HOMES

HOMES is a building energy optimization model that we created for the University of Otago, New Zealand. It calculates the costs and energy performance of different building designs. Designers, builders, building contractors and others who plan residential building projects in New Zealand can use HOMES to analyze building component and heating appliance options to:

• Estimate the annual heating energy requirement for one or more building designs.
• Calculate the energy savings benefit of increasing building insulation and window double glazing.
• Evaluate the impact of heavy thermal mass in a building on its required energy use.
• Compare the effect of different building orientations on its annual heating energy requirement.
• Determine the Building Performance Index (BPI) of one or more building designs.
• Explore how different heating schedules and set points affect heating energy requirements.
• Evaluate costs and benefits of different building designs.
• Evaluate energy efficiency retrofit options for existing buildings.

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HOMES estimates the heating performance of a building using a database of annual gain and loss factors for locations across New Zealand. It uses the annual gain factors to determine the amount of energy that enters a building through windows from each direction. Similarly, it uses the annual loss factors to calculate a building"s thermal energy losses due to heat transfer from the warm indoors to colder outdoors, and the amount of energy required to warm up a cold building. HOMES calculates the total annual gains and losses for each building design based on the gain and loss factors and adjusting for the impact of the type building components and heating appliances included in the design.

For each building design under evaluation, HOMES calculates the Building Performance Index (BPI), reports the location of heating losses (windows, walls, floors, etc.) and gains (solar gain through windows, internal gain through heating appliances), and calculates the building capital and life cycle costs.

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