Study director Prof Philippa Howden-Chapman said she was "pleasantly surprised" with the results.
The findings have been published in the British Medical Journal.
"To get the study independently reviewed and then published in the British Medical Journal gives us real confidence about the way we work.
"I think it shows the benefits of robust research."
The Home, Health and Heating study, which began in 2005, examined 409 children between the ages of 6 and 12 with diagnosed asthma, from as many homes.
The results showed a positive improvement in their symptoms after the installation of better heating systems, including fewer disturbed sleeps, less coughing at night and improved respiratory symptoms, she said.
The study received funding from organisations including the Health Resource Council, Contact Energy, the Ministry for the Environment, Capital Coast District Health Board and the LPG Association.
Prof Howden-Chapman said the research helped to inspire the Government's $1 billion package to insulate houses and install better heating.
"New Zealand is very lucky because we are able to do this staggered research that is not as possible in the UK because of its size," she said.
"We are able to get easy access to records such as the number of days the children missed school.
"It's proved to be a very extensive study which shows the benefits of improved heating, even in areas such as general health and wellbeing."
Prof Howden-Chapman said the study was designed as a practical intervention to improve the indoor environment at the community level.
Part of the funding was used to insulate the 65% of homes not already insulated.
The heating in half the houses was then upgraded before the 2006 winter.
Nurse Teresa Wasilewska from Otago Asthma assisted with the study by providing practical information on how to install heating in their homes and answered their queries about asthma and other respiratory problems.
She said many people involved in the study were spending more on their heating but living better as a result.
"I think it would be interesting to follow up the families tested over the period to see whether they're still practising good habits.
"It's far more effective to heat the whole house at a steady rate, rather than overheat certain areas but leave the rest [of the house] significantly colder."
