Heat Pump Size Calculator


If you’re looking to find the perfect size heat pump for your home, Rinnai’s easy heat pump calculator tool will help you find the right appliance to ensure optimum comfort in your room. Just select whether you're after a high wall heat pump or a ducted heat pump, fill in the measurements of your room or home and let our calculator do the work.


How do I calculate what size heat pump I need?

The first thing you need to do is to calculate the size of the room you’d like to heat. This means you will have to measure its width, length and height, for our calculator to figure out the total cubic space that needs to be heated. Once you put those details into our calculator, it will provide you with the best sized Rinnai heat pump for your home, designed for New Zealand conditions.

After finding out what size heat pump you need, we strongly recommend you get in contact with one of our Rinnai heat pump dealers to confirm which size unit is best for you. Simply fill out the form here and we'll send one of our trustworthy, authorised dealers to visit your home and provide a free quote


Which size heat pump is right for me?

Use our heat pump guide to help identify which of our heat pumps is right for your space.

How many rooms do you want to heat?

Heat a single room

Heat multiple rooms

Frequently Asked Questions


What size room will a 6kW heat pump heat?

A 6 kW heat pump can heat or cool large open-plan living areas between 27-40 m(with an insulated ceiling up to 2.6 m).

How many kW do I need for my heat pump?

The amount of kW your heat pump needs to heat your room depends on the size of your space, as well as whether you're looking to heat a single room or multiple rooms. Our ducted heat pump units have a higher kW than our high wall heat pumps, as they require more energy to heat multiple rooms to ensure optimal comfort across your home. Other factors that may influence what size heat pump requires include:

- Whether your home is insulated or not. Your heat pump will use less energy if your home is insulated, as this will help your home retain heat more efficiently reducing the heating capacity needed.

- More windows and doors in your room can also increase your heat pump's energy usage as they allow heat to escape more easily, requiring your heat pump to work harder. 

Ceiling height will also influence your heat pump's required energy capacity. The higher the ceiling, the more space there is to heat and cool meaning your heat pump will require more kilowatt capacity.

The climate that you live in. If you live in the North Island your heat pump will require less energy to comfortably heat up a room than if your home was in the South Island. 

How much will it cost to run my heat pump?

The cost of running a heat pump in New Zealand will vary depending on multiple factors, including the size and energy efficiency of a heat pump, the price of electricity from your provider, your temperature settings, the level of insulation at home, your usage patterns and the climate of the region where you live.

You can calculate an estimate of how much your heat pump may cost to run by using the power consumption of the heat pump in kilowatts and multiplying it by the number of hours your unit operates each day to get the daily energy consumption in kilowatt hours (kWh). You can then multiply this number by the current electricity price per kWh to find the daily cost of running your heat pump.

You may find these useful:

Heat Pump Buyers' Guide

Get a Free Heat Pump Quotation