Will installing for airtightness save energy and reduce heating bills?
Research shows that we can lose as much as half of all the energy used to heat our buildings through unwanted draughts, inefficient and poor ventilation. We now generally insulate new houses very well but the proportion of energy lost to draughts has increased and in some cases around half of all heat losses are due to air leakage across the building fabric. In Ireland and the UK we are not exposed to extremes in low temperatures, however our climate is exposed to high wind pressure, particularly in coastal regions. If a vapour check has as little as a 1mm tear within a square metre area, the U value can reduce by a factor of 4.8 (See Figure 4.)! This means that the calculated U value is not achieved if the structure is not airtight and hence you need a lot more energy to heat the house. Airtightness does not generally increase U values, but ensures the calculated U value is achieved.
