This project used airtightness tests to identify sources of uncontrolled ventilation and cold spots in poor energy efficiency (SAP bands D G) properties in a rural area of Wales, highly exposed to sea winds, often solid walled or other hard to treat (HTT) construction, and most not being served by mains gas. Results of the tests highlighted appropriate airtightness measures which could be installed to address and reduce uncontrolled air exchange, to provide energy savings and improved comfort to the residents, vulnerable to fuel poverty.