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Can you Heat the Pool and Spa at the Same Time?

A pool and spa combination is the ultimate addition to your backyard and the promise of either rigorous exercise to invigorate and tone your body or a relaxing water treatment at the mercy of powerful heated water jets is nothing short of a supreme experience to enjoy in the comfort of your home.

In the interest of clarity, the words pool and spa can have confusing connotations and in this context, they can refer to structures or ‘modes’. 

When referring to physical structures here, a pool is an artificially constructed body of water for recreational activity mostly swimming while a spa is a body of water in which recreational water treatment is the main goal. Essentially, spas are a type of pool.

When referring to modes, you will have pool mode and spa mode. Pool mode is basically where the water in the pol or spa is stationary and at standard ambient temperatures while spa mode is effected to activate jets, heating, and bubblers to engage in water treatment and massage.

Pools and spas can be in three modes where they can be the same structure, two separate but connected structures, or two separate and independently operated structures. Each of these requires different mechanisms for heating.

Can you heat the pool and the spa at the same time?

Spa-pool Option

This is a combination of the pool and spa in which case there are some spa-pools types that fit in this category such as the hot tub and above-ground portable pools. There are inground spa pools but they are not a common feature since inground pool construction is expensive and there is hardly any need for a small structure in such cases.

Most inground pools are large and deep. These spa-pools are typically small in size and are operated using a single control unit that houses heating options, water treatment and filtration mechanisms, air blowers, and a hard water system all in one unit attached to the tub.

For the spa-pool, heating the pool and spa is basically heating the same thing provided you have the right settings. 

Pool heating options typically do not go beyond 80 degrees Fahrenheit while spa heating can be as high as 100 degrees Fahrenheit which is quite good and toasty for a warm spa treatment. The difference between heating the pool and the spa here is just in the settings and temperature levels.

Separate and independent pool and spa

These are fairly straightforward operationally and since they have separate controls and management units, their heating systems are also separate.

This type of pool can either be in-ground or above ground with the former often being the case such as with pubic pools. Heating levels rarely go beyond a warm 84 degrees Fahrenheit. 

A stand-alone spa can be an indoor pool, a hot tub, or an outdoor pool that’s above ground or inground. They are typically smaller with the largest ones being up to 10 feet in length but this is rare due to the cost of heating this much water only for the indulgence of one or two persons at a time.

They are, however, the epitome of luxury.

Spa heating can accommodate temperatures of up to 120 degrees Fahrenheit with higher temperatures deemed too dangerous and unnecessary for the enjoyment of a water treatment anyway.

Separate but connected pool and spa

This combination is the most common and most convenient pool-spa construction. The pool is usually in-ground or off ground meaning its body is halfway raised above ground level.


The pool is usually large and is ideally constructed for recreational or professional swimming activities.

The spa is a separate structure that is smaller in size located adjacent to the pool or completely within the larger pool such that they share water. Most people assume the spa to be a kiddy pool due to its smaller size and shallow base. 

Many even utilize it this way which is quite in order and allows adults some freedom in the larger pool while keeping an eye on their small children.

The pool and spa in this case can be heated at the same time which allows you to take a decent rigorous swim in the pool and then massage away the fatigue in the spa afterward.

The pool and spa have a shared heating system. When you want to heat the pool, the spa behaves just like an idle pool and the water in it acquires the temperature of the pool water, normally around 80 degrees Fahrenheit. 

This is because when the settings are in ‘pool mode’ the valve system cycles water to both the pool and the spa since the spa under these settings is just part of the pool.

When you want to heat the spa, you will have to turn your settings to spa mode which in turn initiates a different valve function. 

In spa mode, the valves only cycle water into and out of the spa where heating can then impact only the water in the spa, heating the smaller amount of water quite fast from 84 degrees Fahrenheit to maximum temperatures of about 104 degrees Fahrenheit.

This type of shared pool is by far the most convenient for you since it offers you the benefits of both the large pool and the treatment benefits of the spa within. Having one management unit is also energy efficient and maintaining the control unit is fairly easier.

This pool-spa combo is also the best to have in winter since its construction can withstand the rigors of wintertime and heating it for a swim or a soak is easy. If anything, unlike the portable hot tub which cannot be used during winter, this kind of pool can be used all year round. 

In the winter, heating can be adjusted to accommodate external temperatures, and semi-permanent or temporary housing can be placed to turn it into an indoor pool allowing you to enjoy a warm swim during the months when such a soak is most coveted.