His comments follow a survey that showed high-income earners were more likely to use the Government's home insulation subsidy.
The Warm Up New Zealand scheme provides government grants of up to $1300 towards a third of the cost of insulation and a $500 grant for clean heaters.
Community Service Card holders can get more funding.
The online survey of 1578 homeowners was paid for by the Business Council for Sustainable Development.
It found only 1% of homeowners earning more than $200,000 had applied for the subsidy but 45% planned to apply.
Of those making $70,000-$100,000, 35% planned to apply for the subsidy, as did 29% of those earning between $100,000 and $150,000.
Fifteen percent of people earning between $20,000 and $30,000 planned to claim the subsidy.
Business Council chief executive Peter Neilsen told the New Zealand Herald the results showed many people could not afford the difference between the subsidy and the full cost of insulation.
Mr Brownlee said over 8000 houses had been insulated under the scheme.
While it was a "superb result", even more important was that 57% of those houses belonged to low-income New Zealanders.
"The scheme is delivering to a lot of low-income New Zealanders right now.
"It's been a great scheme, very successful," Mr Brownlee told reporters today.
The Government announced in May's budget $323 million over four years to retrofit 180,000 homes with insulation and clean-heating devices.
