150,000 homes which are not connected to the gas supply grid have been promised improved rights to enable them to switch liquefied petroleum gas (LPG) supplier.
The Office of Fair Trading has secured voluntary agreements from the major LPG suppliers for households relying on this heating method (see our Cheap Heating Oil guide for tips on cutting costs).
Under the agreement, firms must allow domestic bulk LPG users to switch supplier penalty-free if the price rises above a certain level. This amount will vary by provider.
Companies must also make any exit fees that are applicable clear. Previously, many were hidden in terms and conditions.
The OFT says the changes will come into place over the next few months.
Around three to four million households, mainly in the countryside, are not connected to the mains gas grid. A large concentration live in Devon, Cornwall, Northern Ireland and Yorkshire.
Update, 10 April. This article was altered today following updated information from the OFT.