Conservative Leader Andrew Scheer is highlighting his promise to give Canadians a tax credit to help make their homes more environmentally friendly.

The 20 per cent refundable tax credit could be claimed by anyone who spends between $1,000 and $20,000 on energy-saving home renovations.

That would include installing high-quality insulation, high-efficiency furnaces, replacing doors and windows, installing solar panels and upgrading ventilation, heating and cooling systems in an effort to cut energy use.

The Conservatives say the measure would allow Canadians to save up to $3,800 on renovations every year.

"Together, the measures in our environmental plan will allow you to save while protecting our environment," Scheer said Wednesday at a campaign stop in Jonquiere, Que.

A report from the parliamentary budget office estimated the proposed measure would cost the federal government a total of $1.8 billion until 2021-22.

The Conservatives had previously estimated the cost to be about $900 million.

The Conservatives previously announced the two-year program in June as part of their overall plan for the environment, which also includes repealing the federal carbon-pricing regime.

Scheer has said he would stick with the current national target of reducing greenhouse-gas emissions by 30 per cent below 2005 levels by 2030, but his plan for the environment did not include any analysis of how its measures would achieve that goal.

The current national targets would require Canada to cut its greenhouse-gas emissions to 513 million tonnes.

Scheer said Wednesday the Green Homes Tax Credit would reduce greenhouse-gas emissions by 9 million tonnes.

Scheer was asked Wednesday whether the proposed tax credit, given it would cost $1.8 billion, is the most efficient way to reduce emissions.

Scheer said cutting down on emissions by helping Canadians to use less energy is only one part of the announcement.

"The other key part of that is helping make life more affordable for Canadians," Scheer said. "And when Canadians can take advantage of this homes tax credit to make renovations in their home, their own lives will become more affordable as the cost of living is reduced, because their energy consumption will go down."

The Conservatives say that in 2017, buildings accounted for 85 million tonnes, or 12 per cent, of Canada's greenhouse gas emissions.