If you decide to run your life coaching business from home you should be able to agree with HM Revenue & Customs (HMRC) that a certain proportion of your energy costs is treated as a business expense and set against your earnings.
Talk to your accountant, who will be able to advise you whether or not you are able to claim a deduction for some of the household expenses, and the percentage of the total monthly cost of your energy bills that would be reasonable to treat as a business expense.
Alternatively you can claim a flat rate monthly allowance which varies depending on how many hours business use of your home there is in each month. Note that the flat rate allowance covers all the property related expenses of running your business from home - you can't claim separately for things like rent/mortgage interest and utility bills. There is also a flat rate mileage allowance you can claim for business use of your motor vehicle.
If you enter the proportion of your energy bills here in your cash flow remember to include only the balance of your domestic energy costs when calculating how much you will have to take in drawings to cover you living expenses.
If you decide that you need your own premises you will be billed every quarter for all the gas and electricity you have used in the business.