → 8 liters per minute
• Rain shower → 12 to 15 liters per minute

4. How long can you shower with a 100 liter water heater?

With approximately 160 liters of usable shower water, you can expect the following:

• Water-saving shower → ±25 minutes
• Normal shower → ±20 minutes
• Rain shower → ±10-13 minutes

These are average values; in practice, this may vary slightly.

5. How many people can shower with a 100 liter water heater?

Many households wonder if a 100 liter water heater is sufficient for multiple people. This mainly depends on the duration of showering and the type of shower head.

Average scenarios

• 1 person → ±20 minutes of showering
• 2 people → ±10 minutes per person
• 3 people → ±6–7 minutes per person
• 4 people → usually not enough hot water without reheating in between

In a multi-person household, it may be necessary for the water heater to reheat in between uses.

6. How long does it take for a 100 liter water heater to reheat?

When the hot water in the water heater runs out, the water must be reheated. The reheating time depends on the power of the water heater.

Average reheating time

• 1500 watt water heater → ±4 hours
• 2000 watt water heater → ±3 hours
• 3000 watt water heater → ±2 hours

Many modern water heaters continuously reheat while you use water, which sometimes allows you to shower a bit longer.

7. How much energy does a 100 liter water heater consume?

A 100 liter electric water heater uses electricity to heat water. Energy consumption depends on:

• How often you shower
• How hot the water is set
• How well the water heater is insulated

Average energy consumption

• 1 person → ±800 kWh per year
• 2 people → ±1200 kWh per year
• 3 people → ±1600 kWh per year

At an electricity price of €0.35 per kWh, this means:

• ±€23 per month for 1 person
• ±€35 per month for 2 people
• ±€46 per month for 3 people

8. 100 liter water heater vs heat pump water heater

More and more households are now opting for a heat pump water heater. This type of water heater uses a heat pump to heat water and therefore consumes much less electricity.

Energy consumption comparison

• Electric water heater → ±1200 kWh per year
• Heat pump water heater → ±350–500 kWh per year

A heat pump water heater can therefore use up to 60–70% less energy.

9. When is a 100 liter water heater sufficient?

A 100 liter water heater is usually suitable for:

• 1 to 2 people
• Small apartments
• Student housing
• Kitchens and small bathrooms

For families with multiple people, a larger water heater is often recommended.

10. Tips to shower longer with a 100 liter water heater

There are several ways to increase the available amount of hot water.

• Use a water-saving shower head
• Set the water heater to a higher temperature
• Shower a little shorter
• Allow the water heater to reheat in between showers
• Choose a larger water heater when multiple people shower consecutively

11. Frequently asked questions about a 100 liter water heater

1. How long can you shower with a 100 liter water heater?

On average between 15 and 25 minutes depending on the shower head and water temperature.

2. Is a 100 liter water heater enough for 2 people?

Yes, usually, if both people shower for about 10 minutes.

3. Is 100 liters enough for a family?

For families, a 150 or 200 liter water heater is usually recommended.

4. How long does it take for a water heater to reheat?

This usually takes 2 to 4 hours depending on the power.

5. Can a water heater run out during showering?

Yes, when the entire supply of hot water has been used.

6. Does a water heater use a lot of electricity?

Electric water heaters use more electricity than heat pump water heaters.

7. What is the best water heater for a family?

For families, a 150 to 200 liter water heater is often used.

12. Conclusion: how long can you shower with a 100 liter water heater?

With a 100 liter water heater, you can typically:

• Shower for 20 to 25 minutes with a water-saving shower
• Shower for 15 to 20 minutes with a normal shower
• Shower for 10 to 12 minutes with a rain shower

For households with 1 or 2 people, a 100 liter water heater is usually sufficient. Larger households often choose a larger water heater.