1 kWh: what can be done with 1 kWh?

Understanding what 1 kWh (or 1 kWh) corresponds to helps to manage your electricity consumption and your electricity bill.
This page summarizes the definition, useful conversions, everyday examples, and tips for saving energy.

🔹 1 kWh, what is it? (definition & conversions)

The kilowatt-hour (kWh) is a unit of electrical energy.
1 kWh = 1,000 Wh (watt-hours).
1 kWh corresponds to the energy consumed by an electrical device of 1,000 watts (1 kW) operating for 1 hour.
Formula: Energy (kWh) = Power (W) × Time (h) / 1,000

Practical equivalences:

1 kWh = 1,000 W × 1 h
1 kWh = 100 W × 10 h
1 kWh = 10 W × 100 h

🔹 Concrete examples (indicative orders of magnitude)

📺 Living room

LED TV ~90–150 W → 1 kWh ≈ 6–11 h
Console + TV ~220–350 W → 1 kWh ≈ 3–5 h
Box/Modem ~8–12 W → 1 kWh ≈ 4–5 days (standby ≈ on)

🍳 Kitchen

Combined refrigerator: ~0.3–0.8 kWh/day → 1 kWh ≈ 1.5–3 days
Freezer ~200 L: ~0.5–1.2 kWh/day → 1 kWh ≈ 0.8–2 days
Microwave ~800–1,200 W → 1 kWh ≈ 50–75 min
Ceramic hob (1 burner) ~1,200–2,000 W → 1 kWh ≈ 30–50 min
Electric oven ~1,800–2,200 W → 1 kWh ≈ 27–33 min

🚿 Bathroom

Shower (DHW): ≈ 1.5–2.5 kWh depending on volume/temperature
Bath: ≈ 3–5 kWh

👕 Laundry

Washing machine (eco 30 °C): ≈ 0.5–1 kWh/cycle → 1 cycle with 1 kWh
Dryer: ≈ 2–3 kWh/cycle → 1/3–1/2 cycle with 1 kWh

💡 Lighting

LED bulb 10 W → 1 kWh ≈ 100 h
Halogen bulb 50 W → 1 kWh ≈ 20 h

🔥 Thermal comfort

Space heater 2,000 W → 1 kWh ≈ 30 min
Air conditioning small room 500–900 W → 1 kWh ≈ 1.1–2 h

💻 Office

Laptop 30–60 W → 1 kWh ≈ 16–33 h
Desktop PC 120–500 W → 1 kWh ≈ 2–8 h

🚗 Electric car

Typical consumption: 12–20 kWh / 100 km
With 1 kWh → ≈ 5–8 km (depending on model, speed, weather)

🔹 How much does 1 kWh cost? (price & calculations)

The cost depends on your electricity contract (peak/off-peak hours, taxes).
Formula: Cost of usage (€) = Energy (kWh) × price per kWh (€).

Example:

Device 150 W used for 3 h → (150 × 3) / 1,000 = 0.45 kWh
If price per kWh = €0.25 → cost ≈ €0.11

👉 Hourly cost of a device: (Power W / 1,000) × price per kWh

🔹 Tips for saving energy

Lighting: switch to LEDs, adjust the number of light points
Standby: turn off with switchable power strips
Cooking: use lids, convection heat, microwave for reheating
Washing: eco programs at 30 °C, prefer air drying
Cooling: 4 °C for the fridge, −18 °C for the freezer, defrost regularly
Heating / AC: aim for 19–20 °C in winter, improve insulation and sealing
Monitoring: check the electricity bill or supplier's app; measure a device with a plug wattmeter

⚡ Calculateur de consommation en kWh

Saisis la puissance de l’appareil (W), la durée d’utilisation (heures) et, si tu le souhaites, le prix du kWh (€) pour estimer la consommation électrique et le coût réel.

Rappels : Énergie (kWh) = Puissance (W) × Temps (h) / 1 000. | Durée avec 1 kWh (h) = 1 000 / Puissance (W).

Frequently Asked Questions

What is a kilowatt-hour (kWh)?

The kilowatt-hour (kWh) is a unit of electrical energy. 1 kWh = 1,000 Wh. It is the energy consumed by a 1,000 W (1 kW) device operating for 1 hour. Formula: Energy (kWh) = Power (W) × Time (h) / 1,000.

What can you do with 1 kWh in the living room?

In terms of magnitude: LED TV ~90–150 W → 6 to 11 h; Console + TV ~220–350 W → 3 to 5 h; Internet box ~8–12 W → about 4 to 5 days (standby close to on).

How long can you cook with 1 kWh?

Microwave ~800–1,200 W → 50 to 75 min; Ceramic hob (1 burner) ~1,200–2,000 W → 30 to 50 min; Electric oven ~1,800–2,200 W → 27 to 33 min. Cold: combined refrigerator ~0.3–0.8 kWh/day → 1.5 to 3 days; freezer ~0.5–1.2 kWh/day → 0.8 to 2 days.

What hot water consumption with 1 kWh?

Domestic hot water is energy-intensive: a shower typically represents ~1.5 to 2.5 kWh (depending on volume and temperature) and a bath ~3 to 5 kWh. With 1 kWh, only a fraction of these needs is covered.

Can you run a washing machine cycle with 1 kWh?

Yes: an eco 30 °C program consumes about 0.5 to 1 kWh per cycle. However, a dryer consumes ~2 to 3 kWh per cycle, so 1 kWh covers only about 1/3 to 1/2 of a cycle.

How long can you light with 1 kWh?

With a 10 W LED, 1 kWh allows about 100 h of lighting. Conversely, a 50 W halogen will only operate for about 20 h with 1 kWh.

How long can you heat or air-condition with 1 kWh?

Auxiliary heating 2,000 W → ~30 min with 1 kWh. Air conditioning a small room ~500–900 W → ~1.1 to 2 h with 1 kWh (insulation remains the primary lever for savings).

What is the consumption of a computer with 1 kWh?

Laptop 30–60 W → ~16 to 33 h with 1 kWh. Desktop PC 120–500 W → ~2 to 8 h. A box/modem ~8–12 W → ~4 to 5 days.

Can you drive an electric car with 1 kWh?

Yes. In terms of magnitude, consumption is often between 12 and 20 kWh/100 km, or about 5 to 8 km traveled with 1 kWh depending on the model and conditions.

How much does 1 kWh cost and how to estimate it for use?

Cost (€) = Energy (kWh) × price per kWh. Example: device 150 W used for 3 h → (150 × 3) / 1,000 = 0.45 kWh. If the price per kWh is €0.25, the cost ≈ €0.11.