Subfloor insulation in rentals a costly mistake
A requirement to install subfloor insulation in rental properties should go and owners who have installed it under
threat should be compensated, Tenancies War spokesman Mike Butler said today.
Insulation features in “healthy homes” regulations that Housing and Urban Development Minister Phil Twyford is expected
to impose next month.
Under existing law, New Zealand’s 262,000 owners of rental property are required to install both ceiling and underfloor
insulation by July 1 or face a penalty of $4000 payable to any person who reports non-compliance.
The cost of installing R 1.3 subfloor insulation as required by the Residential Tenancies (Smoke Alarms and Insulation)
Regulations 2016 for most of the North Island was $881.64 for a 77 square metre dwelling.
The requirement for subfloor insulation is ridiculous because at best it reduces heat loss by only 9 percent which means
the cost of installing it substantially outweighs any benefits, 
Mr Butler said.
Ceiling insulation reduces heat loss by 35 percent but the difference between ceiling and subfloor insulation was not
considered in the cost benefit analysis done by the New Zealand Institute of Economic Research for the Government, he
When asked why, an NZIER spokesman said that the Ministry of Business Innovation and Employment asked them to leave it
out of the analysis, Mr Butler said.
Requiring subfloor insulation in rental properties was a policy blunder perpetrated by the former National-led
Government that should be remedied, he said.
The Minister has rectified another costly failure by the former Government by amending a methamphetamine contamination
threshold that was 24 times lower than the lowest level that anyone could plausibly have a health risk, Mr Butler said.
Mr Twyford could include in the “healthy homes” standards a similar correction by dropping the requirement for subfloor
insulation, he said.
Owners who have installed subfloor insulation under threat based on faulty advice require compensation, Mr Butler said.
A repeal of the subfloor insulation regulation could save the Government millions of dollars in work not required for
any state houses that may not have subfloor insulation, he said.
Stop the War on Tenancies is a group that since last October has been highlighting the evidence that successive
governments have ignored while creating rental property policy.
The proposed Healthy Homes Regulations: An assessment, Ian Harrison, p17. http://www.tailrisk.co.nz/documentlist