The State communications regulator is warning that homeowners are having to choose between energy efficiency and mobile phone coverage.
ComReg has carried out a number tests proving that modern insulation can dramatically reduce the strength of mobile phone signal in the home.
The regulator said the materials used for heat insulation and triple-glazed or PVC windows contain energy efficient foils and metallic substances that lessen phone signal.
According to The Irish Independent, the tests found that the use of "more heat-efficient building materials" combined with " a great increase in overall mobile voice and data traffic" has seen a deterioration in the quality of indoor mobile phone performance in many homes.
It found that materials used for roof insulation interfere less with signal.
The regulator is advising homeowners to use home WiFi on their phones where possible.
It also recommended the use of WiFi calling - a system whereby your home WiFi signal is married with that of your phone service - however Eir is currently the only operator offering the service.
The installation of a home mobile repeater is a third option.
The devices boost outside mobile signal indoors - however, they are currently illegal, although ComReg has announced plans to legalise them under certain technical conditions.