Buying an apartment

Key points

  • Buying an apartment is an increasingly popular way to own your own home, especially in cities.
  • Buying an apartment can mean you are more limited in your design choices than for a freestanding house, but knowing the sustainable design features to look for will help ensure your home will be thermally comfortable and efficient.
  • Look for sustainable design features both in the apartment building, and in the apartment itself.
  • Features you can look for in the building include its energy ratings, energy-saving measures such as efficient lighting and air-conditioning systems, low-water-use gardens, and solar photovoltaic (PV) systems.
  • Features you can look for in the apartment include good orientation and daylighting, appropriate glazing, and energy-efficient hot water systems, air-conditioning and appliances.
  • Also look for an inclusive, consultative, sustainability-focused owners corporation and (if applicable) building manager.
  • If you decide to buy the apartment, get involved with the owners corporation and see what sustainability upgrades could be made to the building.

Understanding buying an apartment

Buying an apartment (also known as a unit or flat) means buying one part of a larger, multi-apartment building or complex. You own the apartment itself (usually defined as everything from the interior surface inwards), and also have shared use and access to common property (for example, entrances and foyers, carparks, stairs, corridors, and gardens) and services (for example, lifts, lighting in common areas).

This chapter looks at buying an existing apartment. For more information on buying an apartment off the plan refer to Buying a home off the plan.

Buying an apartment is usually cheaper than buying a freestanding house, and apartment living suits many lifestyles. However, you are often restricted as to the extent and type of changes you can make to your home.

A two-storey apartment building with balconies that overlook the communal pool area

Apartment buildings can feature communal spaces such as gardens, gyms, and pools

Photo: TVS architects

Ownership and responsibilities

Ownership for apartment buildings in Australia is usually under ‘strata title’. Under strata title, an owners corporation (sometimes known as the body corporate) is responsible for managing common property. Most common property upgrades need to be approved by the owners corporation.


Owners corporations may have rules about the changes that can be made to individual apartments. Before you buy, it’s worth finding out about the owners corporation and their attitude to environmental sustainability in the building.

Energy used within an apartment, such as electricity for appliances and gas for cooking, is usually separately metered and paid for by the occupants. Energy used for central hot water systems is usually paid for by occupants based on individually metered hot water use. Energy used for common areas, such as corridor and car park lighting, is paid by owners through annual levies or owners corporation fees, usually in accordance with their unit entitlements. The way heating and cooling is billed will depend on the design of the system for heating and air-conditioning in your building.

In many apartments, there is only a single water meter for all water consumed and residents do not see an individual water bill. In some places the cost may simply be equally divided among all the units; in others, it may be allocated according to unit entitlements based on the number of bedrooms and physical location in the property. Newer buildings may have individual water meters for apartments.

Apartment options

One innovative option in multi-unit housing is collaborative housing refer to the Case study for more information. In collaborative housing, residents can buy and develop land as a group to produce their own strata-titled apartments. Because there are no developers and no investors, profit margins and marketing costs are removed from the housing costs. The development of shared facilities also helps to reduce costs. Delivered via this model, apartments can cost 25–30% less than a similar apartment in the same area (in cities with very high land costs like Sydney, the savings may be less) (Sharam et al.).

Collaborative housing is well established in northern Europe and parts of the United States. It is relatively new to Australia but is gathering momentum.

Aerial photo of the Commons building located in Melbourne. On half of the top of the first floor is an outdoor courtyard whilst behind it the building continues up several levels with a vertical garden growing up the side of the building.

The award-winning ‘Commons’ collaborative apartment building in Melbourne

Photo: Trivess Moore

Dual key apartments are another recent innovation that provide a good way to cater for change as households grow, downsize, or need to accommodate an elderly relative. They have a self-contained studio inside the main apartment, and typically there is a shared entry area through which all occupants enter. This layout enables a single household to occupy the whole space, or 2 households to share while retaining some privacy. Dual key apartments are common in parts of Europe, Asia and the United States, but relatively new to Australia. One Central Park (see the Case study following) contains several dual key apartments which have proven popular with buyers.

Is apartment living better for the environment?

Townhouses and other attached houses typically use less energy than freestanding houses. But apartment living typically produces more greenhouse gas emissions per person, simply because an apartment typically houses fewer people than a freestanding house.

High-rise apartments use more energy because of centralised building services such as elevators and air-conditioning. Apartments typically use only slightly less water than a suburban home with a garden. At a building level, this is often related to poorly designed and maintained centralised hot water systems, leaks and inefficient air-conditioning cooling towers.

Energy and water use varies greatly depending on the apartment building’s design, how well the building is managed, and the behaviour of the occupants.

In addition, apartments located in urban areas with good public transport can also reduce car dependency and urban sprawl, and offer other lifestyle and environmental benefits.

Comparison of energy use and greenhouse gas emissions across different building types, from a study of 45 buildings in Sydney

Source: Myors et al. 2005

What to look for in a building

Before you look at the apartment itself, you should consider the building in which it is situated. Often, features of the building will have a significant effect on your apartment, so you will need to consider both in your decision making.


Location will be one of the first considerations for choosing your apartment. Think about what you want to be close to. Apartment buildings can often provide better opportunities to be close to public transport, as well as work, shopping and leisure precincts. However, be aware of any downsides such as late-night noise or nearby construction.

Building sustainability features

Do your research on the building’s sustainability credentials and check if there are any sustainable design upgrades planned, in-progress, or recently implemented.

If the building was built in 2006 or later, there is likely to be a Nationwide House Energy Rating Scheme (NatHERS) rating for each individual apartment, indicating how well it performs in terms of thermal comfort.

If the building was built after 2008, check if it has a Green Star rating. This is an indication of the building’s sustainable design and performance. You can also search for apartments with Green Star ratings.

Whether the building is old or new, ask if it has a National Australian Built Environment Rating System (NABERS) rating for apartments, which rates the energy and water efficiency of the common property (or in buildings with a single water meter, the water efficiency of the whole building). A NABERS rating is an important indicator of the running costs of a building.

Check if there have been energy or water audits conducted, and ask to see a copy of the report. Also check insulation levels. Units approved for construction after 2006 are required to achieve minimum thermal performance standards that include insulation; however, many pre-2006 units were not insulated. Some owners corporations and local councils keep records of architectural drawings that may include insulation details.

You may choose to engage an expert consultant to do this research for you, inspect the apartment, and identify potential problems and improvements. It is also wise to conduct a strata search of the owners corporation’s books and records, and there are specialist companies that can do this on your behalf. Ensure this search includes the financial statements presented at the Annual General Meeting. Before purchase, read the by-laws of the owners corporation that are relevant to renovations. Inspection of general meeting minutes (through a strata search) may also give an indication of the ease of undertaking renovations.

Case study: One Central Park

One Central Park is a high-rise apartment building in Sydney that won the ‘best tall building in the world’ award in 2014. It is part of a 5.8 hectare mixed-use high-density infill site in Sydney that incorporates trigeneration onsite and water recycling.

The trigeneration plant uses natural gas to supply electricity, heating, hot water, and air-conditioning to the building and neighbouring sites in the precinct. The decentralised recycled water plant collects wastewater from precinct buildings and an adjacent public sewer, topped up by stormwater and rainwater, and treats it using a membrane bioreactor and reverse osmosis. The recycled water is distributed to the precinct and neighbouring sites to supply cooling towers, irrigation, toilet flushing and washing machines.

One Central Park achieved a 5-star Green Star rating and is best known for its vertical gardens that stretch up the building’s façade, covering 1100m2 and incorporating 383 species, 200 of which are native to south-east Australia. There is also a ‘heliostat’, a structure that reflects sunlight into parts of the site that would otherwise be in shadow.

Each apartment is fitted with smart metering displays to provide residents with interactive real-time information on electricity, gas, and water consumption.

A photo taken from the ground looking up at One Central Park - a modern high rise retail and apartment block - demonstrates its innovative design and external gardens growing on its exterior.

Photo: Sardaka

Building checklist

  • A Green Star rating, if the building is relatively new
  • A NABERS rating (of at least 3 stars and ideally more)
  • Energy-efficient lighting in common areas (for example, LED lights), with appropriate controls such as motion or light sensors
  • Efficient heating, ventilation and air-conditioning (HVAC) plant, including variable speed drives and efficient management systems that monitor energy and water demand in real time
  • Efficient central extractor fan systems for common areas and bathrooms
  • Plumbing in good condition without ‘dead legs’ (piping that has been altered or capped so no water can run through it, causing risk of stagnation and contamination)
  • Effective and well-maintained communal recycling, composting, and waste disposal facilities
  • Spaces and facilities that encourage community-building, such as meeting spaces and community gardens
  • (If a pool is provided) Efficient pool pumps, and (if heated) efficient heating and pool cover
  • Convenient, secure bicycle storage and parking
  • Carparks with efficient lighting, ventilation and carbon monoxide monitoring
  • Charging facilities for electric vehicles
  • Low-water-use gardens and other water-saving measures (for example, rainwater capture, wastewater treatment)
  • Solar PV systems on common property roofs or sufficient suitable unshaded roof area to accommodate a future photovoltaic system
  • Inclusive, consultative, sustainability-focused owners corporation and (if applicable) building manager.

What to look for in an apartment

Thermal comfort

Choosing an apartment that is designed for thermal comfort is particularly important because, compared with a freestanding house, the potential for making improvements can be limited. The NatHERS rating (if available) will give a good indication of how well the apartment is designed to achieve thermal comfort.


Although it is not always possible to achieve optimum orientation in urban, higher density environments, correct positioning of apartments can greatly assist with passive heating and cooling. If possible, choose a north-facing apartment with adequate passive shading and breeze exposure. In tropical climates, orientation to capture cooling breezes is the priority, and also look for good year-round shading. Avoid units with a south only aspect (except for in tropical climates).


Look for a layout that allows functional furniture arrangements and good circulation between rooms while maintaining sound and visual privacy, natural daylight and ventilation. Adequate storage space and access for furniture removal and replacement are also important.

Narrow floor plans and corner apartments can improve cross ventilation and natural daylight, as do ‘crossover’ floor plans where split-level designs can facilitate breeze access through the apartment. However, they can limit access for people with restricted mobility.

Thermal mass

Multistorey buildings usually require dense concrete cores for elements such as stair and lift wells. The location of these high-density concrete elements in the core or as party walls between units can provide thermal mass with appropriate insulation.

The value of thermal mass depends on your climate and how the thermal mass is used. Thermal mass is more useful in temperate or cooler climates, where it can act as a heat bank. In warmer climates and in poorly ventilated units where the capacity for night purging is limited, thermal mass can overheat, causing thermal discomfort.

Windows and glazing

Glazing type, size, and orientation is an important consideration when buying an apartment because of its critical role in thermal comfort, daylighting, natural ventilation, and outlook. External glazing may be difficult to upgrade because it is generally considered common property.

Consider passive design principles when assessing the glazing in units you are inspecting. Avoid apartments with large amounts of west-facing glazing as it will be difficult to install shading on the exterior of the building.

Natural ventilation

Good cross-ventilation allows you to control your thermal comfort and reduces or eliminates the need for energy consuming mechanical systems. Good natural ventilation is usually impossible to achieve in apartments through retrofit. It must be included in the design from the outset through optimal orientation, floor plan, and window configuration.

All rooms should have direct access to fresh air and natural daylight if possible. The building floor plan and cross-section should be designed and orientated to catch and direct local breezes. Landscaping and neighbouring buildings should not inhibit air flow. Avoid large areas of glazing with direct summer sun exposure and without window openings. Useful ventilation solutions include:

  • dual aspect and corner apartments with well-designed openings on at least 2 facades<
  • split-level or crossover apartments that draw in cool air at lower levels and allow warm air to escape at higher levels
  • narrow floor plans (with a small distance between external ventilated facades, ideally the width of 1 room)
  • open-plan living areas with full height doors or openable transom or fanlight panels above (can be retrofitted)
  • windows with maximum opening area and capacity to catch breezes (casement, louvre and bi-fold windows or doors).


Well-designed shading should be integrated into the architectural detailing of the building through the use of balconies, awnings, projections and adjustable louvres. The need to maintain the consistency of the external façade can make retrofitting difficult.

Electrical services, plumbing and appliances

Apartments can have either individual or centralised hot water systems. Individual instantaneous electric or small electric resistance storage systems are common in older units. These should be replaced by more efficient options, if possible (refer to Hot water systems). Centralised systems use a ring main pipe to circulate centrally heated hot water past each unit and back to the source. If ring main pipes are poorly insulated, they can be a source of substantial heat loss. In addition, having a long wait for hot water can be caused by long pipe feeds that extend from the ring main pipe to individual units and do not recirculate. When inspecting a unit, run a tap to check wait times.

If your apartment comes with an individual air-conditioning unit, ensure it is energy efficient. Also consider the energy and water efficiency of appliances and plumbing fixtures. Newer products might still display the energy and water rating labels, otherwise you can look them up at or Lighting can usually be made more energy efficient simply by installing LED bulbs, and good lighting design is ideal.

Potential renovations

Although you cannot alter common property without permission, you do have control over things in the apartment such as appliances, plumbing fittings, and floor coverings. With a clever renovation, you can substantially reduce your apartment’s environmental impact.

Apartment checklist

Here is a checklist of ideal features to look for when choosing an apartment:

  • affordability in your preferred suburb
  • minimum 5 or 6 star NatHERS rating for the individual apartment
  • adequate, controllable solar access to indoor and outdoor living areas
  • practical floor plan
  • well-designed cross ventilation
  • appropriate glazing for the climate and orientation
  • efficient hot water system (if each apartment has its own system)
  • individual meters for hot water (if not from a central system)
  • individual meters for gas (if gas is available)
  • individual water meters (only new buildings are likely to have this)
  • an efficient air-conditioning unit (if included)
  • multi-bin sorters in the kitchen to make recycling easy.

Sustainability upgrades to common property

Many owners corporations are embracing environmental sustainability and undertaking upgrades to reduce their ecological footprint. Most Australian states are investigating changes to strata laws to make sustainability upgrades easier, such as lowering voting thresholds. Take a proactive role in your owners corporation and advocate for sustainable design improvements. Sharing the cost of improvements with other unit owners often makes these changes more affordable and effective.

Why upgrade common property?

Depending on the size of the block, up to 60% of a building’s total energy use can come from common property and equipment.


The City of Sydney’s Smart Green Apartments program found that the average apartment building could make savings of up to 30% through common property upgrades.

A pie graph shows a breakdown of energy use across different building types. Medium and high-rise buildings use 47 per cent of energy for heating and cooling and 27 per cent of energy for lighting. Low rise buildings use a majority of energy for lighting and only six per cent for heating and cooling systems.

Typical patterns of common property energy use.

Source: Adapted from City of Sydney, Smart Green Apartments audits

Opportunities to save water can also be substantial, though in most cases the best opportunities come from focusing on reducing water use inside the apartments. Installing sub-metering can provide a valuable picture of excess water use from common property. The following graph provides a breakdown of how water is typically used in Sydney apartment buildings.

A bar graph illustrates that showers, taps, toilets, leaks and washing machines use the largest volume of water across individual dwellings and common property in Sydney.

Typical patterns of water use in a Sydney apartment building

Source: Sydney Water, City of Sydney

Planning upgrades

There are a number of useful resources that help owners corporations improve the sustainability of their common property. Engaging a qualified professional to
conduct an audit and NABERS rating of your apartment building will show where energy and water is currently used and identify the most cost-effective improvements.

There are also programs and incentives provided by local governments and utilities to help support sustainability upgrades in apartment buildings. Some offer ratings, audits, and upgrade advice for free. Check with your local government or utility to see what they can offer.

Owners corporations can decide which upgrades to do based simply on payback periods, or by targeting a NABERS star rating and using the NABERS reverse calculator to work out the required reduction in energy and water consumption.

Some changes are simple and can be done right away. Others can be factored into the 10-year capital works fund plan, for consideration later when funds become available or when equipment needs to be replaced. The strata committee should consider seeking pre-approval for upgrades with a payback of 3 years or less at a general meeting of the owners corporation.

Energy upgrades

Some of the most typical ‘must do’ common property upgrades are:

  • Lighting – Replace halogen lights (for example, 50W or 35W MR16 or GU10) with LED equivalents. Replace 24 hour fluorescent tubes in car parks and fire stairs with LED equivalents and incorporate integrated occupancy sensors. This can achieve savings in excess of 90% in low-traffic areas. In most cases, the sensor dims the light to approximately 20% of full power when no motion is detected, reducing electricity consumption substantially while ensuring the space is never completely dark.
  • Car park ventilation fans – Install carbon monoxide (CO) monitoring. Fans must run 24 hours a day 7 days a week unless CO levels are monitored. Where CO monitoring is present, fans can be stopped if air quality is acceptable and at least 1 air change is provided per day. This can be done during off-peak billing periods and at minimum speed, minimising energy consumption and cost.
  • Pool heating – If you have resistive element pool heaters, replace these with electric heat pumps. Also consider reducing thermostat temperatures, and installing pool covers to retain heat and reduce evaporation.
  • Condenser water loops – Many older HVAC systems have condenser water pumps that run 24 hours a day, 365 days a year, irrespective of cooling demand. Installing smarter control systems coupled to variable speed drives may mean that these pumps can be slowed or completely shut down for large parts of the year.

A triangular shaped diagram shows that using timers, good up keep and maintenance, energy efficient lighting, heating and cooling are the best ways to save energy in apartment buildings.

Hierarchy of apartment building energy efficiency initiatives

Source: Adapted from Green Strata, 2018

Some other common energy upgrades include (ranked in approximate order of increasing cost or longer payback, though this can vary with each project):

  • optimisation of existing plant and equipment (tuning, timers, settings, maintenance, etc.)
  • lighting upgrades to energy-efficient LED bulbs, timed lighting, and sensors for common areas
  • upgrades to heating, ventilation and air-conditioning (HVAC) (for example, updating old control systems, using variable speed drives to ensure pumps and fans only run as fast as necessary, installing carbon monoxide sensors in car parks so fans do not have to run continually)
  • power factor correction to improve effectiveness of how a building uses its electricity supply
  • upgrades to other mechanical services (water pumps, pool pumps etc.)
  • upgrades to water heating (for example, replacing electric storage systems or centralised gas with heat pumps, solar boosting or instantaneous gas when systems are due for replacement, energy efficient pool heating such as solar thermal or electric heat pumps)
  • installation of a renewable energy supply, after first reducing common property energy consumption (for example solar and wind power). (Note: Although solar PV systems for apartments do not usually produce enough electricity for all the apartments, they can be very worthwhile for capturing energy to offset the energy use for common areas and services.)
  • upgrades to lifts
  • upgrades of the building shell, such as more energy-efficient windows and better insulation.

A triangular shaped diagram shows that using timers, good up keep and maintenance, energy efficient lighting, heating and cooling are the best ways to save energy in apartment buildings.

The owners corporation of this apartment complex upgraded the common area and basement carpark lighting

Photo: Catherine Lezer

Sydney Water has developed a simple calculation that helps owners corporations with a single water meter to determine whether water consumption in their apartment buildings is excessive. Divide the building daily water use by the number of bedrooms across all apartments:

  • Over 300 litres represents high use
  • 200-300 litres is typical
  • under 200 litres is best practice.

Buildings with a higher use and with no obvious leaks on common property are encouraged to retrofit apartments with water-efficient fixtures and fittings. Given the great majority of water use tends to be inside the apartments rather than on common property (typically over 90% according to audits by Sydney Water), this is likely to be the most effective strategy for saving water.

While this can be left up to individual apartment owners, it has proven to be more effective as a whole-of-building initiative organised and paid for by the owners corporation. This is largely because in many strata properties there is only a single water meter for all water consumed, so individual owners have no direct financial incentive to reduce water use. 


Check with your local government or water utility to see if programs are available to assist with upgrades to apartments.

Problems with common property can also lead to excess water use, and installing sub-metering will help to provide a better picture of high-use areas within the building. A plumber can inspect and assess quality, efficiency and maintenance standards for owners corporation facilities. At building management level, excess consumption can often be because there are long delays in hot water arriving at a running tap because of poorly designed and maintained ring main hot water systems. Other typical causes are system leaks and inefficient cooling towers. Pool upgrades can save both energy and water (refer to Energy upgrades above).

Other sustainability initiatives

Other sustainability initiatives that can be implemented by the owners corporation include:

  • organisation of bins and signage to encourage recycling
  • water-efficient landscaping using native plants
  • community vegetable gardens
  • facilities for composting and reusing organic waste
  • convenient bike storage
  • facilities for car sharing, electric vehicle charging
  • community events with a sustainability theme (for example, garage sales or swaps).

A flourishing vegetable garden sits in modular raised garden beds made from corrugated steel.

The residents of this apartment complex built a community garden using funds awarded from a local government grant

Photo: Maeli Cooper

References and additional reading

Learn more


Original authors: Chris Reardon and Geoff Milne, 2013

Updated: Caitlin McGee 2020, Department of Climate Change, Energy, the Environment and Water 2023