Choosing the right light bulb might seem straightforward, but with so many options on the shelf at your local hardware store, it can get confusing fast. Understanding the differences between LED, halogen, and incandescent bulbs will help you make smarter choices for your home — reducing your power bill and the number of times you're up a ladder swapping globes.
How Each Bulb Type Works
Incandescent bulbs are the traditional technology most of us grew up with. They work by passing electricity through a thin tungsten filament, which heats up and glows. They're simple and cheap to buy, but extremely inefficient — the vast majority of the energy they use is lost as heat rather than light.
Halogen bulbs are essentially an improved version of incandescent technology. They use a tungsten filament inside a small quartz envelope filled with halogen gas, which allows the filament to burn hotter and brighter. They're more efficient than old-school incandescents and produce a crisp, white light, but they still run very hot and use considerably more power than LEDs.
LED (Light Emitting Diode) bulbs work on an entirely different principle — they pass electricity through a semiconductor, which emits light directly. This process generates very little heat, making LEDs far more energy-efficient than either of the other two technologies.
Comparing the Key Differences
Here's a quick side-by-side comparison to help you see the differences at a glance:
| Feature | Incandescent | Halogen | LED |
|---|---|---|---|
| Energy efficiency | Very low | Low–moderate | Very high |
| Typical lifespan | ~1,000 hours | ~2,000–4,000 hours | ~15,000–25,000 hours |
| Heat output | Very high | High | Low |
| Upfront cost | Low | Low–moderate | Moderate (falling fast) |
| Running cost | High | Moderate | Low |
| Dimmable | Yes | Yes | Many (check label) |
| Instant full brightness | Yes | Yes | Yes (most modern LEDs) |
| Available in NZ | Being phased out | Yes | Widely available |
Note: Lifespan and cost figures are approximate guides and vary by brand and product.
Energy Use and Your Power Bill
This is where LEDs really shine (pun intended). A typical LED bulb uses a fraction of the wattage of an incandescent bulb to produce the same amount of light (measured in lumens). For example, an LED drawing around 8–10 watts can produce the same brightness as a 60-watt incandescent. Multiply that saving across every light fitting in your home and it adds up quickly.
Energywise — the New Zealand government's energy efficiency resource — recommends switching to LEDs as one of the simplest ways to reduce household energy consumption. With New Zealand electricity prices being a real concern for many households, this is a practical step worth taking.
Lifespan and Replacement Costs
While LEDs cost more upfront than halogens or incandescents, their dramatically longer lifespan means you'll buy far fewer bulbs over time. An LED can last many times longer than a halogen equivalent, meaning less waste and fewer replacement purchases. When you factor in both the purchase price and the running cost over several years, LEDs are almost always the most economical choice.
Light Quality and Colour Temperature
All three bulb types can produce good quality light, but they differ in character:
- Incandescent bulbs produce a warm, yellowish light that many people find cosy and flattering.
- Halogen bulbs produce a bright, crisp white light — popular in kitchens, bathrooms and task lighting.
- LED bulbs are available across a wide range of colour temperatures, from warm white (similar to incandescent) through to cool daylight tones. Look for the Kelvin (K) rating on the packaging — around 2,700K is warm white, while 5,000K+ is daylight.
For living areas and bedrooms, most NZ homeowners prefer warm white LEDs. For kitchens, bathrooms and workspaces, a neutral or cool white works well.
Dimming and Compatibility
If you have dimmer switches, take care — not all LED bulbs are dimmable. Always check the packaging before buying. Some older dimmer switches (designed for incandescent or halogen loads) may also need to be upgraded to work correctly with LEDs. If you're experiencing flickering or buzzing with LED bulbs on a dimmer, the dimmer itself may be incompatible. BRANZ has useful guidance on electrical compatibility in homes.
Safety Considerations
Halogen bulbs run extremely hot and have been linked to fire risks when used in enclosed fittings or near insulation. If you have downlights with halogen bulbs in a ceiling with insulation above, this is a genuine fire hazard — switching to LEDs (which run cool) is strongly recommended. Always ensure any downlight fitting is rated for the bulb type being used.
When to Call a Professional
Simply swapping a bulb in an existing fitting is something any homeowner can do safely — just make sure the power is off first. However, any work involving wiring, installing new light fittings, adding circuits, or modifying your switchboard is restricted electrical work under New Zealand law. This work must be carried out by a registered electrician and requires a Certificate of Compliance (CoC).
The Electrical Workers Registration Board (EWRB) maintains a register of licensed electricians in New Zealand. If you're unsure whether your job crosses into restricted work territory, it's always safer to ask a professional. You can find qualified local electricians on tradedirectory.co.nz.
Making the Switch to LED
If you still have halogen or incandescent bulbs in your home, now is a great time to start replacing them with LEDs as they burn out. You'll find a wide range of LED options at Bunnings and Mitre 10. Look for bulbs with the right base fitting (E27 screw, B22 bayonet, GU10, etc.), the correct lumen output for your needs, and a colour temperature that suits the room.