Wairarapa landlords are lagging behind homeowners in taking up a Government offer for free home insulation.
More than 600 owner-occupied properties have been insulated in the region since the scheme began, compared with less than 300 rental properties.
Energy Smart's general manager James Gallagher says this could be because landlords - particularly those owning multiple properties, don't know whether their tenants meet the requirements for the scheme.
"What they need to know is whether their tenants have a Community Services Card," he said.
But some landlords might think asking is "a bit cheeky". "It's a bit like asking someone how much they earn."
Nationwide only a third of the 36,000 homes retrofitted with insulation since the Warm Up New Zealand: Healthy Homes initiative began in September 2013 were rentals. It's estimated more than half of uninsulated properties are rentals.
Under the initiative, homeowners or tenants are eligible for free or reduced cost insulation if they have a Community Services Card and the house is occupied by someone under 17 years or over 65 years.
In some regions people at risk from illness linked to cold, damp housing are also eligible.
Green Party co-leader Metiria Turei said the party predicted the scheme would fail renters and this has been proven true.
"Landlords who are only interested in their immediate profit have no incentive to be good landlords."
She said a warrant of fitness scheme is needed to set a minimum standard for housing and hold landlords to account.
EECA said the initiative should appeal to landlords.
"Getting rental properties insulated is a no-brainer for landlords," said chief executive Mike Underhill.
"Landlords will end up with a higher quality property and tenants are more likely to stay longer in houses that are warmer and more comfortable."