Two decisions, two standards

Picture two neighbours. Both are about to spend a significant amount of money.

The first is considering solar panels for his roof. He calculates. Installation cost, feed-in tariff, self-consumption ratio, module degradation, interest on the capital invested. He builds spreadsheets. He wants to know: when does this break even? After ten years? Twelve? Is it worth it at all?

The second buys an SUV. Two tonnes of kerb weight, fuel consumption in the double digits — or, if electric, a battery pack the size of his neighbour’s entire solar system. Did he calculate? Did he factor in depreciation, insurance, fuel, the tyres that wear faster, the parking spaces that don’t fit? Probably not. It just felt right.

This is not an edge case. It is the norm.

Calculate where it hurts — feel where it pleases

The contradiction is so obvious it almost hides in plain sight. Solar panels are held to a standard of precision that we apply to almost nothing else in life. Every kilowatt-hour is projected, every cent of feed-in tariff evaluated, every cloud over the roof priced in. The solar system must prove itself — financially, ecologically, technically.

The car, on the other hand, gets a free pass. You need the space. You feel safer. You go on holiday sometimes. The kids. The dog. The road conditions.

That an SUV consumes 20 to 30 percent more energy than a comparable conventional vehicle — petrol or electric — is not calculated. That the depreciation of a new car in its first three years often exceeds the entire cost of a residential solar installation — is not calculated. That the total cost of ownership over the vehicle’s lifetime dwarfs the purchase price — is not calculated.

But the solar panels — those have to pay for themselves.

Why we think this way

This is not stupidity. It is not random. It is deeply human. And the psychological mechanisms behind it are well researched.

Solar panels are investments. Cars are consumption. We hold investments to a different standard than consumption. An investment is supposed to pay off — that is the entire point. Consumption is allowed to cost money. It is meant to bring joy, signal identity, project status. The fact that an SUV is also an investment — a spectacularly bad one, with a guaranteed negative return — is quietly filed away. In our mental accounting, it sits under “quality of life”, not “capital allocation”.

The car is a status symbol. The solar panels are not. Nobody at a dinner party asks: “So, how many kWp do you have on your roof?” But the car sits in the driveway. It is seen. It is judged. It tells a story about its owner — or at least the story the owner wants to tell. Big, safe, successful. Solar panels, at best, say: frugal. And frugal is not a compliment in our culture.

Losses loom larger than gains. Behavioural economics calls this loss aversion. The fear of making a mistake with the solar panels — of not getting the money back — weighs more heavily than the prospect of saving money over 20 years. With the car, that fear does not exist, because the loss is accepted as inevitable. Cars lose value. That is just how it is. A solar installation that doesn’t pay off, on the other hand, would be a mistake.

Habit beats reason. Buying cars — big ones, expensive ones — is culturally rehearsed. There are dealerships, test drives, advertising campaigns, financing models, an entire societal apparatus that makes the decision easy and self-evident. Solar panels, for many, are still unfamiliar territory. The unfamiliar breeds uncertainty. And uncertainty breeds the desire for reassurance — for payback calculations, warranties, expert opinions.

The numbers nobody wants to hear

Let us do for the SUV what is never done — let us calculate.

A typical mid-range SUV costs between €40,000 and €60,000 to buy. The total cost of ownership over ten years — depreciation, fuel or electricity, insurance, maintenance, tyres, taxes — easily reaches €80,000 to €100,000. The “return” on this investment is negative. Deeply negative. What remains is a ten-year-old car worth perhaps €10,000.

A typical residential solar installation costs between €10,000 and €20,000. Over 20 to 25 years, it produces electricity that — depending on self-consumption and feed-in tariffs — saves two to three times the original investment. The return, depending on conditions, is 5 to 10 percent per year. No speculation. No risk. Just sunlight.

And yet the SUV is bought without a second thought, while every cent of the solar installation is scrutinised.

It is not about logic

If you treat this contradiction as a problem of logic, you misunderstand it. It is not a problem of logic. It is cultural, emotional, and deeply tied to identity.

We live in a society that rewards consumption and mocks frugality. That confuses freedom with size and reason with sacrifice. Where a car is a promise — of independence, safety, adventure — and a solar installation is a maths problem.

This is changing. Slowly. For some.

But the contradiction will only disappear when we stop thinking like accountants about solar panels and like dreamers about cars. When we start asking the same question about both decisions:

What does this really cost — and who pays?

Because the cost of the SUV is not borne by the owner alone. It is borne by everyone. In emissions, in space consumed, in noise, in wasted resources, and in an infrastructure that must be dimensioned around the largest vehicle rather than the smartest solution.

Solar panels, by contrast, generate a benefit that extends beyond the owner. Every kilowatt-hour that comes from a rooftop does not need to be generated from gas, coal, or uranium. It relieves the grid, lowers electricity prices, and reduces emissions — including for the neighbour who is still running the numbers.

Maybe the wrong question

Perhaps “When will my solar panels pay for themselves?” is not the interesting question at all.

The interesting question would be: When will my SUV pay for itself?

The answer is: never.