Heat Pump Sizing Calculator for Napier Homes
Put in your room size and a few details, and you'll get a rough kW figure to work from. We confirm the exact size when we come and look.
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.
As a rough start, allow about 0.15kW per square metre of floor for a well-insulated room, and more for older Napier homes. A 40sqm lounge often lands around 6kW to 7kW. Older single-glazed places push higher. Always get it checked on site before you buy.
What a sizing calculator can and can't tell you
A calculator gets you in the ballpark. You give it floor area, ceiling height and a sense of how well the room holds heat, and it spits out a kW figure. That's enough to know whether you're looking at a 2.5kW bedroom unit or a 7kW lounge unit.
What it can't see is your actual home. Big west-facing windows, a high raked ceiling, a room that opens straight into the hallway, a draughty old villa in a Meeanee cold pocket. All of that changes the answer. So treat the number as a starting point, not the final call.
Why Napier sizing runs higher than the brochure says
Napier throws two extremes at a heat pump. Summer afternoons hit the low 30s, and winter mornings drop to single digits with a hard frost, especially out on the plains and in the valley where the cold sits. A unit sized only for a mild day will struggle when you actually need it.
The housing stock matters just as much. A lot of Marewa and Taradale homes are 1930s plaster and timber, single glazed, with not much in the walls. They lose heat fast, so the kW figure runs above what you'd size for a new build of the same size. If you're weighing up which unit suits your home, the different types of heat pump each handle these older rooms a bit differently.
One room or the whole house
Sizing a single lounge unit is straightforward. Once you want three or four rooms warm, you've got choices. A separate unit in each room, a multi split heat pump running several indoor heads off one outdoor unit, or ducted through the ceiling.
For a full-house plan, look at multi split heat pumps if you want individual rooms controlled on their own, or ducted heat pumps in Napier if you'd rather even heat through the whole place with hidden vents. Whole-house sizing adds up the load room by room, so it's worth getting us to measure rather than guessing off a calculator.
How we confirm the size on site
When we quote, we measure the rooms, check the glazing and insulation, look at ceiling height and which way the windows face, and factor in where you are. A waterfront home in Napier sizes differently from an exposed spot in Poraiti or Onekawa.
From there we set the kW, sort the best spot for the indoor and outdoor units, and give you a fixed price. You can read how heat pump installation in Napier works and what a heat pump installation cost usually covers before we come out. If you're not sure where to start, ring us on 06 242 4129.
Have a look at our heat pump installation Napier, heat pump installation cost, types of heat pump, multi split heat pumps and ducted heat pumps Napier for more.
Common questions about heat pump sizing
What size heat pump do I need for my room?
For a bedroom around 12 to 15sqm, a 2.5kW unit usually does the job. A typical lounge of 30 to 40sqm often needs 5kW to 7kW. In an older single-glazed Napier home you'll size at the higher end because the room loses heat faster. The safest way is to have the room measured before you buy.
How many kW of heat pump per square metre?
A rough rule is about 0.15kW per square metre of floor for a reasonably insulated room. Bump that up for older plaster and timber homes, high ceilings or lots of glass. So a 40sqm lounge is roughly 6kW as a starting figure, more if the room is draughty or cold-facing.
Is it better to oversize or undersize a heat pump?
Slightly oversizing is safer than undersizing in Napier, because you want the unit to cope with a frosty morning. But a wildly oversized unit short-cycles, wears itself out and doesn't dehumidify well in summer. The goal is correctly sized, not just big. That's why we measure rather than round up.
Does insulation change the heat pump size I need?
Yes, quite a lot. A well-insulated room needs a smaller unit than a leaky one of the same size. Single-glazed windows, bare walls and gaps under doors all push the size up. If you're planning to add insulation or double glazing, tell us, because it changes the kW we'd fit.
Get sized right the first time
We install across Marewa, Onekawa, Taradale, Meeanee and Poraiti. Tell us your rooms and we'll size the unit properly and quote it. Call 06 242 4129.