Melbourne is a brilliant place to own a pool for about four months of the year. Without heating, most Melbourne pools only feel genuinely comfortable from late November through to March, and even then a cool change can drop the water temperature overnight. Add the right heating system and that window can stretch from September to May, which roughly doubles the use you get from a significant investment.
The question we hear most from clients is not whether to heat, but how. Here's our honest comparison of the three main options, plus the unglamorous accessory that matters more than any of them.
First, the physics
Every heating system is just a different way of putting energy into a very large volume of water. As a rule of thumb, raising 1,000 litres by 1°C takes about 1.16 kWh. A typical 40,000-litre pool going from 20°C to 28°C therefore needs well over 350 kWh before you even account for losses.
And losses are the real story. Most of a pool's heat escapes from the surface through evaporation, and Melbourne's wind accelerates it. That's why two identical pools with identical heaters can have wildly different bills: one is covered and sheltered, the other is exposed and uncovered.
Option 1: Heat pumps
A pool heat pump works like a reverse-cycle air conditioner. It pulls heat out of the surrounding air and transfers it into the water. For every unit of electricity it uses, a good inverter model delivers several units of heat.
Upfront cost: Typically around $4,500 to $9,500 for the unit, depending on pool size and model, plus installation. Many homes also need a dedicated electrical circuit, and some need a switchboard upgrade.
Running cost: This depends heavily on your pool size, target temperature, electricity tariff and, above all, whether you use a cover. As a guide, industry figures for a 40,000-litre pool held at 28°C through the shoulder season sit around $70 a month with a cover versus roughly $190 a month without one (at 30c/kWh with an inverter unit). Over a November-to-May season with consistent blanket use, an average 8 × 4 m Melbourne pool typically lands in the region of $400 to $800.
Pros:
- Works day and night, in cloud and rain
- Low running costs when paired with a cover
- Pairs beautifully with rooftop solar PV, so you can run it on your own daytime generation
- All-electric, which suits Victoria's direction away from gas
Cons:
- Heats slowly; plan to switch it on a few days ahead rather than on the morning of a party
- Less efficient in Melbourne's coldest months, so true winter swimming gets expensive
- Produces some fan noise, so placement matters (more on that below)
Best for: Most Melbourne families who want reliable swimming from spring to autumn.
Option 2: Solar pool heating
Solar pool heating pumps pool water through collectors on your roof, where the sun warms it before it returns to the pool. This is solar thermal, which is different from the solar PV panels that generate electricity.
Upfront cost: Varies with collector area, roof access and pipe runs. You need a decent area of north-facing (or east–west) roof, roughly proportional to your pool's surface area.
Running cost: Very low. You're only paying for the pump to circulate water through the collectors.
Pros:
- Cheapest system to run
- Long-lasting with minimal maintenance
- Great at gently lifting and holding temperature over a run of sunny days
Cons:
- In Melbourne, solar is largely ineffective from May to September, when days are short and cloudy
- Struggles through cool, windy or overcast stretches, which Melbourne springs are full of
- Needs suitable roof space, and heritage overlays or neighbourhood character controls in some Melbourne suburbs can complicate installation
- Collectors are visible on the roof, which some homeowners dislike
Best for: Owners with a good roof who mainly want to extend summer into October and April, or as a supplement to a heat pump.
Option 3: Gas heating
Gas heaters burn natural gas or LPG to heat water as it passes through.
Running cost: The most expensive of the three to run. Comparison figures commonly put gas at roughly $100 to $250 a month through a season, well above heat pumps and solar.
Pros:
- Heats quickly, regardless of weather
- Ideal for spas, where you want 38°C within an hour
Cons:
- Expensive to hold a pool at temperature day after day
- Victoria is steadily moving homes away from gas, and many new homes are built without a gas connection at all
Best for: Spas and occasional rapid top-ups, rather than as the primary heater for a pool.
The part everyone underestimates: the cover
If you remember one thing from this article, make it this: a heated pool without a cover is a very expensive way to warm the sky.
An uncovered pool loses a large share of its heat overnight, largely through evaporation. That means your heater spends the next day replacing heat it already paid for. A well-fitted thermal blanket slows that loss dramatically, and it's the single biggest factor in what you'll actually pay to heat.
The benefits go beyond heating:
- Water savings: Melbourne pools can lose over 1,000 litres a week to evaporation in warmer months
- Fewer chemicals: Less evaporation and less debris means less dosing
- Cleaner water: Leaves stay out of the pool
Covers range from a basic bubble blanket at around $200 to $2,000-plus for a heavy-duty cover on an automated roller. With heating in the picture, most pay for themselves within one or two seasons.
One honest note: covers only work if you use them. That's why we often recommend a roller system, or designing the pool from the outset for a concealed or automated cover. If it's a chore, it won't happen.
Side-by-side summary
| Heat pump | Solar thermal | Gas | |
|---|---|---|---|
| Running cost | Low to moderate | Very low | High |
| Heating speed | Slow and steady | Slow, weather dependent | Fast |
| Works in cloud and rain | Yes | Poorly | Yes |
| Melbourne winter | Possible, but costly | Largely ineffective | Possible, very costly |
| Best use | Primary pool heating | Supplement or summer extension | Spas and quick boosts |
Our recommendation for most Melbourne pools
For the majority of our clients, the sweet spot is an inverter heat pump paired with a quality thermal blanket. It gives reliable swimming from roughly September or October through to April or May, with running costs that are easy to live with. If you already have rooftop solar PV, the numbers get even better, because you can schedule the heat pump to run during the day on your own power.
If you have a good roof and want the lowest possible running costs, solar thermal can be added as a supplement. And if your design includes a spa, a small gas heater (or a heat pump sized for the spa) for quick warm-ups is worth considering.
Plan your heating at the design stage
Heating is far easier and cheaper to get right before the pool is built than to retrofit. When we design a Form. pool, we think about:
- Equipment location: Heat pumps need airflow and should sit away from bedroom windows, both yours and your neighbours'. Victoria's EPA residential noise rules restrict when equipment like pool pumps and heat pumps can be heard inside a neighbour's home at night, so placement matters.
- Electrical capacity: Confirming early whether your switchboard can handle the load, and allowing for a dedicated circuit.
- Pipework and future-proofing: Plumbing for solar collectors or a second heater now, even if you add them later.
- Cover integration: Planning coping, step and bench layouts so an automated or roller cover actually fits and works.
- Efficient pumps: A variable-speed pool pump cuts the cost of circulation, which every heating system relies on. Ask your installer whether it qualifies for a Victorian Energy Upgrades discount.
