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What is a plunge pool? | HotSpring Spas

What is a plunge pool?

Plunge pools are becoming an increasingly popular addition to Kiwi homes. These small pools of cool water offer you a quick and refreshing dip, perfect for cooling off in the heat of summer or cooling down post-exercise.

But while a traditional in-ground plunge pool might be a luxurious home amenity, it’s also one that is limited in functionality… until now.

Welcome to the evolution of the plunge pool. A Hot Spring spa pool fitted with a CoolZone System doesn’t just offer all the health, wellness and lifestyle perks of your very own in-ground pool – it delivers so much more.


What is a plunge pool?

The term ‘plunge pool’ is used to describe a number of things. Plunge pools are small yet deep pools of water that can form naturally, usually at the base of waterfalls where they’re carved into rock and earth over millennia. In more recent times these natural pools have served as inspiration for the manmade plunge pools now found in many backyards.

Artificial plunge pools are small pools of water, usually measuring just a couple of metres long, wide and deep, that look to recreate the refreshing dip found in the naturally occurring equivalent. A lack of heater leaves the water cool – though sometimes a little too cool – all year round.

In recent times a third form of plunge pool has emerged – one designed to offer all the refreshment of the first two, but add generous helpings of luxury, warmth and functionality to the mix. A Hot Spring spa pool fitted with a CoolZone System is able to cool itself to 15C… then warm itself back up to 40C, while offering relaxation and revitalisation from luxurious hydromassage jets!

What size is a plunge pool?

A traditional in-ground plunge pool is a compact version of an unheated swimming pool. They generally measure 2-5m long, 2-3.5m wide and an average of 1.2m deep, although some plunge pools can be far deeper. Despite these apparently compact measurements, plunge pools do demand plenty of space if they are to comfortably fit in a backyard due to fencing and walking room considerations.

By their nature plunge pools are too small to swim in; if a pool is larger than these dimensions it begins to be considered a lap pool. Some plunge pools also encroach on the territory of an in-ground spa, featuring seats and jets.

The Hot Spring version of a plunge pool, meanwhile – a spa pool fitted with a CoolZone system – is a perfectly compact affair. The CoolZone system can be added to the majority of our Limelight and Highlife spa pools, the largest of which measures just 231 x 280 x 97cm. These portable spa pools demand far less space, as they can be placed in corners, on decks and wherever else you might have a small amount of spare room.

What is the cost of a plunge pool?

Featuring cutting edge technology delivered in a beautiful and compact package, a Hot Spring spa pool fitted with a CoolZone system is like a plunge pool, a spa bath and a day spa rolled into one. Featuring expertly designed and strategically placed hydromassage jets, automated water care technologies and the most efficient machinery on the market (with running costs as low as $1 a day), these truly are feature-packed machines.

The cost of all this innovation? Your investment in a Hot Spring spa pool will generally be lower than the investment needed to install a traditional plunge pool, while delivering so much more. The smaller body of water is also less costly to fill, heat and maintain.


Plunge pools vs spa pools

Which should you choose: an in-ground plunge pool or an above-ground, CoolZone-fitted spa pool? As word has spread about Hot Spring’s CoolZone technology, more and more Kiwis are recognising the enhanced capability and value for money that a portable spa pool can deliver over an in-ground plunge pool.



An in-ground plunge pool is simply a pool of cool water – nothing more, nothing less. A Hot Spring spa pool fitted with a CoolZone System can be exactly the same… but it can also be a place to rest and relax, a romantic escape, a massage therapist, a party host and more. With the option of heated water, hydromassage jets, interior and exterior lighting, water features and complete audio-visual systems, the functionality of a Hot Spring spa pool is seemingly endless compared to that of a traditional plunge pool.

Health benefits

Jumping into the cool waters of a plunge pool offers a host of scientifically proven health benefits, including reduced pain and inflammation, better sleep and improved mood. But add heated water and hydromassage jets into the mix, and the health and wellness benefits grow exponentially – spa pools offer an effective way to manage a wealth of conditions, such as arthritis, migraines, fibromyalgia, chronic pain and anxiety. The CoolZone System also grants the opportunity to capitalise on contrast bath therapies!


In-ground plunge pools can be costly and time-consuming to install. Between inspection, design, excavation, construction, filling and treating, the installation of a plunge pool can take a month or more from start to finish. Hot Spring spa pools, meanwhile, are designed as compact, self-contained units. As long as you ensure you have enough space, installation is a breeze. This also means a Hot Spring spa is portable – if you want to move your spa to a different spot in your backyard, or if you are moving house and want to take it with you, you can!


It’s simple maths: more water = more maintenance. Because they are usually bigger, plunge pools require more chemicals and more time to keep clean and clear, and they often lack innovative water management systems. You’ll also spend more money filling and heating an in-ground version. Hot Spring spa pools, meanwhile, bring a wealth of automated water care technologies, like the FreshWater Salt System. They demand just a few minutes a week to keep the H2O clean, clear, soft and fresh.

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