July and August are historically the cheapest months for heating oil in the UK, typically 10–20% below winter peaks. If you have tank capacity, filling up in summer is the single most effective way to reduce your annual fuel bill.
Why heating oil prices change throughout the year
Unlike mains gas, heating oil is an unregulated commodity. Prices move with global crude oil markets, currency exchange rates and Crucially for UK buyers — seasonal demand. When everyone needs oil at the same time, prices rise. When demand falls away, suppliers compete harder and prices drop.
The UK heating season runs roughly October to March. During this period, demand for kerosene surges across the 1.5 million oil-heated homes in England, Scotland, Wales, and Northern Ireland. Suppliers' delivery schedules fill up, and the wholesale price premium for immediate delivery pushes retail prices higher.
From April onwards, demand drops sharply. Suppliers have excess capacity, delivery slots are plentiful, and they're more willing to sharpen their margins to keep tankers moving. This is the window buyers should exploit.
Month-by-month price guide
| Month | Typical price level | Verdict |
|---|---|---|
| January | High. Peak demand | ❌ Avoid if possible |
| February | High. Still cold | ❌ Avoid if possible |
| March | Softening. Demand easing | ⚠️ Watch and wait |
| April | Falling. Shoulder season | ✅ Good time to buy |
| May | Low-medium | ✅ Good time to buy |
| June | Low — summer trough begins | ✅✅ Very good |
| July | Lowest of the year (historically) | ✅✅✅ Best month |
| August | Low — close to July | ✅✅✅ Best month |
| September | Starting to rise | ✅ Still reasonable |
| October | Rising. Season starts | ⚠️ Borderline |
| November | High. Heating season | ❌ Avoid if possible |
| December | High. Peak demand, cold snaps | ❌ Worst time to buy |
These are historical patterns. In any given year, global events can override seasonal trends. The spike in early 2026 driven by Middle East supply disruption is a good example of when the seasonal rule broke down, but over a 5–10 year period, summer buying consistently delivers savings.
The sweet spot is to order when your tank is at 25–30% capacity, which is typically around June or July for most households that heated through winter. This gives you flexibility to time your purchase without running dangerously low.
How much can you save by timing your purchase?
On a 1,000-litre order, the difference between winter peak pricing and summer trough pricing typically ranges from £80 to £180. On a 2,000-litre fill, that saving doubles.
The exact saving varies by year depending on crude oil prices, but BoilerJuice's published price data shows an average summer-to-winter price difference of around 12–18p per litre over the past five years. At 1,000 litres and 5% VAT, that's a realistic saving of £126–£189 by choosing to fill up in July rather than January.
What if you can't wait until summer?
If your tank is running low in winter, you don't have the luxury of waiting. In that case, the priority is comparing suppliers rather than timing. Prices can vary by 8–12p per litre between suppliers on the same day in the same postcode. Using a comparison tool to check all suppliers before ordering can offset much of the seasonal premium.
As a rule of thumb: if you have more than 200 litres left, you have time to compare. If you're below that, order immediately from whichever supplier can deliver soonest, but still use the quote tool to avoid the most expensive option.
Should you set a price alert instead of timing it manually?
Price alerts remove the guesswork entirely. Rather than trying to predict when prices have hit their seasonal low, you set a target price. Say 85p per litre for 1,000L, and get notified automatically when any supplier in your area hits that level. This is particularly useful if you have the tank space to wait but don't want to monitor prices daily.
We'll email you the moment kerosene drops to your target price. Free, no spam, unsubscribe anytime.
Does buying more at once save money?
Yes — consistently. Suppliers price larger orders lower per litre because the delivery cost is spread across more fuel. On average, 1,000 litres is 2–4p per litre cheaper than 500 litres from the same supplier on the same day. If your tank holds 1,500 litres and you currently order 500L at a time, switching to full-tank orders saves money twice: through the volume discount and through better timing flexibility.
See our guide to 500L vs 1000L — which is better value for a full comparison with worked examples.
Group buying. A further 1–3p per litre saving
If your neighbours also use heating oil, coordinating orders so the tanker delivers to multiple houses on the same road is one of the most underused money-saving strategies in the market. Known as community or group buying, this typically saves an additional 1–3p per litre. Some rural villages have established oil-buying clubs that coordinate quarterly orders. It's worth asking locally whether one exists in your area.
Summary: the four rules of smart oil buying
- Fill up in summer. July and August offer the lowest prices of the year in most years. Don't wait until winter.
- Order more at once. 1,000L beats 500L on price per litre every time. Use your tank's full capacity.
- Always compare suppliers. Even in summer, prices vary significantly between suppliers on the same day. Never order from just one without checking the others.
- Use price alerts. Let technology do the monitoring. Set a target and buy when it's hit rather than trying to call the market.