Raising the Standard for Heating Design in New Zealand
In New Zealand, heating system design is often based on general guidelines, but nothing is mandatory. Unfortunately, basic or outdated calculations are still common practice across the industry.
By contrast, European countries like Germany enforce strict legal requirements for heating design. It’s illegal to create a central heating system without conducting in-depth calculations that cover energy performance and efficiency. These include full room-by-room and whole-building heat loss reports, matching heat input data, defined design parameters, and commissioning documentation. This level of detail ensures heating systems perform as intended, efficiently, reliably, and safely.
At KE KELIT, we believe New Zealand deserves the same high standards. That’s why we’ve adopted European best-practice design principles for every project we deliver. Each system benefits from advanced 3D thermal simulation modelling, accurate heat loss and output calculations, full thermal analysis, and comprehensive design documentation.
Our in-house engineering team utilises the same sophisticated simulation software as our European counterparts, customised specifically for New Zealand’s unique building materials and construction practices. This approach ensures every KE KELIT system is tailored for optimal performance, long-term energy savings, and dependable comfort.
"To design a high performance central heating system, you must first know exactly how much heat a certain home actually requires."
Getting Central Heating into your project involves a 3 step design process
1.
Determining how much heat your project needs is key to designing an efficient system. Accurate calculations based on room size, insulation, and layout ensure the system performs properly, without wasting energy or compromising comfort.
2.
Selection of heating components and technical design involves choosing the right emitters, heat source, and control systems, all tailored to the specific needs of the building. A well-thought-out design ensures optimal performance, efficiency, and long-term reliability.
3.
Validation is the proof that your central heating system has been designed specifically for your client’s home, optimised for comfort, efficiency, and performance. It includes complete documentation such as construction plans, user instructions for the homeowner, and ongoing maintenance requirements.
STEP ONE:
Making a 3D Model
A 3D model of the building is created and all project specific building information is entered into the thermal calculation software.
This incorporates building materials, window sizes, glazing, insulation values (R-Values), thermal break details, orientation, location, room sizes and ceiling heights.
Environmental data is also entered - without this, the heat loss calculation won’t reflect the actual conditions that the building will be subjected to (and required to perform against).
A detailed room by room heat loss calculation report
This is in accordance with “EN 12831 Method for calculation of the design heat load” and shows how much heat each room will lose and how much heat each room will require.
A detailed overall heat loss calculation report
This, in accordance with “EN 6946 Building components & building elements – Thermal transmittance”, details how much heat will be lost through the building materials, how the overall building will perform and the overall heating requirements too.
STEP TWO:
System Design
Once the heating requirements for each room are known, the design process begins.
This stage is all about striking the right balance, maximising comfort and energy efficiency while carefully considering both upfront installation costs and long-term running costs. It’s a finely tuned process that varies with every project.
Choosing the right heat source is key to ensuring heat is produced as efficiently as possible. Just as important is correctly sizing the radiators or designing the pipe layout for underfloor heating. Both of which play a major role in how well the system performs.
Hot Water Heat Pump Example:
Central Heating systems use water as the ‘medium’ to transfer heat from source to emitter. The lower the required water temperature, the cheaper the system is to run.
To lower temperatures of the water, we can decrease the pipe spacing for underfloor heating systems (which increases the surface area between the pipes and the floor and therefore increases the heat output).
The downside is that this increases the amount of piping required and therefore the capital cost.
Boiler Example:
Water is used as the ‘medium’ to transfer heat from source to emitter. Every incremental degree in water temperature required adds 2% to the operating costs.
If you increase the size (and therefore the surface area) of radiators, this reduces the flow temperature of the water, resulting in lower operating costs. The downside is that a larger radiator costs more upfront.
STEP THREE:
Efficiency & Verification
With the building’s heat loss calculated (Step 1) and the emitters sized and verified to meet that demand, the next step is designing the distribution pipe network—the system of pipes that carries heated water from the heat source to each emitter in the home.
Pipe sizing is critical to both system performance and overall efficiency. Undersized pipes can restrict flow, leading to reduced comfort and increased strain on components. Oversized pipes, while allowing for smaller and more efficient pumps, can increase material costs and add complexity during installation. The goal is to strike the right balance between performance, energy use, and cost.
To ensure this balance is achieved, we verify the entire system using advanced simulation software and detailed calculations. Our pipe sizing is based on EnEv 2009, a proven European standard that ensures the distribution network operates at optimal efficiency, with minimal energy consumption and reliable heat delivery throughout the home.
Support
Once the design is complete, you’ll receive a full set of detailed reports, calculations, and installation drawings—including pipe layouts, equipment locations, system schematics, and wiring diagrams. Your client will also receive a comprehensive homeowner’s manual, complete with system information, a maintenance schedule, and warranty details.
A recommended Installer will walk your client through how to use their programmed system and remain their ongoing point of contact for servicing and maintenance, ensuring long-term performance and peace of mind.
Let’s Talk Heating Design for Your Next Project
Book a meeting with a KE KELIT representative to discuss system options, technical support, and how our solutions can align with your architectural vision.