Cockroaches and water leaks are just some of the problems experts say people invite by not taking proper care of their coffee machines.

Three fires began in coffee appliances in the ACT in the past year, although the reasons for the fires were not known.

Last week a house was damaged when a coffee machine caught fire and a Civic coffee shop suffered smoke damage from a fire in its roaster in March.

After an investigation, the ACT emergency services agency said it could not confirm an increasing number of coffee-machine fires.

But Canberra coffee-machine repairers said some domestic users do not take proper care of their machines, inviting potentially fiery consequences.

''Ninety per cent of people's machines that I fix, about 200-300 domestic ones a year … just ignore what I tell them and the cautions,'' Euro Coffee Machine Services owner Steven Gianakakis said.

He said a coffee machine, while usually very safe, could catch fire for a couple of reasons.

''Over the 15 years I've been doing this at least 40 per cent of the coffee machines I've seen around Canberra have cockroaches in them because they like the heat,'' he said. ''With domestic machines they don't get them checked out once a year for water leakages - they have O-rings that get brittle and cause leaks.''

All repairers said a coffee machine was like a car. It needed to be serviced once a year.

RBK coffee repairs owner Paul Reed said all the professional coffee services he examined were well maintained. ''In commercial businesses it's a culture - everyone knows to get their machine serviced and if something's wrong they have my number to call,'' he said.

Former Frozpack supervisor for coffee machine repairs Rocco Pelle said that, while Canberra's professional machines were well maintained, ''all the domestic ones are not looked after, they're supposed to operate them according to the instructions on the manual, but … the owners don't do the proper things,'' he said.

Australia's nationwide coffee craze has continued to grow over the last decade - the Australian Beverages Council announced in 2013 Australians drank 5 billion cups of coffee a year overall, 1 billion out and about and 4 billion at home.

According to a Muffin Break survey of coffee lovers Canberras's drink of choice is a latte, with 30 per cent choosing it as their favourite.