Solar and gas in Perth: when to keep gas and when to switch everything electric

Perth households with solar often re-examine whether their gas appliances still make sense. Gas was historically cheaper than electricity for cooking and water heating. With solar generation available during the day, the equation changes — but so does the complexity of your energy setup.

The gas supply charge: the fixed cost you pay regardless

Every gas account in Perth has a supply charge — a fixed daily cost regardless of how much gas you use. In 2026, the gas supply charge for Perth residential customers varies by retailer but is typically $0.55–$0.75 per day (~$200–$275 per year).

This is the critical number: If your annual gas consumption is low (you use gas for cooking only, or just for hot water and cook rarely), you may be paying more in fixed supply charges than the gas itself costs. For low-gas-use households, eliminating the gas connection can save $200–$275/year just in supply charges.

Who should keep gas:

• Households with gas ducted heating (the cheapest heating option in Perth households without solar or without a heat pump)
• Very high gas consumption (large family, frequent cooking, pool gas heater)
• Households where the gas appliances are new and still have many years of life

What each gas appliance costs to replace

Gas hot water → heat pump hot water: A heat pump hot water system (A.O. Smith, Rheem, Sanden, iStore) extracts heat from ambient air and is 3–4× more energy-efficient than resistive electric heating. In Perth:

• Gas hot water annual running cost: approximately $350–$500
• Heat pump hot water annual running cost: approximately $80–$150 (on solar and off-peak)
• Heat pump installed cost: approximately $2,500–$4,500
• Simple payback on running savings plus supply charge elimination: approximately 3–6 years

Gas cooktop → induction cooktop: Induction is 90% efficient (vs 40–55% for gas). Running costs on solar are near zero.

• Induction cooktop cost: $600–$2,000 (quality mid-range options start around $800–$1,200)
• Standard electrical connection required (usually already available in kitchen)
• Cast iron or stainless steel cookware required (induction-incompatible aluminium and copper need replacing)

Gas heating → reverse cycle: Reverse-cycle air conditioning is 3–4× more efficient per unit of heat than gas. In Perth's mild winters (moderate heating demand), reverse cycle is a cost-effective replacement.

• Gas ducted replacement with reverse cycle: $6,000–$15,000 (new ducted system)
• Alternative: add multi-head split systems to primary rooms ($4,000–$10,000) and use existing gas ducted as backup/occasional use

The full electrification pathway

A fully electric household eliminates:

• Gas connection supply charge (~$200–$275/year)
• Gas consumption costs
• Gas appliance service/maintenance costs

And adds:

• Higher electricity consumption (heat pump and induction use electricity, now partially covered by solar)
• One-time appliance replacement costs

The financial case: For a typical Perth household switching from:

• Gas hot water → heat pump
• Gas cooktop → induction
• Keeping existing reverse-cycle (or adding multi-head splits)

Cost savings:

• Supply charge elimination: $250/year
• Hot water running cost reduction: $300/year
• Cooking cost on solar: ~$100/year reduction

Total annual saving: approximately $650/year Upfront cost: approximately $3,500–$6,000 (heat pump + induction cooktop) Payback: 5–9 years

With solar already installed, the additional electricity draw from heat pump and induction is offset by existing solar generation — making the effective running cost near zero during the day.

When gas remains the better choice

Gas ducted heating: Perth's winters are mild but do require heating. Gas ducted heating costs approximately $0.08–$0.12 per MJ. A comparable electric heat pump ducted system can achieve similar or better economics, but the replacement cost is substantial.

If your gas ducted system is new or mid-life, running it for 5–10 more years while planning electrification makes more sense than immediate replacement.

Gas for cooking preference: Many Perth households have strong preference for gas cooking (temperature control, visual flame, wok cooking). The electrification case doesn't require abandoning preferences — it requires understanding the full financial picture. If you strongly prefer gas cooking, keep it and focus electrification on hot water first (where the financial case is clearest).

LPG properties: If your property uses LPG (bottled gas) rather than reticulated gas, the supply charge structure is different (you pay per cylinder delivery rather than a fixed daily charge). The economic case for electrification may be different — get specific quotes for your LPG consumption.

WA gas retail is competitive

Unlike electricity (Synergy monopoly on the SWIS), WA gas is a competitive retail market. Gas retailers including Alinta Energy, Kleenheat, AGL, Origin, and ENGIE compete on rates and fixed charges. If you're keeping gas, it's worth comparing:

• Retailer rates annually (retailers publish comparison rates via the Energy Made Easy comparison tool)
• Your supply charge vs gas usage ratio — if supply charge exceeds gas usage cost, reconsider the connection

Steps to evaluate your situation

1. Review your gas bill: what is your annual gas consumption (in MJ or GJ) and what is your supply charge?
2. Identify which appliances use gas: hot water, heating, cooking, pool heater?
3. Check appliance ages: hot water system > 8 years old is worth replacing; cooktop < 2 years old is worth keeping
4. Get a heat pump hot water quote: this is the single appliance where the payback is most predictable
5. Model the supply charge elimination: if eliminating gas saves $250+/year in fixed charges alone, the payback on appliance replacement shortens significantly

Gas tariff rates and retailer terms vary. Running costs quoted are indicative for Perth conditions in 2026. Get current retailer rates and appliance quotes for your specific household.