UK households looking for simple ways to manage their energy use this winter are being advised to make better use of unused space in their freezers. One suggestion is to fill sealed bags with water and place them in empty areas, although the tip is not a guarantee of a specific saving.
How the Water Bag Freezer Trick Works
The idea is based on reducing the amount of warm air entering the appliance when the door is opened. A freezer with more contents has less empty air space, meaning there is less warm air to cool after each opening.
Savings expert Sam Whillance, from discount platform Deal Town, said a fuller freezer can reduce the amount of warm air that enters when the door is opened. When the door is opened, warmer air from the kitchen replaces some of the colder air inside. The freezer then has to cool that air again.
For households with significant unused space, Whillance suggested using sealed freezer-safe bags filled with water to occupy some of the gaps. Reusable ice blocks or bags of ice can also be used.
Leave Room for Water to Expand
Anyone trying the method should take care when freezing water. Water expands as it turns into ice, so bags should not be filled completely. They should also be strong enough to withstand freezing without leaking.
The bags should be positioned securely so they do not obstruct the freezer door, drawers or internal air vents. There is no need to buy additional food simply to make a freezer fuller.
Leftovers Can Make Better Use of Freezer Space
Households can use spare freezer capacity by freezing leftovers before they spoil. Food should be stored in suitable containers or freezer bags and labelled with the contents and date. Keeping older items visible can also help prevent food from being forgotten and eventually thrown away.
Bulky foods can sometimes be flattened into suitable reusable freezer bags, creating more usable space without blocking the appliance’s vents.
Keeping the Freezer Door Closed Can Also Help
The amount of time the freezer door stays open can affect how much warm air enters. Knowing where different foods are stored can make it easier to find items quickly. This can reduce the time the door remains open.
Households should also check that the door closes properly and that seals are in good condition. Internal air vents should remain clear so that cold air can circulate as intended.
The Tip Does Not Guarantee a Specific Saving
Filling unused freezer space with water is best viewed as a small energy-saving measure, rather than a way to significantly reduce an electricity bill. The amount of energy used by a freezer depends on several factors, including its size, age, efficiency, temperature, location and how frequently the door is opened.
A fuller appliance may have advantages when it comes to the amount of warm air that enters, but the technique does not mean every household will see a particular reduction in energy costs.
Interest in Energy Bills Is Rising
The advice comes as households prepare for colder weather and potentially higher heating and electricity use. Analysis of UK Google search data by OKPromo, cited in the report, found searches for “energy bills” were 64% higher between August 28 and September 26, 2026, compared with the same period in 2025.
Cristian Constantin of OKPromo said to Express that the increase suggested that energy costs were returning to consumers’ attention as colder weather approached.
Small Changes Can Help Households Manage Energy Use
Households do not need to rely on one freezer trick when trying to manage electricity consumption. Keeping the appliance organised, limiting unnecessary door openings, leaving vents clear and using frozen food before it spoils are simple habits that can help households use their freezer sensibly.
The water-bag method may be useful for people with substantial empty freezer space, but it should not be treated as a guaranteed way to cut energy bills.
