If the latest campaign promises are to be believed, homeowners will once again be able to get government grants to help insulate their houses, no matter which party wins the current federal election.

Stephen Harper's government is promising to resurrect the hugely popular EcoEnergy Retrofit Program it killed last year, and both the Liberals and New Democrats are now committed to similar schemes.

But homeowners enticed by glitzy election promises of free money for that green makeover may discover that not all the hot air on this issue is what's leaking out of the attic.

Like all home-reno deals, there is plenty of fine print in both the Conservative and Liberal proposals.

The program the Conservatives are promising to revive, for instance, would give homeowners up to $5,000 in grants for everything from insulation to new windows, doors and high-efficiency furnaces.

The grants would be fixed and cover only a fraction of the overall cost — for example, the government grant to replace a window costing hundreds of dollars would be only $40.

That helps to explain why the average homeowner claim under the program since it was launched in 2007 was only about $1,300.

There is one other catch: A homeowner applying for a grant would first have to pay for a professional home inspection, called an energy audit, that generally cost around $400.

Now for the election promises.

The Conservatives are vowing to put $400 million into reviving the program, enough to help 307,000 homeowners across the country.

The fine print is that a re-elected Harper government would only extend the program for one year, and there is almost no chance it will benefit anything close to that many people in that little time.

nl-ignatieff_townhall-300

Liberal Leader Michael Ignatieff speaks in Ottawa April 3, after releasing his party's platform. It includes a home retrofit tax credit to promote energy-efficient homes. (CBC)

Government figures show that even when the program was running at its peak in 2009, it only served about 200,000 homeowners.

And it is certainly not running at its peak now.

The Conservative government started shutting it down a year ago, and most of the professional home inspectors conducting the mandatory energy audits are long gone to other endeavours.

A Conservative government would be lucky to just get the program back up and running in the one-year lifespan they are giving it, much less helping to retrofit more than 300,000 homes.

Liberal plan would run until at least 2017

The home-energy program being promised by the Liberals is better for average homeowners in some ways, and more likely to reach its targets.

The Liberal scheme would last at least until 2017, and would pay 15 per cent of the actual costs of energy-efficient home renos up to a total of $13,500.

That is a maximum $2,025 in grants, compared to the $5,000 limit under the Conservative plan.

But the Liberals say their scheme would be much more flexible for homeowners than the Conservative version, and in most cases the limits don’t matter if the average claim is only about $1,300.

As an added bonus, the Liberal program would also pay half the cost of the mandatory home-energy inspection.

The Liberals say their plan will to help to retrofit 1 million homes over five years at a cost of $400 million a year, the same as the Conservatives are promising for their one-year program.

With the Liberals targeting an average 200,000 homes a year, their retrofit plan would be millions over budget if everyone claimed the maximum $2,025 in grants, plus another roughly $200 for half the cost of the home inspection.

On the other hand, if the average claim stayed around $1,300, the Liberal program could well reach its targets with plenty of cash left over.

Bottom line: For average homeowners, the Liberal plan would provide similar benefit to a lot more people over a much longer period of time than would the promised Conservative scheme better suited to expensive extreme makeovers.