Why Your Current Power Bill Is Probably Lying To You
"I use about 800 units a month."
We hear that sentence almost every day.
And most of the time...
...it's the worst number we could use to design a solar system.
Not because it's inaccurate.
Because it's already out of date.
The Biggest Mistake People Make
Imagine you buy a house with gas hot water.
Gas cooking.
An old wood burner.
No heat pump.
No electric vehicle.
Your power bill says you use around 800kWh per month.
Seems simple enough.
So naturally, you ask a solar company to design a system around 600kWh.
Here's the problem.
That isn't the home you'll be living in five years from now.
Solar Changes The Way People Live
This is something I see all the time.
Someone installs solar.
Suddenly they start making different decisions.
The gas hot water cylinder finally gets replaced with electric.
The old wood burner gets used less because the heat pump is cheaper to run.
Air conditioning suddenly feels affordable.
The spa pool stays on all winter.
An EV arrives in the driveway.
Before long, they're using far more electricity than when they first asked for quotes.
Ironically...
The thing that encouraged them to electrify their home was solar itself.
A Real Conversation
Recently I was designing a system for a homeowner with a large house.
They'd told me they were using around 800kWh per month.
Perfect.
Except...
They also mentioned they wanted to remove their gas hot water and cooking.
They were thinking about adding another heat pump.
The home was large.
Poorly insulated.
And likely to become much more electric over time.
So instead of designing for 800kWh...
We modelled the system around what the home was becoming.
Not what it happened to be today.
The client agreed, and felt a system that generated an average of 1200kWh a month.
… And even then, that was 900kWh in winter, and 1500 kWh in summer.
That was 25 panels. They thought they needed about 18.
And even at 25, because of winter generation - there was a case for more panels. But they wouldn’t fit!
The Cheapest Solar System Is Often The Most Expensive
Let's say we ignore all of that.
We install a smaller system because today's power bill says that's all you need.
Fast forward three years.
You've installed electric hot water.
You've bought an EV.
You've added another heat pump.
Now your solar system is undersized.
Can you add more panels later?
Sometimes.
Sometimes not.
You might run out of roof space.
Your inverter might need upgrading.
The original panels may no longer be available.
The installation costs come back.
Scaffolding comes back.
Labour comes back.
What looked like the cheaper option suddenly becomes the expensive one.
This Is Why We Ask So Many Questions
Some people wonder why we spend so much time talking before requesting quotes.
It's because we're not just trying to understand your power bill.
We're trying to understand your plans.
Questions like these matter:
Are you planning to replace gas hot water?
Will you install another heat pump?
Is an electric vehicle likely?
What happens in a little while when your 3 under 10 are 3 teenagers?
Do you work from home? Is that going to change?
Is retirement around the corner?
Every one of those answers changes how we think about solar.
Because we're not designing a system for last month's electricity bill.
We're designing one for the next 25 years.
The Best Solar Systems Grow Into Their Job
A well-designed solar system shouldn't feel oversized on day one.
It should feel exactly right five years later.
That's why we don't simply plug your latest power bill into software and press "Generate Proposal."
We spend time understanding how your home is likely to change.
Because your current power bill tells us where you've been.
Your future plans tell us where you're going.
And if we're designing a system that's expected to sit on your roof for the next three decades...
We design for the decades. Not for yesterday.
