What Size Solar System Do You Actually Need for Your Home in Victoria?

What Size Solar System Do You Actually Need

If your electricity bills keep climbing and the grid feels more unreliable every year, you’re not alone — thousands of Victorian homeowners are feeling the same pressure. And with STC incentives scheduled to keep decreasing, every year you wait is literally costing you money. That’s why more families are choosing solar now: it’s a one-time investment that protects you for the next 20–25 years.

System Size Based on Home Type & Usage

Home Type	Typical Daily Usage	Common Appliances	Recommended System Size	Why This Size Works
1–2 Bedroom Home	8–12 kWh/day	LED lights, single fridge, washing machine, TV, 1 split AC	5–6.6 kW	Covers daytime use + keeps bills low without oversizing. Ideal for small homes with stable usage.
3–4 Bedroom Family Home	15–22 kWh/day	2–3 split ACs, dishwasher, dryer, extra fridge, daily cooking	8–10 kW	Most families underestimate usage. 10kW gives comfort, flexibility & supports future appliances.
Large 4–5 Bedroom / High-Usage Home	25–35+ kWh/day	Multiple ACs, pool pump, EV charger, home office equipment	13 kW or higher	Handles morning + evening peaks. Best long-term value for large homes with rising usage.

System Size Based on Your Electricity Bills

Quarterly Bill Amount	Estimated Daily Usage	Ideal System Size	Reasoning
$280–$450	14–20 kWh/day	8–10 kW	You need a system that offsets both daytime & part of evening usage. Smaller systems won’t cut the bill enough.
$500–$800+	24–35 kWh/day	10–13 kW+	High usage means more appliances + longer operating hours. A bigger system protects you from rising tariffs.

How Roof Direction Affects Required System Size

Roof Direction	Output Efficiency	Size Adjustment Needed	Why
North-Facing	Highest (ideal)	No size increase needed	Produces the most sunlight throughout the day.
East/West	Medium	Add 1–2 kW	You get more morning + evening power, but mid-day production is lower.
South	Low	Add 2–3 kW	Least optimal exposure; needs extra panels to compensate.

Appliance Load & Impact on Solar Size

High-Usage Appliances in Your Home	Impact on Solar Size	Recommended System
0–2 major appliances	Low impact	6.6–8 kW
3–4 major appliances	Medium impact	8–10 kW
5+ appliances (ACs, pool, EV, dryer)	High impact	10–13 kW+

Real Home Example: 6.6kW vs 10kW vs 13kW (East/West Roof, $520 Bill)

System Size	Daytime Coverage	Grid Power Needed	Winter Performance	Battery-Ready?	Long-Term Value
6.6kW	Covers basic daytime use	Buys 40–55% from grid	Weak	❌ Not ideal	Low — high regret risk
10kW	Covers main appliances comfortably	Buys 40–55% from the grid	Moderate	✔ Good	High — solid balance for families
13kW	Covers full usage + future loads	Buys 20–30% from the grid	Strong	✔✔ Best for battery	⭐ Highest — future-proof for 20–25 yrs

Expert Pick for This Home is 13kW

Why? The home will likely add an EV, battery, or second AC — so future-proofing saves thousands.

Green Electric Solution

Green Electric Solution has been supporting Victorian homeowners for over 5 years, helping families navigate rising energy bills, changing rebates, and smarter solar choices. With deep local expertise, they design right-sized solar and battery systems that deliver real savings for 20–25 years—without overselling or guesswork. Their strong understanding of Victorian tariffs, roof conditions, and household usage ensures systems that perform in real life. In a crowded market, Green Electric earns trust by focusing on long-term value, transparency, and true energy independence for Victorian homes.

Do You Need a Battery? (Clear, Honest Answer)

One of the biggest questions Victorian homeowners ask is:
Should I get a battery now, or wait?

The truth is simple:
✔ A battery can dramatically reduce your bills
✔ But it is not financially ideal for every household right now
✔ And the right battery size depends heavily on your usage and your solar system size

This section gives you a clear, honest breakdown — based purely on facts, Victorian energy tariffs, and real homeowner savings

You Use Most Power in the Evenings

This is the #1 factor.
Most Victorian families have their highest energy usage between 4pm–10pm, when:

• Cooking happens
• Heating/cooling runs
• Showers and laundry occur
• Kids are home using devices

Peak tariffs during these hours can be 38–45c/kWh, while solar exports earn only 4–6c/kWh.

Pain point:

• You’re buying expensive power at night while selling cheap power during the day.
• A battery flips this upside down — letting you keep your solar energy for yourself

You have a 10kW–13kW Solar System

Batteries work best with larger solar systems because they charge faster and more consistently, especially in winter.

FACT:
Most Victorian homes with 6.6kW systems struggle to fully charge a battery in winter.
A 10–13kW system solves this problem

You Want Protection From Blackouts

Victoria experiences localised outages, especially in:

• new estates
• older suburbs with ageing infrastructure
• storm-prone areas

Only batteries with backup functionality (like Tesla Powerwall, Sungrow, Alpha ESS) can keep critical circuits running

You’re Planning an EV in the Next 3–5 Years

• EV charging at night is a massive bill increaser.
• A battery can supply 20–60% of your EV charging needs, depending on size

You Want Predictable Bills for the Next 15+ Years

Electricity prices rise every year, but battery savings remain consistent. Batteries help you control your evening costs when tariffs are highest

When You Shouldn’t Buy a Battery Yet

Batteries are amazing — but not for everyone right now.
A battery might NOT make sense if

Your Solar System Is Too Small (Under 6.6kW)

You won’t generate enough excess energy to charge a battery fully.
A battery would sit at half charge on many winter days.

Your Daily Usage Is Under 10–12 kWh/day

• Low-usage homes don’t save enough to justify the upfront battery cost.
• You will export more power than you use — and while a battery helps, the payback becomes too long

You’re Struggling With Budget in 2025

• A good battery (10–13 kWh usable) costs $7,500–$14,000 after rebates.
• If stretching your budget makes you uncomfortable, it’s wiser to install a bigger solar system first and add a battery later

You Have a South-Facing Roof With Low Solar Output

Your system may not produce enough excess, especially in winter.
Again — solar upgrade first, battery later

Typical Battery Sizes for Victorian Homes (10–40 kWh)

Most homeowners don’t know what battery size they actually need.
Here’s the breakdown:

Home Type / Usage	Typical Evening Consumption	Ideal Battery Size
1–2 bedroom home	5–7 kWh	10 kWh
3–4 bedroom family	8–12 kWh	10–15 kWh
High-usage home (pool, 2 ACs)	14–20 kWh	15–20 kWh
Home with EV	20–30+ kWh	20–40 kWh

FACT:
Victorian families often underestimate evening usage.
Devices + cooking + heating/cooling = fast battery drain.

• A battery that’s too small results in:
• running out before 9 pm
• still buying expensive peak electricity
• Reduced long-term savings

Sizing correctly from the start is key.

Example Savings From a Real Victorian Home

Home Profile

• 4-bedroom home in Cranbourne
• 2 adults + 2 kids
• Daily usage: 24–28 kWh
• 13kW solar system
• 13.5kWh Tesla Powerwall
• Peak tariff: 42c/kWh
• Feed-in tariff: 5c/kWh

Before Battery

• Quarterly bill: $480–$620
• Exporting ~60% of solar power
• Buying expensive evening power daily

After 13.5kWh Battery

• Quarterly bill: $120-$200
• Nighttime grid usage dropped by 85%
• Battery covers 4 pm–11pm most days
• Backup power during storm outages

Annual Savings

$1,400–$1,900 per year
(depends on usage + tariff changes)

Payback Period

6–9 years, depending on export rules and tariff plan

Why this works:
A 13kW solar system consistently charges the battery → even in winter, battery stays 50–100% full

You should consider a battery if

• You use the most power at night
• You have (or plan) a 10–13kW system
• Your electricity bill is consistently $450+
• You want blackout protection
• You plan to add an EV soon

You should wait if

• Your solar system is small
• Your usage is very low
• Budget is tight
• Your roof orientation limits production

Battery Decision Comparison Table (Victoria – 2025)

Scenario / Factor	Battery Makes Sense	Battery Does NOT Make Sense Yet
Your Daily Usage	20–35+ kWh/day → Evening heavy	Under 12 kWh/day → Mostly daytime
Quarterly Bills	Above $450–$900 → Large night usage	Below $250 → Not enough night demand
Feed-in Tariff	Low FiT (3–5c) → Better to store solar	Higher FiT deals (rare)
Power Outages in Your Area	Frequent outages → Need backup	Rare outages → No urgent need
Roof Size / Solar Size	10kW+ solar installed → Plenty to charge battery	Under 5kW solar → Battery won’t charge efficiently
Future Plans	Planning EV, all-electric home, heat pump, induction cooking	No major lifestyle or appliance changes expected
Financial Payback	7–10 years (high usage homes)	12–15+ years (low usage homes)
Night-Time Usage	AC/heating, cooking, hot water, EV charging at night	No heavy appliances used at night
Budget	Can afford $7,000–$14,000 investment	Budget tight → Solar only gives best ROI
Longevity Plan	Staying in home 7+ years	Selling home soon
Main Benefit	Lower bills, blackout protection, huge long-term savings	Solar alone gives faster payback

Typical Battery Sizes for Real Victorian Homes (Quick Guide)

Home Type	Usage Profile	Recommended Battery Size
1–2 bedroom, light usage	8–12 kWh/day	5–10 kWh
3–4 bedroom family	15–25 kWh/day	10–15 kWh
Large 4–5 bedroom / high usage	25–35 kWh/day	15–20 kWh
EV owners / all-electric homes	30–50+ kWh/day	20–40 kWh

Real Example: Battery vs No Battery (Victoria – 2025)

Scenario	10kW Solar Only	10kW Solar + 13kWh Battery
Annual Bills	~$1,050	~$250–$350
Grid Usage	45–55%	5–15%
Feed-in Benefit	Small due to low FiT (3–5c)	Higher savings because solar is stored
Backup During Outage	❌ No	✅ Yes (4–10 hours depending on load)
10-Year Saving	~$12,000–$15,000	~$22,000–$28,000
Best For	Budget-conscious homes	Families planning long-term savings

FACTS for Victorian homeowners

• Solar panels produce most power between 10 am–4 pm
• Cloudy days still generate 20–40% of the usual output
• Winter production drops by 25–45%, depending on your roof direction
• Modern panels are designed to handle cold, windy Victorian weather efficiently

Pain point solved: Many homeowners worry solar “won’t work in winter.”
The reality?
Solar still generates meaningful power year-round, and a correctly sized system (10–13kW for most families) easily compensates for winter dips.

Battery (Optional) → Stores Excess Energy

This is where the biggest savings kick in.
A battery handles your:

• evening usage
• nights
• grid outages
• peak tariff periods

A larger solar system (10–13kW) charges a battery faster and more consistently, especially in winter

In Summary

• Solar works in Victoria — but you must size it correctly due to winter dips and low FiTs.
• A bigger system (8–13kW) is usually smarter for long-term bill control.
• Victoria’s climate and rules make “old-school 6.6kW systems” obsolete for most families.
• Batteries are becoming more valuable due to peak tariffs and grid issues.
• STC reductions mean waiting will cost more.
  

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