Mortgage adviser Ravi Mehta said he advised his clients to float some of their mortgage only if they knew they could pay it off within a short time, because the rates fluctuated so much. Ms Battersby has got her $50,000 loan down to $16,296.
He advised people to split their loan into different fixed terms because short and long-term rates were determined by local and global markets which varied substantially.
"Fix for different maturities ... they should go for a mix. Like something for one, something for three, something for five years, because no one can predict interest rates."
He didn't expect the one-year rate to rise dramatically in a year, so Ms Battersby could have argued for her two-year term to be at a lower rate, about 5.15 per cent.
Ms Battersby said it was confusing for first-home buyers when deciding what mortgage rate to go with.
Fixed, float or both?
A young couple are buying their first home in Auckland for the average house price of $432,000. They are seeking a 25-year mortgage and have a 10 per cent deposit, borrowing $388,800. Using the mortgage calculator on Sorted.org.nz, we look at their options and John Bolton, of Squirrel Mortgages gives some advice.
Option 1 - half and half
The couple fix half of their mortgage and float the other half, based on the lowest current rates (4.99 per cent for a two-year rate and 5.65 per cent for floating rate).
Repayment: $540 per week
Over 25 years: Total to pay is $703,399 including $314,599 interest.
Rating: B
Mr Bolton says: "We generally recommend clients split their mortgage. This way your whole mortgage doesn't re-price at one time and it's easier to adjust to increases as rates start to rise."
Option 2 - all fixed
The couple fixed the whole mortgage (4.99 per cent for a two-year rate).
Repayment: $523 per week
Over 25 years: Total to pay is $680,639 including $291,839 interest.
Rating: C+
"I'm not a big fan of fixing everything on one term ... when will rates move?"
Option 3 - three-way split
The couple split their mortgage three ways. Eg: One, two and five-year rates. (One-year, 4.95 per cent; two-year, 4.99 per cent; and five-year, 5.99 per cent).
Repayment: $540 per week.
Over 25 years: Total to pay is $702,914 including $314,114 interest.
Score: A-
"Splitting the loan makes it easier to manage rate increases in the future. Although the five-year rate is higher upfront, if viewed over five years it will be a similar cost to the shorter-term fixed rates that will re-price sooner."
Final comments: "Focus less on the rate and more on trying to pay an extra $100 per week. This will save you $95,000 and take 6.5 years off the mortgage. Paying it back quicker is where the real savings are."
Note: The study is based on current rates, sustained for the duration of the mortgage.