Heating and Cooling Costs of Dwellings – now available for all 8 capital cities

Homes receive an Energy Efficiency Rating (EER)[1] based on the amount of energy required for cooling in summer and heating in winter to stay comfortable year-round, with higher star ratings indicating greater comfort and lower operational energy costs. We offer a ready-reckoner on our website to estimate the annual costs of gas and electricity for heating and cooling any dwelling – house, townhouse or apartment – of your chosen size. Additional energy costs for ducted systems are separately estimated on the basis of a single-storey house with ducts in its roof space.

Originally established for Canberra ACT (NCC Climate Zone 7), this has now been expanded to include all eight Australian capital cities. The calculations are based on current gas and electricity prices released in July 2024 specific to each location, and include the option of all-electric home conditioning.

Users are able to input a preferred home size between 75 and 500m² to compare the estimated energy costs of heating and cooling a home corresponding to an EER using appliances of varying energy rating. The matrix covers the following five NCC Climate Zones (CZ), and results are indicative of other locations in the same CZ (for example, Canberra values for Armidale NSW and Ballarat VIC in CZ 7):

CZ 1 – Hot Humid Summer, Warm Winter (Darwin)

CZ 2 – Warm Humid Summer, Mild Winter (Brisbane)

CZ 5 – Warm Temperate (Adelaide, Perth, Sydney)

CZ 6 – Mild Temperate (Melbourne)

CZ 7 – Cool Temperate (Canberra, Hobart)


Underlying Assumptions [2]		NATHERS star-band energy index values in MJ/m²
Capital City	Heating to Cooling Ratio	0.5	1	2	3	4	5	6	7	8	9
Adelaide (CZ 5)	50:50	521	450	319	219	151	110	84	64	46	27
Brisbane (CZ 2)	30:70	238	215	166	121	88	66	53	44	35	27
Canberra (CZ 7)	0.85:0.15	958	822	600	432	310	223	161	122	84	47
Darwin (CZ 1)	0:1	809	741	626	535	462	399	340	298	257	219
Hobart (CZ 7)	0.85:0.15	888	720	482	339	252	196	152	117	81	47
Melbourne (CZ 6)	0.75:0.25	523	430	290	199	143	107	81	62	44	25
Perth (CZ 5)	50:50	454	412	304	204	135	97	79	61	43	26
Sydney (CZ 5)	50:50	347	251	136	84	62	50	39	30	22	14

[1] The latest changes to the National Construction Code (NCC) which took effect from 1 May 2024 include the introduction of a minimum 7-star energy efficiency rating for new homes, and a Whole of Home energy budget rating that considers energy use in a home from appliances and equipment.

[2] Underlying Assumptions include NatHERS standard occupant numbers and behaviours, NatHERS star-band energy index values in MJ/m² of heating and cooling combined, and climate-appropriate ratios of heating to cooling to apply appropriate fuels and appliance efficiencies to those combined values. For NCC CZs 2 and 5, these ratios are estimated from the BASIX tables for all NSW NatHERS climate zones on the basis of this source.

Asia-Pacific Solar Research Conference – Melbourne 5th to 7th Dec

Exemplary Energy will be presenting the following three peer reviewed extended abstracts at this year’s event:

Optimising Weather Data Reference Periods for Climate Data in a Changing Climate;
Enhancing Australia’s Weather and Climate Data for Benchmarking Simulations;
Mandatory Disclosure of Residential Energy Efficiency Rating in the ACT.

We are also supporting the event by again sponsoring two student awards:

the John Ballinger Award (for the best student paper in the field of the built environment); and
the Monica Oliphant Award (for the best poster paper by a female student).

A range of international and Australian keynote speakers have now been confirmed, and the Hon. Lily D’Ambrosio will officially open the 2023 APSRC. Lily D’Ambrosio is presently the Minister of Energy, Minister for Climate Action, Minister for Energy and Resources, and Minister for State Electricity Commission.

The Energy Impact of Weather – with Interactive Graphical Presentation

Regular readers will notice an important change in our upcoming monthly Exemplary Weather and Energy Index (EWEI) article interpreting for you the weather in July. The energy index for heating and cooling loads with reference to the long-term climatic mean for each of the 8 Australian capital cities is displayed around the map. This will be presented for the three building archetypes (10-storey office building, 3-storey office building and Supermarket) along with the solar PV simulation results for a 5kW domestic system.

This change further enhances a recent upgrade to our EWEI articles with interactive capabilities to give our readers more control over the information displayed. Readers can easily access and compare specific weather elements and archetype simulation results via a customisable dropdown menu according to their interests and needs. The graphs also allow data to be added or removed from the charts by simply clicking on the legend. This interactive feature streamlines the data visualisation process, to enable a self-tailored analysis and understanding.

The Exemplary Energy team strives to keep our published information relevant and engaging. Your feedback is essential to our continuing improvement, and we would appreciate your thoughts. exemplary.energy@exemplary.com.au

Simulation of Buildings Using Real-Time Weather Data – by Veronica Soebarto

Building performance simulation is often used to assess the performance of an existing building, diagnose the main issues or identify existing problems, and investigate various strategies to ratify the problems and improve the building performance. Although it may seem straight forward, simulating an existing building is actually not simple, because, first, you need to ensure that the model accurately represents the actual building in terms of the geometry, envelope materials used and their thermal properties, as well as all the internal loads and use patterns. The second fundamental step in simulating an existing building is to compare the simulation results to measured data and to calibrate the model to minimize the discrepancies between the two.

In order to do this comparison, it is crucial to use the actual weather data file for the same period as the measured data. This is unfortunately often not done by many building simulators. Instead, they often use a standardised climate data file (e.g. TMY, EPW) that is more readily available. This is problematic, because there is no way you can adequately compare the simulation results to the data from the actual building, if you use a synthetic climate data file. Actual building performance, such as indoor temperature or cooling/heating energy use, is affected by the actual weather conditions; simulation results from running the simulation model with a standardised climate data file will only reflect the building performance as affected by those synthetic weather conditions.

Unless you install your own weather station for the location of the building you are simulating, there is almost no way you can obtain actual hourly weather data file. This is where Exemplary Energy plays a significant role in simulating existing buildings in Australia as they are able to provide the required actual weather data file for many locations in Australia. For more than 20 years, Exemplary Energy has been able to provide actual weather data files for our research at The University of Adelaide where simulating existing buildings is necessary.

Below are examples of the simulated hourly indoor temperatures versus measured data from our previous ARC Discovery Project where we monitored more than 50 homes of older people in South Australia. Exemplary Energy provided the actual weather data file (in EPW) for Adelaide (house 1) and Victor Harbor (houses 2 and 3). As can be seen here, the simulation model well represented the actual building as shown in the simulated indoor temperatures that compared well with the measured data.

Author: Professor Veronica Soebarto

School of Architecture and Civil Engineering

Faculty of Sciences, Engineering and Technology

University of Adelaide

https://researchers.adelaide.edu.au/profile/veronica.soebarto

Veronica joined the University of Adelaide in 1998 after completing a Post-Doctorate Research Associate position at Texas A&M University in College Station, Texas, USA, and PhD and Master of Architecture degrees from the same university. Her research interests span from age-friendly built environment, environmental performance assessments of buildings, building performance simulation, building monitoring, human thermal comfort, to the social dimension of sustainable design.

Images shown in this article are from a paper published in Journal of Building Performance Simulation: Arakawa Martins, L., Williamson, T., Bennetts, H., & Soebarto, V. (2022). The use of building performance simulation and personas for the development of thermal comfort guidelines for older people in South Australia. Journal of Building Performance Simulation, 15(2), 149-173.