LED lighting in Perth: the cheapest energy upgrade before solar

Perth homes built between 1990 and 2010 commonly have recessed halogen downlights throughout — typically 50W globes, often 20–40 per house. These are among the least efficient light sources still in widespread residential use.

A 50W halogen produces the same light output as a 5–8W LED. The 42–45W difference, multiplied across 25 downlights running 4 hours per evening, is 4.5 kWh/day — or $545/year at A1 tariff (33.26c/kWh). Replacing those halogens with LED equivalents costs $200–$400 in materials and under an hour's work. The payback period is typically 4–9 months.

If you haven't made this change yet, do it before investing in solar. Reducing your consumption first means you need less solar to offset your bill.

What halogen downlights actually cost

A worked example for a typical Perth home:

• 24 × 50W halogen downlights
• Running 4 hours/evening = 200W × 4hr = 4.8 kWh/day from lighting alone
• Annual consumption: 4.8 kWh × 365 = 1,752 kWh/year
• Annual cost at A1 (33.26c): $582/year

Replace with 8W LED equivalents:

• 24 × 8W = 192W total
• 192W × 4hr = 0.77 kWh/day
• Annual consumption: 281 kWh/year
• Annual cost at A1: $93/year

Annual saving: $489/year. LED replacement cost for 24 downlights at $10–$15 per globe: $240–$360. Payback: 6–9 months.

Heat: the hidden cost of halogens

Halogen globes convert approximately 90% of their energy into heat, not light. This matters in Perth summers:

• 24 halogens running = 24 × 50W × 90% = 1,080W of heat radiating into your ceiling and rooms
• In summer, this adds to your air conditioning load
• The air conditioner runs longer to compensate for this heat source

LED globes produce minimal heat — around 10–15% of energy as heat. Replacing halogens also reduces summer AC load, improving the efficiency benefit beyond just the lighting watt-hours.

A rough estimate: replacing 24 halogens saves 30–60 minutes of air conditioning load per day in summer — an additional 0.5–1.5 kWh/day depending on your AC system.

Choosing LED downlights

Direct replacement vs integrated fittings:

• Direct replacement globes (GU10, MR16): Screw-in or push-in replacements that fit into existing downlight fittings. The simplest approach — replace the globe, keep the fitting. Cost: $5–$15 per globe.
• Integrated LED downlight fittings: Replace the entire downlight with a sealed LED unit. More expensive ($25–$60 per fitting) but eliminates the separate driver/transformer issue on 12V halogen systems, and usually carries a longer warranty (5–10 years).

For MR16 halogens (12V, common in Perth): These run on a transformer (driver). When replacing with LED globes, you also need LED-compatible transformers — the original magnetic or old-style electronic transformers may not be compatible with LED. This is where a licensed electrician is valuable: they can assess whether your existing transformers are LED-compatible or need replacing.

Colour temperature: Measured in Kelvin (K). Lower is warmer, higher is cooler.

• 2,700K–3,000K: Warm white — similar to halogen, good for living areas and bedrooms
• 4,000K–4,500K: Cool white / neutral — typical for kitchens, bathrooms, and offices
• 5,000K–6,500K: Daylight — bright, often used in garages or utility spaces

For replacing halogens, 2,700K warm white most closely matches the look of the original light.

Lumens, not watts: LED packaging is increasingly shifting to lumens (light output) rather than watts (power draw). A 500-lumen LED replaces a typical 50W halogen (which produces about 500–600 lumens). A 600–700 lumen LED is equivalent to a 60W halogen.

Can you DIY?

In Western Australia, electrical work is licensed — replacing a globe (the globe itself, not the wiring or fitting) is legal DIY. Replacing the entire fitting, or changing transformers, requires a licensed electrician.

In practice:

• Replacing GU10 globes in existing fittings: DIY (remove globe, insert new LED globe)
• Replacing MR16 globes + checking transformer compatibility: DIY for the globe swap, but consider an electrician to assess the transformer
• Upgrading from halogen fittings to integrated LED downlights: licensed electrician required

Many Perth electricians offer LED downlight upgrade packages — a job with 20+ fittings is typically completed in 2–3 hours. Get a quote that covers globes/fittings plus labour. All-inclusive cost for 20 integrated fittings: $600–$1,200 depending on the fitting specification.

LED and solar: the multiplier effect

Replacing halogens before or alongside solar creates a multiplier effect:

1. Reduced consumption means more solar generation goes toward other loads (or exports less)
2. Lower peak demand from lighting means the same solar system covers a higher proportion of your total load
3. Heat reduction from LED lowers AC load, compounding the efficiency gain

If you're planning solar and currently have halogen downlights, factor LED replacement into your solar system sizing conversation with installers. A home consuming 22 kWh/day before LED replacement may consume 18 kWh/day after — and the solar system you need is sized accordingly.

Savings figures are based on 24 × 50W halogen globes replaced by 8W LED equivalents, running 4 hours/day at 33.26c/kWh A1 tariff effective 1 July 2026. Actual savings vary by globe count, usage hours, and specific globe wattage.