Heat Pump Sizing Calculator for Auckland Homes
Punch in your room size and how the space is built, and we'll give you a rough kW starting point. Then we'll come out and check it properly.
What are you heating?
How big is the space?
How old is the home?
Sun and exposure in winter?
Our suggestion for your home
This is a guide based on your answers, not a fixed quote. The real answer is a free site visit, where we measure the rooms, check the insulation and confirm the size and price for your home.
Get your sized quote
Send us your details with your calculator result attached and we'll come back with honest options and a fixed price for your home.
A rough guide is about 0.1kW of heating per square metre, so a 30m2 living room needs around 3kW. But an old single-glazed villa needs more and a tight new build needs less. Use that as a starting point, then get the size confirmed on-site before you buy.
How the sizing calculator gives you a number
Measure the floor area of the room you want heated, length times width in metres. Multiply that by roughly 0.1 to get a rough kW figure. So a 24m2 bedroom lands around 2.4kW and a 40m2 open-plan living area sits near 4kW.
That number is a ballpark, not a final answer. It doesn't know your ceiling height, how many windows you've got, or which way the room faces. Treat it as a way to sanity-check what a salesperson quotes you, then let us confirm the real figure before anything goes on the wall.
Why Auckland sizing isn't just about the cold
Our winters are mild but damp. A lot of the work a heat pump does here is pulling moisture out of the air, not fighting hard frosts. That dehumidifying load matters when we size a unit, because a pump that's run flat out heating a cold snap behaves differently to one gently drying out a muggy living room.
Geography changes it too. If you're out in a valley or an inland Franklin pocket around Pukekohe, you'll get colder starts and more frost than someone on the coast at Howick. We factor those cold mornings in so the unit still delivers on the worst days, not just the average ones.
Sizing one room versus the whole house
Heating a single lounge is a straightforward single-head calculation. Once you want bedrooms and a living area all sorted, the maths shifts. You can run one outdoor unit to several indoor heads with multi split heat pumps, and each head is sized to its own room rather than sharing one big lump of capacity.
For a full villa renovation or a new build where you want even heat through the whole place, ducted heat pumps Auckland homeowners choose hide the gear in the ceiling and push warm air to every room. Which way you go depends on your layout and budget, and the different types of heat pump each have their own sizing quirks worth understanding before you commit.
Why an on-site check beats any calculator
No online tool can see your home. We measure the rooms, look at your windows, note the ceiling height and check how the sun hits the space through the day. In an old uninsulated Glen Eden villa that adds up to more capacity than a calculator suggests; in a well-sealed new build it's often less.
Getting the size right upfront also keeps your running costs honest and avoids paying for gear you don't need. When you're ready, book a proper measure-up as part of your heat pump installation Auckland quote, and we'll talk through the heat pump installation cost for the size that actually fits your home.
Common questions about heat pump sizing
What size heat pump do I need for my room?
Start with the floor area in square metres and multiply by about 0.1 to get a rough kW figure. A 20m2 bedroom lands near 2kW and a 40m2 living area near 4kW. That's only a guide though. Ceiling height, windows and insulation all shift it, so get it confirmed on-site before you buy.
How many kilowatts of heating do I need per square metre?
As a rough rule, allow around 0.1kW, or 100 watts, of heating per square metre of floor for a typical Auckland room. Poorly insulated older homes can need closer to 0.12 to 0.15kW per square metre, while tight new builds might get away with less. It's a starting point, not a fixed rule.
What happens if a heat pump is too small or too big?
Too small and the unit runs flat out, struggles to warm the room on cold Franklin mornings, and wears itself out. Too big and it short-cycles, turning on and off, which wastes power and does a poor job of dehumidifying our damp air. The right size sits comfortably in the middle and runs efficiently.
Does insulation and glazing change the size I need?
Yes, a lot. A single-glazed uninsulated villa in Mount Eden loses heat fast, so it needs more capacity for the same floor area. A modern insulated home with double glazing holds heat, so it needs less. That's exactly why we measure and check on-site rather than sizing off floor area alone.
Let's size it properly
We fit and service our own installs across Mount Eden, Glen Eden, Papakura, Pukekohe and Howick. Send us your room details for a free on-site sizing and quote.