Designing Central Heating

Central Heating New Zealand Limited offers a start-to-finish design and advisory service for customers installing warm water systems in their home, or for architects recommending such systems to their clients. This section is designed to assist you if you wish to make a head start on this process yourself.

Ideally a central heating system should be incorporated into the initial design of a home, rather than added after the floor plan has been finalized. Provision should be made at the design stage for the area where the heat source will be situated, and the control requirements. Some components should be positioned close to each other – ensuring easy installation, cost savings and general practicality.

Consideration also needs to be given at design stage to the route that pipes or ducts should take through the house or floor slab, and the position of heat emitters (radiators or fan coil units) to ensure optimum heating efficiency and effectiveness.

The principles and guidelines provided here will help you to shape a heating system around the unique style and layout of a home you are designing, and also to bear heating requirements in mind as you design. This adds considerable value to the service you provide to your clients. 
 

General Principles

Because the heating needs of every dwelling are different, the first step when designing a central heating system is to make accurate heat loss calculations based on these important factors:

■ The dwelling size (cubic area), materials used for construction, aspect (ie, north or south facing, etc), the size and number of external walls, and the number of windows and doors. All these factors affect the heat loss of a home. Location of the home within New Zealand is also an important factor, as temperature extremes vary greatly from place to place.

■ Central heating should be designed to achieve World Health Organization recommendations for room temperatures, which are:
      21°C in living areas, kitchens, studies etc with 1.5 air changes per hour
      18°C in bedrooms, hallways etc with 1 air change per hour
      22°C in bathrooms with 2 air changes per hour

■ NB: The WHO recommended minimum for any room is 18°C

■ Adequate ventilation is very important to ensure high air quality is maintained. However, excessive ventilation causes heat loss.

We recommend a system that heats the entire house. The extra installation costs and minimal additional running costs are far outweighed by the benefits and sheer pleasure of being comfortable throughout the house. More of the house will be used and “lived in” if it is comfortable throughout. Its perceived value and attractiveness for future sale will also be increased.