Pricey connection fees are discouraging households who heat their homes with oil, peat or coal from switching to cleaner natural gas.
A study shows that a flat rate connection fee rather than one that increases with distance from the network could see thousands more sign up.
Connecting to natural gas incurs a fee of €249.70 for any distance up to 15 metres from the network and an additional €51.32 per metre after that.
The study, by the Economic and Social Research Institute, looked at 69,000 unconnected homes within 15-30 metres of the network and found 9,000 of them might sign up under a different pricing policy.
"Although there are many reasons why households do not use natural gas, we find that network connection fees proportional to distance are a key barrier to gas being selected as a home heating fuel among households within 30 metres of the gas network," the authors said.
Half of households, 868,000 in total, use oil, peat or coal, the most carbon intensive fossil fuels, as their primary source of home-heating.
A target of the Climate Action Plan is to switch them to cleaner alternatives.
The ESRI says moving to gas is not ideal as it is still a fossil fuel but notes that plans to replace natural gas with biomethane will make the network less carbon intensive.
The study was published as scientists at University College Cork released research showing that solid fuel burning by households caused air pollution to breach World Health Organisation (WHO) limits in a number of regional towns.
Killarney, Enniscorthy and Birr, where peat, coal and wood are extensively used for home-heating, all had high levels of particulate matter (PM), such as dust, dirt, smoke and soot, during the winter.
PM averaged over 24 hours breached WHO levels on 42pc of the days in Enniscorthy and on four days out of 40 in Killarney. There were no breaches in Birr but "huge spikes" in pollution were regularly recorded in all locations during periods when wind speeds were low.
The lack of breaches in Birr was attributed to stormy conditions throughout most of the surveying period there.
Killarney and Enniscorthy will come under the extended smoky coal ban from this September but the study authors say the move could have limited impact without tackling peat and wood too.
"Future efforts to improve air quality in these towns, and other similar towns, will need to address how domestic residences are heated in general, rather than attempting to discourage the use of one specific solid fuel," they said.
Meanwhile, engineers at Trinity College Dublin are embarking on a project to measure pollution from diesel vehicles while they are being driven amid growing evidence of flaws in laboratory models.
Researchers will use remote sensing and portable measurement systems to take readings from 150,000 vehicles at four points in Dublin over 16 weeks.
Professor Bidisha Ghosh, the project lead, said accurate data was vital as half a million people in the EU died prematurely from air pollution each year.
"The expected reduction in emissions from road transport has not been achieved satisfactorily in Ireland or in the wider EU, owing largely to discrepancies between real-world driving emissions and expected emissions," she said.