solid fuel coal fire
"Efficient" is using a coal fire instead of British Gas

Choice is the key to being frugal, thrifty, etc.

Gas companies are stinging people up and down the land, from next week, NO MORE!
Our gas fire is being taken out and a solid fuel coal fire is being fitted. No more relying on gas to heat the home and an extra £90 per month in my family's pocket every month!!!