energy

To put load into context:  a seven fin column oil heater on maximum uses 1500 watts. This would be expected to heat one medium room (4m by 4m) in a New Zealand home, equating to 93.75 W per m². Passive House aims to use only up to 10 Watts per m². 
Now the same heater has enough strength to heat a whole 150 m².

Then there is demand or how much you will pay. We buy our electric in kilowatt-hours (kWh) and Passive house aims to use 15 kWh per m² of floor area per year.


Comparing two identical Ecotype minor dwellings with 57 m² internal floor area but different energy standards we get:

Building code energy use: LOAD =43 W per m²; DEMAND =85 kWh per m² per year.
Passive House energy use: LOAD= 8 W per m²; DEMAND = 9 kWh per m² per year.

This is achievable through energy efficient glazing and windows, higher insulation values, airtightness and a balanced heat recovery ventilation system.

Building shape and orientation contribute significantly to the energy efficiency of the building envelope. An ‘L’ shape building has more m² of external wall than a square, creating additional heat loss. By optimising building orientation we maximise the solar energy we can harvest through energy efficient glazing, and thereby reduce heating demand and load. 

Energy demand and load requirements are calculated for every home using the Passive House Planning Package (PHPP) software modelling tool, so before your home leaves the drawing board you will know what the outcome will be for the size and shape of your house.