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tepeo zeb - choose the right energy tariff

A better boiler powered by smart electricity.

The beauty of a tepeo heat battery boiler is that it charges like a battery and heats like a boiler, giving you total control over when you buy your energy and when you use it to stay warm.

To get the absolute best running costs and make the biggest dent in your carbon footprint, the secret is simple: you just need to pair your heat battery boiler with the right electricity tariff.

Here is our honest, straightforward guide to understanding energy tariffs and finding the best one for your home.

energy tariffs - tepeo zeb

Why flexible tariffs are the key to cheaper heating

Most electricity suppliers now offer tariffs with significantly cheaper rates during “off-peak” hours – usually overnight or in the middle of the day when national demand is low.

Because the ZEB is a heat battery boiler, it doesn’t need to draw power at 7:00 AM when everyone else is making tea and turning up the thermostat. Instead, it quietly charges up during those cheap off-peak hours, storing the heat so your home stays warm exactly when you need it.

Did you know we're an Octopus Smart Tech Partner?

Works with Octopus Energy

Maximise your savings with a heat battery boiler built for the modern grid.

We are officially recognised as a Works with Octopus smart tech partner, designed to integrate perfectly with Octopus Energy’s smart tariffs.

By charging up automatically on cheap, clean off-peak energy, your ZEB keeps your radiators warm and your heating bills down.

Read the Octopus blog post

Understanding the main types of tariffs

Electricity bills are made up of two parts: a Daily Standing Charge (a flat daily fee) and a Unit Rate (the cost per kilowatt-hour of electricity you actually use). When choosing a tariff for your heat battery boiler, it’s the unit rate you want to look at. Here are the main options available in the UK:

Time-of-Use Tariffs

Highly Recommended

Static Time-of-Use

These offer a predictable, much lower rate during set off-peak hours (e.g., 12 AM to 5 AM). EV-specific plans and Economy 7/10 tariffs fall into this category.

Great for the tech-savvy

Dynamic Tariffs

These are tied directly to wholesale electricity prices, which change every half hour. When wind and solar are abundant, prices plummet—sometimes even going negative!

Type-of-Use Tariffs & Others

Not Recommended

Single-Rate Tariffs

You pay the exact same flat rate 24/7. While the ZEB will still heat your home perfectly, you won’t benefit from the financial savings of off-peak charging.

Emerging (Not Available)

Type-of-Use Tariffs

A newer concept where specific smart devices are given a dedicated, cheaper rate. This is an emerging category and is not available just yet.

 




Popular options among ZEB owners today

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Pro tip: Time-of-Use tariffs rarely show up on standard price comparison websites. The EV tariff page on MoneySavingExpert is a fantastic place to start comparing!

The Green Truth: Why off-peak is better for the planet

You might be wondering: what does “off-peak” actually mean for the environment?

It’s a common myth that choosing a “100% renewable” tariff means green energy is always flowing into your home. When national demand spikes (peak times), the National Grid has to fire up fossil fuel power stations, specifically gas, to cope.

Off-peak times are when the grid is quiet, and clean, renewable sources like wind and solar are doing the heavy lifting. By shifting your ZEB’s charging to these quiet hours, you are directly reducing the UK’s reliance on gas power stations.

How to choose the best tariff: The golden rules

For a heat battery boiler to deliver running costs comparable to gas boilers or heat pumps, you’ll want a Time-of-Use or Dynamic tariff. As your trusted advisor, we recommend looking for these two things:

  • At least 4 hours of off-peak pricing: It takes roughly 4.5 hours to fully charge an empty ZEB, so aim for a window that gives you enough time to fill up on cheap energy.
  • The “One-Third” rule: For the best savings, look for tariffs where the off-peak rate is roughly a third of the peak rate (for example, 9p/kWh off-peak vs 27p/kWh peak)

Smart Charging does the hard work for you

You don’t have to be a tech expert or constantly check the weather to get the most out of your ZEB. Our built-in Smart Charging system handles it all for you.

  • It knows what you need: The ZEB looks at the local weather forecast and learns your home’s heating habits, ensuring it only ever charges with the exact amount of heat you actually need for the day ahead. No wasted energy, no paying for heat you don’t use.

  • It hunts for the best price: Our smart algorithms automatically identify the cheapest and greenest periods on your chosen electricity tariff.

With the right tariff and a tepeo heat battery boiler, you get everything you expect from central heating, without the gas. It’s a win for your wallet, and a win for the planet.

Find out more about the ZEB

Find out more

Explore other resources on our website or check if the ZEB is right for you.

Cost & Carbon

Compare the running costs & carbon output of the ZEB to other boilers.

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Hot water solutions

Learn about hot water solutions that would work best for your home.

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ZEB Home Check

Complete our ZEB Home Check to see if the ZEB is a good fit for your home.

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