Two ways to buy your business energy
Every business energy deal comes down to a choice most owners never really make on purpose: a fixed price, or a flexible one. Get it right and your bills stay predictable and fair. Drift into it by accident, or let a contract lapse, and you can end up paying well over the odds for the exact same units. This guide walks through fixed and flexible energy contracts in plain English, so you can pick the one that fits how your business actually uses power, not just the one that lands in your inbox.
Unlike households, businesses get no safety net from a price cap. When the domestic cap rose on 1 July 2026 to around £1,862 a year for a typical home, that protection stopped at the front door of your shop, office or workshop (source: Ofgem). If you want the detail on that, we have covered what the price cap does and doesn’t cover for businesses. Your rate is whatever you agreed, or whatever your supplier decides once a deal ends. So the contract you pick is doing a lot of quiet heavy lifting on your bottom line.
Fixed vs flexible at a glance
| Fixed deal | Flexible contract | |
|---|---|---|
| Your unit rate | Locked for the term | Moves as you buy blocks over time |
| Contract length | Usually 1 to 5 years | Typically 12 months plus, bought in stages |
| Budgeting | Predictable | Varies with the market |
| Risk | You pay a small certainty premium | Exposed to wholesale moves, up and down |
| Admin | Sign and forget until renewal | Needs active buying, often via a broker |
| Best for | Most SMEs | Large users, often around 1GWh+ a year, and multi site portfolios |
What are flexible energy contracts?
Flexible energy contracts let you buy your energy in chunks over time instead of locking one price in for the whole term. Rather than a single fixed unit rate, you or a broker acting for you buy blocks of energy as the market moves, trying to catch the lower prices and spread the risk across the year.
The trade off is more moving parts. You’re exposed to the wholesale market, so a cold snap or a jumpy gas price can nudge your costs up partway through the year. That’s why flexible energy contracts have long been the preserve of larger users with someone keeping half an eye on the market, rather than the corner cafe.
What is a fixed business energy deal?
A fixed deal locks your unit rate and standing charge for the length of the contract, usually somewhere between one and five years. Your usage still moves month to month, so no two bills are identical, but the price per unit stays put whatever the market throws at it.
For most small and medium businesses, that predictability is the whole appeal. It makes budgeting simple and takes the daily energy market off your desk. If you want to understand how those unit rates and standing charges are built up in the first place, our guide to how business energy tariffs are put together lays it out.
Which works out cheaper for a small business?
There’s no permanent winner here. The cheaper option depends on your usage, your appetite for risk and where the market goes next. A fixed deal can look slightly dearer on the day you sign, because you’re paying a small premium for certainty. A flexible deal can beat it, or lose to it, depending on how prices move over the following months. That gamble is the whole point of flexible energy contracts.
Through 2026 the wholesale market has been fairly flat, and longer fixed deals of two to three years have often priced close to shorter ones (a rough picture that shifts with the market, so always check live quotes for your meter). For a business that simply wants a fair, steady price and no nasty surprises, a fixed deal is usually the easier call. For a fuller look at the options, see our complete guide to business energy contracts.
When flexible energy contracts actually make sense
Flexible energy contracts come into their own when the numbers are big enough to justify the effort. If your site or portfolio burns through a lot of power, often upwards of around a gigawatt hour a year, though every supplier sets its own threshold, the chance to shave the unit rate can outweigh the extra risk and admin.
They also suit businesses with the time, or the adviser, to manage a buying strategy actively, and those spreading risk across several sites. If none of that sounds like you, there’s no shame in keeping things simple. A well timed fixed deal is a perfectly sensible answer for the large majority of SMEs.
The costliest option is doing nothing
Here’s the one your supplier is quietly banking on. When a fixed deal ends and you haven’t agreed a new one, you’re not moved to some friendly default. You’re rolled onto out of contract or deemed rates, which tend to sit a good deal higher than anything you’d agree by picking up the phone (the gap varies by supplier and usage, but it’s rarely small).
Think of it as the business version of the loyalty penalty, ticking away in the background until you open a bill and wince. The fix is boring but it works: know your contract end date, and line up the next deal before the old one lapses. You can compare business energy deals in a few minutes rather than letting the clock run down for you.
How to choose before your renewal
Start with how you actually use energy, not the headline unit rate. A modest, steady user on a tight budget almost always wants a fixed deal. A heavy or multi site user with someone to watch the market may get more from flexible energy contracts. Check your meter type, your usage across a full year, and your renewal window, then compare like for like across suppliers before you commit.
Whatever you land on, land on it on purpose and before your current deal runs out. That single habit, choosing rather than drifting, is what keeps a business off the priciest rates. When you’re ready to see what’s actually on the table, it takes minutes to check.
Key takeaways
- Fixed deals lock your unit rate for the term, usually one to five years, and keep budgeting simple.
- Flexible energy contracts buy power in blocks over time, with more risk and more admin, and tend to suit larger users.
- Businesses don’t get the household price cap, so your contract is your only real protection.
- The most expensive place to sit is out of contract, on deemed rates, so never let a deal lapse.
Frequently asked questions about business energy contracts
- Can I switch business energy supplier whenever I want?
- Not usually mid contract. Most business energy deals run for a fixed term with no cooling off period once they start, so the moment to switch is during your renewal window before the deal ends. Check your end date and any notice terms early.
- Do businesses get the energy price cap?
- No. The price cap covers domestic customers only. Businesses agree their own rates, and if you fall out of contract you can be placed on deemed rates instead, which are usually higher (source: Ofgem).
- Are flexible energy contracts only for big companies?
- Largely, yes. Flexible energy contracts tend to suit higher usage sites and portfolios with someone managing the market. Most small and medium businesses are better served by a straightforward fixed deal, though the thresholds vary by supplier.
- What happens when my fixed deal ends?
- If you haven’t agreed a new contract, your supplier can move you onto out of contract or deemed rates, which are typically more expensive. Agreeing your next deal before the end date is the simplest way to avoid that.
For the official view on getting a better deal and your rights as a business customer, see Ofgem’s business energy advice.
