How many kW do you need to heat your space? Here's how to calculate it easily

When choosing a Zibro laser heater or Wick heater, one of the most important questions is: how many kW of power do I need? Too little power means your space will not get warm enough. Too much means unnecessary costs and inefficiency.

In this article, we explain step by step how to calculate this easily. No guesswork, but a practical method you can apply immediately.

What does kW mean for a kerosene heater?

The power of a heater is expressed in kilowatts (kW). This indicates how much heat the heater can deliver per hour. Simply put: the higher the kW, the larger the space you can heat.

At Zibro, you will find laser heaters and Wick heaters with different power ratings, so you can always choose the right model for your situation.

Step-by-step method for calculating kW

The basic formula we use is:

Required power (kW) = (room volume in m³) × (W/m³ factor)

Where:

• Room volume = length × width × height (in meters)
• W/m³ factor = heat requirement per cubic meter

The W/m³ factor depends on:

• Insulation of the space
• Outdoor temperature
• How “airtight” the space is

Useful guideline for the W/m³ factor

• Poorly insulated / unheated: 70–90 W/m³
• Average insulation: 50–70 W/m³
• Well insulated: 30–50 W/m³

Want to keep it simple?

Use 60 W/m³ as a guideline for a standard space.

Example calculation

Suppose you have a workshop measuring 8 m × 6 m × 2.5 m = 120 m³.

We use 60 W/m³ (standard):

120 m³ × 25 W/m³ = 3000 W = 3.0 kW

In this example, you therefore need approximately 3.0 kW of power to get the space comfortably warm.

How do you choose the right Zibro heater?

Now that we know you need approximately 7.2 kW, look in the right category:

• Laser heaters with 6–8 kW – ideal for living spaces and well-insulated rooms
• Laser heaters with 8+ kW – for larger spaces or spaces that are difficult to keep warm
• Wick heaters around 7 kW – a good solution without electricity, e.g. for a garage or workshop

Is your required power just between two sizes? In general, choose the slightly larger model for greater comfort and faster heating.

Practical tips for a more accurate result

• Also check the FAQ for ventilation and safety tips.
• Take into account:
• Insulation quality
• Height of the space
• How often you use the heater
• When in doubt, a little extra kW can be more comfortable than too little.

Frequently asked questions about power

Can I also use a laser heater in poorly insulated spaces?

Yes — but calculate using a higher W/m³ factor (70–90 W/m³) to prevent insufficient capacity.

How many kW is normal for a garage?

For an average garage (±15–30 m²), 5–8 kW is usually sufficient, depending on insulation and the desired temperature.

Can a Wick heater provide enough power?

Certainly — Wick heaters around 6–8 kW are perfectly suitable for workshops and sheds, especially if you do not have electricity.

Conclusion

You choose the right kW by calculating volume × heat requirement. With our step-by-step method, you know exactly what you need, without guesswork.

Use this to search specifically among the laser heaters and Wick heaters on ZibroOnline. This way, you avoid disappointment and ensure efficient, comfortable heating.