The EV Gateway: Savings That Snowball

After months of research and a waiting list, in summer 2020, we got our first electric vehicle (EV). I didn’t realise it then, but I was starting down a path that would transform our entire home.

It started innocently enough. The EV was brilliant, and once you start thinking about where electricity comes from and comparing tariffs to find the cheapest rates, solar panels become very compelling. By summer 2022, a 3.3 kWp solar array was on the roof.

Solar led to the next logical step. In summer 2023, a 13.5 kWh home battery arrived to store excess solar or capture cheaper electricity from the grid for expensive periods. Having solar, a battery, and an EV made me realise I had almost fully transitioned to electricity, bringing my gas usage into focus. How much I was still spending on gas became painfully clear: the standing charge alone was £125 per year before any usage. With my solar/battery/EV tariff in place, I could easily calculate the savings from going fully electric.

In winter 2023, the gas boiler came out, replaced by an air source heat pump (thanks to a grant from the Boiler Upgrade Scheme) and I stopped using gas. A few months later we were disconnected from the gas network entirely.

Two Years, Fully Renewable

Over the past two years, I’ve powered everything in our 5-bedroom house (family of 4) on renewable energy. The whole house, all heating, hot water, and around 13,500 miles a year of driving. The solar panels generated about 20% of my total electricity needs (household and car combined). The rest came from the grid, imported from a green energy tariff when renewable generation is highest (typically overnight).

Annual Cost

Looking at the last year, powering the whole home, heating, hot water, and the 13,558 miles of driving has cost:

Total annual cost: £1,021.52

The standing charge alone is £223, something I can’t control.

Each Step Enabled The Next

Each upgrade taught me something that made the next one easier.

The EV forced me to understand electricity tariffs. Solar made me track generation vs. consumption. The battery taught me to shift usage to cheap overnight rates. Each upgrade didn’t just save money, it gave me the knowledge to make the next decision confidently.

But, was it worth it financially?

Return On Investment

I’m realistic about upfront cost. The savings only become “real” once that investment has been repaid. With solar panels lasting 25+ years, batteries 15-20 years, and heat pumps 20 years, the equipment will deliver genuine savings for the majority of its life.

Every home is different, there’s a bunch of variables that would improve or reduce the benefit and savings. Energy prices fluctuate, usage varies, and equipment costs are falling. But for us, I’ve calculated a payback period of 7.5 years, thanks to:

• We’ve eliminated £2,400 a year in diesel costs. Driving now costs 2.4p per mile instead of 15.3p.
• With our new overnight off-peak electricity rate, we learned to shift appliance usage to take advantage of energy at ¼ of the cost.
• After installing solar and then a battery, we shifted even more peak usage to self-produced solar or cheap overnight electricity stored in the battery. By combining all these changes, we reduced our home energy costs by more than 70%.
• Replacing our gas boiler with an air source heat pump for heating and hot water, and pairing it with load shifting and cheaper or self-produced energy, cut our heating costs by 58%. It also meant we could ditch the £125/year gas standing charge entirely.

The breakdown:

I haven’t included the EV in the payback calculation. Despite higher monthly payments, it had no payback period as the £1,800/year savings in fuel plus lower maintenance costs immediately outweighed the additional cost.

7.5 year payback, complete energy independence, and costs I can predict in advance.

That EV in 2020 was the gateway drug, I did not imagine it would lead me here. Best unintentional journey I’ve ever started. ⚡