"Because of the severity of Berkeley's asthma, whenever he gets sick Rob is on notice ... and if Berkeley's having an attack I need him to come home or meet us at the hospital," Mrs Ballinger-Judd said.
Berkeley's hospital admissions have exhausted Mr Ballinger-Judd's work leave. He now has to take unpaid leave once or twice a month when his son is unwell, which puts extra financial pressure on the family.
"We are already bracing for the increased power bills this winter from keeping the house warm enough to help Berkeley stay healthy," Mr Ballinger-Judd said.
Mrs Ballinger-Judd said her husband's employer was at first understanding about how much time needed to be taken off, but their patience was running out.
The latest figures for the cost of lost productivity to the country by asthma sufferers were in 1999.
In that year the cost was $895 million, including $700 million in non-medical costs such as people missing days of work and school, said Professor Innes Asher, from Auckland University's Faculty of Medical and Health Sciences.
Employers and Manufacturers Association occupational health and safety manager Paul Jarvie said that figure sounded quite conservative and could probably be doubled today.
New Zealand had one of the highest rates of asthma in the OECD, "which is alarming", he said.
"It's one of those elephants in the room where we know it's there but it's almost too big to manage."
It was also up to employers whose workplaces caused or worsened asthma to reduce the danger, such as providing proper ventilation and containing dust and fumes as much as possible, Mr Jarvie said.
Professor Asher said "billions of dollars were lost to society" through medical costs and lost productivity of people missing work and school.
She said good asthma management could change this and called for a national asthma strategy to be developed to ensure every sufferer received the right care.
Some low socio-economic families struggled to pay the $5 prescription charges, which has recently increased from $3, Professor Asher said.
Asthma Foundation medical adviser Kyle Perrin said patients needed to ensure they continued to use medication and keep their illness under control at all times.
"Don't wait until asthma is out of control to do something about it."
By the numbers
* One in four New Zealand children and one in six adults have asthma.
* New Zealand has the second-highest rate of asthma in the world, following Britain.
* People still die from asthma, with 79 deaths in 2006, 61 in 2007 and 65 in 2008.
* About 800,000 New Zealanders are affected by asthma and other respiratory conditions.
* About 550,000 school days in New Zealand are lost each year due to asthma.