How do you care for your gut? share with nairn's - £300 voucher to be won! Yes, you don't need to be a scottishpower energy customer, or have one of our boilers, to apply for one of our boiler care products find out more about. There's no need for a separate hot water storage cylinder or cold water feed cistern, so they take up much less room than heat-only boilers (below). Flue gases are checked with a flue gas analyser to make sure the boiler is.