What Is a Duplex? A Complete Guide to Buying vs. a House or Townhouse in Sydney

A duplex is a residential building divided into two separate homes with a shared wall. Unlike an apartment, you often own the land your unit sits on, offering a blend of affordability and autonomy. For many Sydney buyers, it represents a more affordable alternative to a detached house while providing more space and privacy than a condo. This guide will help you decide if it’s the right investment and lifestyle choice for you in Sydney’s competitive market.

A duplex is generally best for buyers seeking a balance of affordability and ownership perks, like a yard, without the full cost of a detached house. In Sydney’s market, where the median house price sits at $1.49 million, a duplex can offer significant savings. A house offers maximum privacy and control, while a townhouse often involves more community rules and fees (strata/HOA).

As an experienced custom home builder, building a new duplex in Sydney costs between $400,000 to $700,000 per unit, meaning a full duplex could set you back anywhere from $800,000 to $1.4 million. This is significantly less than Sydney’s median detached house price, making it an attractive option for first-time buyers and investors.

In Sydney’s competitive rental market, where median rental prices hover around $1,000 per week, owning a duplex provides a strong financial edge. If your mortgage repayments are $5,000 per month, but you’re earning $4,000 in rental income from the other unit, you’re effectively living in your home for just $1,000 per month.

A Duplex is Best For: First-time homebuyers looking to enter Sydney’s market below the $1.49 million median, investors (live in one, rent the other for ~$1,000/week), or downsizers who want a yard without the upkeep of a large house.

A House is Best For: Families needing maximum space and privacy who can afford the premium (median $1.49 million in Sydney), and those who want full control over their property.

A Townhouse is Best For: Buyers seeking an entry point around $855,000-$868,000 who want a low-maintenance lifestyle and are comfortable with quarterly strata fees of $400-$1,000.

The primary benefit of a duplex in Sydney is affordability and potential rental income. With rental demand high in Sydney, you could earn around $1,000 per week from one unit. The main drawback is the proximity to your neighbour and potential for shared responsibilities.

• Getting into Sydney’s property market for less than the $1.49 million house median
• Having potential rental income of ~$1,000/week to offset your mortgage
• Owning a private yard and more living space than a condo
• Having fewer shared walls/neighbours than a townhouse complex
• No strata fees or body corporate costs if not strata titled

• Sharing a wall (and potentially hearing your neighbour)
• Needing to coordinate with a co-owner on shared maintenance (e.g., roof repairs)
• Potentially having a smaller yard/home than a detached house
• Having a smaller pool of potential buyers on resale compared to a standard house

Yes, duplexes appreciate in value similarly to single-family homes in the same area. As a rule in Sydney, properties with strata fees ranging from 0.4% to 0.5% per cent of the property’s value each year are considered reasonable. Duplexes are often cheaper upfront because the land and construction costs are split across two units.

When evaluating a duplex listing in Sydney, find the answers to these questions:

• Is there a Strata or HOA fee? Typically $500-$2,500 per quarter for apartments in Sydney
• What does it cover? (e.g., building insurance, common area maintenance)
• Property Insurance: Get a quote. Is it for the whole building or just your unit?
• Council Rates: Separate from strata, typically $1,500-$3,000 annually
• Emergency Fund: Plan for shared repairs (roof, foundation). Recommended savings: 1% of property value per year
• Rental Income Potential: Sydney median is around $1,000 per week

Consider areas like Campbelltown where you might get a block for $600,000 to $800,000, versus inner suburbs like Surry Hills or Newtown where land alone can cost over $1.5 million. St Marys in Sydney’s outer west recorded gains of 7.4% in the year to July 2025, showing strong growth potential in affordable areas.

A duplex is a single residential building with two separate homes on one lot, often under one title. The term “semi-detached” refers to the construction style (two houses sharing one common wall) but they are typically on two separate titles, meaning you own your side outright, including the land. In practice, the terms are often used interchangeably, but the legal title is the key difference.

Expect to pay between 0.3% to 0.7% of the purchase price annually in strata fees if your duplex is strata titled. For a $1 million duplex, that’s $3,000 to $7,000 per year. New strata buildings may have lower initial strata fees than older complexes due to fewer repair and maintenance costs.

Anecdotal evidence suggests fees increased 15 to 20% recently, driven by rising insurance premiums, the cost of materials, and stricter safety and maintenance standards. This makes it more important than ever to check the strata report carefully.

Always ask your real estate agent: “Is this property on one title or two?” This is the most important question. In Australia, a duplex on a single title may be subject to strata fees, while two semi-detached homes on separate titles will not be.

Look for terms like ‘Strata Title,’ ‘Torrens Title,’ or ‘Freehold’ in the property listing. These define the ownership structure and will significantly impact your ongoing costs and responsibilities.

Buying a duplex in Sydney can be an excellent entry point into the property market or a smart investment strategy, particularly when the median house price sits at $1.49 million. With potential rental income of around $1,000 per week and construction costs of $800,000-$1.4 million for a new build, duplexes offer a compelling value proposition.

The key is understanding exactly what you’re buying, from the title structure to the maintenance responsibilities. Use the checklists and real Sydney market values in this guide to evaluate each property systematically, and don’t hesitate to ask detailed questions about ownership structures and shared responsibilities.

Remember, in Sydney’s competitive market, the best property choice is the one that aligns with your lifestyle needs, financial situation, and long-term goals. Whether that’s a duplex offering rental income potential, a $1.49 million median-priced house for maximum privacy, or an $855,000 townhouse for low-maintenance living, armed with this information and current market data, you’re ready to make an informed decision.