For the past decade, home owners who ripped out wood heaters and replaced them with ducted or flued gas heating have been entitled to a rebate of up to $800.

But ACT government figures reveal the rate of uptake has slowed in the past three years. Just 44 subsidies were paid last year after a peak of 250 in 2004 - the scheme's first year.

Heating retailer Mike Bresnik blames the shift back to wood heating on rising power costs.

The government rebate program has been solely funded by ActewAGL since 2006. In 2012, 55 subsidies were paid - down from 59 in 2011 and 94 in 2010.

Mr Bresnik said in the past three years his business had sold wood heaters at the same rate as gas heaters. Both options complied with emission regulations.

As the owner of a firewood supplier and heater retail outlet selling gas, electric and wood heaters, he has a foot in both camps.

''With the majority of people we get into the [heater] store, 50 per cent are disgruntled gas and electricity users … who have been paying $750 to $1250 per quarter,'' he said.

But a spokeswoman for Environment and Sustainable Development Minister Simon Corbell said the rebate program had been ''highly successful''.

Some 1052 wood heaters had been removed since 2004.

''This is a major contributing factor to the significant improvement we have seen in our air quality over the same period,'' she said.

The most recent Bureau of Statistics data, from 2011, shows the percentage of ACT households using wood heaters as their primary heating source dropped from 3.9 per cent (about 5000 households) in 2008 to 2.3 per cent (about 3000 households) in 2011.

ActewAGL asset management general manager Stephen Devlin said gas usage in Canberra noticeably spiked annually around Anzac Day.

However, an ACT air quality report from 2012 showed the amount of particulate matter in Canberra's air had risen to the highest level in four years.

Concentrations exceeded standard advisory levels on three days.

Despite the government's attempts to discourage the use of wood heaters, including an outright ban in new Molonglo Valley suburbs since 2012, Mr Bresnik said Canberrans were still choosing wood heaters to warm their homes.

''[Wood heating] is sustainable, it's renewable and it's carbon-neutral,'' he said. ''There are all these arguments as to why wood heating is good, but no one will debate it properly.

''The government goes on about particulates [in wood smoke] and, yes, they can be carcinogenic, but how many people were admitted to hospital with all the recent [bushfire] burning?''

As with all firewood sellers, Mr Bresnik's business must comply with strict requirements.