How heating efficiency affects running cost
Useful heat demand is divided by seasonal efficiency to estimate purchased energy, then multiplied by your price.
Why a quote can differ
Weather, controls, flow temperature, fabric performance, hot water, standing charges and real tariffs matter. A design estimate should come from a competent assessment.
Irish home energy guidance
Use SEAI home energy guidance for current primary information. Grants are deliberately excluded because schemes change.
Illustrative model, not a grant estimate or system design.