Estimate monthly repayments and total interest on a green loan, personal loan or mortgage top-up used to pay for a heating, cooling or hot water upgrade.
Use this calculator to compare ways of paying for an upgrade: a discounted green personal loan, a standard personal loan, a mortgage top-up or redraw, or an interest-free plan from a retailer.
How it works. The repayment is the standard level monthly instalment for the amount, rate and term you enter. Total interest = monthly repayment × number of months − amount borrowed. Total repaid adds the upfront fees.
Worked example (illustrative). Borrowing $15,000 over 5 years at 7.5% p.a. gives a repayment of about $300.57 a month, roughly $3,034 in interest and about $18,034 repaid in total. The same amount added to a home loan at a lower rate but repaid over 25 years would cost far more interest in total, even though the monthly figure looks small.
Interest-free plans. Enter 0% and add any monthly account-keeping fee × months as an upfront fee to see the true cost.
Limits. Rates in this example are illustrative. Lenders in the Home Energy Upgrades Fund, banks and other credit providers set their own rates, fees and eligibility. Read the Home Energy Upgrades Fund guide and check the comparison rate and key facts sheet before you borrow.
Worked Estimates and Checklists
An illustrative whole-home gas-to-electric budget for an Australian house, covering reverse cycle heating, heat pump hot water, induction cooking, gas disconnection and the yearly saving.
Costs, Price Factors and 2026 Rebates
How the $1 billion Household Energy Upgrades Fund finances heat pumps and air conditioners through partner lenders, what to compare and how it differs from interest-free plans.
