How to Buy a Hot Tub

How to CHOOSE a Hot Tub

Apart from the obvious issue of the price there are numerous factors to consider when purchasing a spa.

Unfortunately for the spa shopper no-one in the UK has actually tested and compared hot tubs for the purpose of helping the consumer make an informed choice. There are some US consumer guides available, but on the whole these are not directly relevant to the UK because the specifications and prices of the spas produced for export are usually quite different to those models sold in the country of origin.

Below is a list of some of the factors that you should consider when making your purchase.

Size and Location of the Hot Tub

Hot Tub Construction.

Seating Arrangements and Comfort

Hot Tub Massage Jets

Hot Tub Heaters and Energy Efficiency

Hot Tub Pumps and Diverters.

Hot Tub, Filters

Ozone and Chemicals.

Additional Features such as Lights, Aromatherapy, Waterfalls and Entertainment Systems

Warranty

Hot Tub Safety Considerations

Also have a look at our list of frequently asked questions

Size and Location of the Hot Tub

The size of spa you look for will be affected by both the space you have available and how many people you would like your hot tub to hold.

Before you begin shopping, decide where you would like to put your tub. It's a good idea to outline the hot tub's proposed location using a garden hose or rope. This will help you visualise your plan for the area. Also consider the following factors:

the tub must be placed on a solid, level, self draining surface. Bear in mind that a full tub with four or more people inside can easily weigh 3 tonnes. If the tub is placed on a concrete pad it should be at least 4" thick.
if you decide to place the tub on wooden decking the it must be sturdy enough to support the weight. Also, bear in mind that any noise from the spa will be increased if the deck is able to vibrate. An alternative solution could be to mount the tub on a solid base and build the deck around it.
you will need easy access from your changing area to and from the tub. If you intend to use the tub in cold weather (the best time to use a tub!) then it's probably a good idea not to place it too far from your house.
overhanging trees can drop unwanted debris into the tub and also cause unwanted shade.
bear in mind that grass and debris from the users' feet will get transferred into the tub so a clean path from the changing area to the tub is a good idea.
you will probably prefer a sheltered spot that isn't overly exposed to strong winds, but a good view will enhance the spa experience.
consider how much privacy you would be comfortable with.
consider how easy it will be to fill the hot tub, using a garden hose, and also to empty the tub. Most good quality tubs have a bottom drain that you can attach a hose to, but you might prefer to be able to direct the water into a drain rather than over your garden.
unless your spa has very low sides, you will need to make or buy a set of steps to get in and out.
for safety, it is best to have your tub wired directly into a waterproof, externally mounted, earthed and fused supply. This should be a dedicated circuit with no other appliances sharing the power. 13Amp tubs may be connected via a standard waterproof external socket, but an RCD should always be used.
don't forget that you will need to allow for access to the equipment compartment for service and that extra space around the perimeter will be needed if you intend to fit a cover lift.

Construction of the Hot Tub

The standard of construction and quality of the materials used to build the hot tub will obviously determine how long you will be able to enjoy your investment. Look carefully at the fit and finish of the hot tub, if the superficial things look tacky there is a good chance that the things you can't see are tacky too.

Most hot tub liners are made out of either fibreglass or acrylic. Acrylic is by far the better material because it is moulded in one piece, it is lighter, more scratch and wear resistant and will not deteriorate with age. An acrylic spa will therefore have a longer life than a fibreglass one. The type of skirting is also important. A hardwood such as mahogany will provide the most durable wooden skirting, but it will still need treating with a wood oil once a year. If you are building your spa into decking or putting it somewhere with restricted access a maintenance free synthetic skirt could be a good buy and many now look very much like real wood.

It is also important that you search for a proper method of insulation Many good quality spas are filled with polyurethane foam which conserves heat and also supports the spa plumbing. Usually a high density heat resistant foam surrounds the equipment bay, lighter foam insulates elsewhere. While this process adds to the cost of manufacturing, research has shown that full foam insulation provides substantial savings in running costs. Alternatively fibreglass wadding can be used, which is a less expensive alternative.

You should also consider the cover, which is crucial in providing adequate insulation, and the cover removal systems available. Most covers consist of two slabs of polystyrene foam encased in vinyl. The vinyl will need cleaning periodically with mild soap and water and occasionally treated with a vinyl conditioner. Make sure that one person can easily remove and replace the cover without help. There are a range of cover lifting devices available to make this easier.

Finally, look for controls that are user-friendly, easy to operate and adjust. On the top-end hot tubs many electronic functions can be operated via a waterproof remote control unit.

Seating Arrangements and Comfort of the Hot Tub

A hot tub is meant to be relaxing. A hot tub that is not comfortable will not have the desired effect. There are several different seating arrangements offered in most hot tubs and the most important thing to remember is to get the right fit for you. Good dealers will allow you to try out ('wet test') a filled hot tub in the showroom, but if you don't want to do this you can at least sit in an empty tub to ensure that the tub is comfortable. Here are some other things to consider:

are you able to move around the tub easily?
is the foot well spacious enough for everyone's feet and legs?
is there lumbar support for your back and can the person in each seat remain comfortably seated when the jets are turned on? In the buoyancy of water, it doesn't take much pressure to move a person around and so the pressure from the pumps should be controllable.
note the depth of the seats in relation to the water level and consider whether everyone in your family will be able to enjoy the hot tub without struggling to keep their chins above the water? Many hot tubs offer seats of varying depths.
if the hot tub has a lounger, is it comfortable? Be wary of a lounger in which the backrest is too horizontal—with the buoyancy experienced in water, you'll find it very uncomfortable trying to resist floating, especially when you turn on the hot tub jets.
are the headrests comfortable?

Hot Tub Massage Jets

The ideal number and type of jets is very subjective. Some people wouldn't consider a hot tub that didn't provide lots of powerful massage while others are satisfied with very little water movement as they relax in the hot water. Consequently you will need to look for the combination of jets that feel best on your body and matches your budget.

The quality of the massage you receive from your hot tub is dependent much more on the type of jets and their placement than simply the number of jets. As you look at hot tubs you'll find a wide variety of different jets.

Some just blow air, some just force out water, but the ones you want for a proper massage effect are jets that mix air with pressurized water. Good quality tubs will enable you to customise the massage by regulating the amount of air and/or water supplied to either individual jets or groups of jets. Often restricting or turning off the water flow to some of the spa jets will make the pressure from the remaining spa jets stronger for a more forceful massage. You can often also interchange the positions of the different types of jet. Jet Placement is a critical point that many spa shoppers neglect until it's too late. When you are sitting comfortably in each seat, the jet stream(s) should impact your body's major muscle groups, not your bones. Make sure the spa of your choice has jets that can be positioned to massage the area(s) where your muscles are typically the most tense or fatigued.

Many spas and hot tubs also feature a blower that produces air bubbles from fittings throughout the spa to gently caress the body. While it is certainly not an essential feature, many people enjoy the sensation.

Hot Tub Heaters and Energy Efficiency

Your spa's operating cost will be determined, primarily, by its ability to retain heat. Virtually every self-contained spa is designed to maintain a constant temperature, with the heater turning on automatically as needed. Spas that perform best at preventing heat from escaping will cost the least to operate. Spas that have their pumps, heaters and other electrical equipment contained within the spa shell, rather than in a separate external unit, will also generally have better thermal efficiency.

Because heat rises, the most important factor in trapping heat is the spa cover. Most consist of two slabs of polystyrene foam encased in vinyl. Check to make sure the cover seals uniformly against the top rim of the spa and at the place where the two halves come together. You should also ensure that the spa features effective insulation for the shell and plumbing. The less chance there is for cold air to cool your water, the lower your electricity bill will be.

Hot Tub Pumps and Diverters

Hot tubs come equipped with one, two, three or occasionally even four separate pumps. In simple terms the more powerful the pumps, the more powerful the massage, but efficient plumbing, better jets and flow control are as least as important as the power of the pump. A lower horsepower pump in a more efficient spa will produce just as much jet power as a higher horsepower pump in an inefficient spa, and less noise too.

Where there is more than one pump, each pump is usually used to power the jets in a particular area of the tub. Therefore, by turning one pump off in a multi-pump system you can turn the jets off to one or more of the therapy seats. Sometimes, instead of providing more than one pump, some manufacturers install a diverter that diverts the flow from one side of the tub to the other. This is obviously a lower cost option, but it does mean that you won't be able to use all of therapy seats at the same time.

Some times the pumps have two speed settings, one for massage and one to provide a more gentle flow. Some hot tubs feature small circulation pumps that continuously filter the water and provide the flow needed for the heater to maintain the set temperature and the ozonator to work. Hot tubs without circulation pumps rely on the low speed of a two-speed pump turning on periodically to do the same job. On these hot tubs, this periodic operation is typically controlled by a built-in programmable timer or by the hot tub's thermostat.

It is best to avoid hot tubs with just a single speed pump and no separate circulation pump because the pump will need to be on full speed for at least 4 hours a day to provide the filtration needed to keep the water clean. This will be both noisy and hard on your electricity bill.

You should listen to how loud the hot tub is with all pumps turned on. A loud spa will not only inhibit relaxation, it will also alert your neighbours each time you take a dip!

Hot Tub Filters

The filters are designed to be cleaned and reused a number of times before replacing. It is important to check to see how easy it is to remove and replace the filter and to remember that smaller filters need to be cleaned more frequently. It is a good idea to keep a spare set of filters and to rotate them in your tub because they last longer when they are allowed to dry out between cleanings. If you rotate your filters in this way they should last 12 - 18 months before they need replacing.

It is imperative that you ensure that there is a reliable source of spare filters available before you buy a hot tub. It might not seem very important initially, but if you can't get hold of replacement filters you won't be able to use your spa for very long. Many hot tubs made in China use unconventional filter sizes that are only available from the Chinese manufacturer, rather than the standard filter sizes used by US and UK hot tub manufacturers. Beware that companies selling Chinese made hot tubs frequently go out of business and you need to be sure that you can locate an alternative source of filters.

Ozone and Chemicals

You will need to use chemicals and other additives to keep the water disinfected (sanitized) and chemically balanced.

Many good quality hot tubs come with ozone generators that help to remove both bacteria and any viruses in the water and vastly reduce the amount of chemical disinfectants needed. This is good, both from a cost point of view, and also because ozone does not irritate the eyes and skin like the chemicals can. Corona Discharge (CD) ozone generators, although more expensive than ultraviolet (UV) ozone generators, yield higher concentrations of ozone for greater effectiveness and are less costly to maintain.

The problem with Ozone generators is that it is very hard to tell if they are working correctly, or indeed if they are working at all. Therefore you can never completely rely on them and you must always use chemical water sanitation to back them up.

Additional Features such as Lights, Aromatherapy, Waterfalls and Entertainment Systems

You will spend a lot of time in your hot tub just relaxing, rather than enjoying the full force of the massage jets. It is therefore worth considering the 'atmospherics'. For example, factors such as whether the spa includes a tranquil water feature such as a whirlpool jet or waterfall, the underwater lighting (which may be coloured or multi-coloured) and the quality of any audio visual system can all make a difference to how much use you make of the spa and therefore how much value-for-money you are getting with your purchase.

If you are interested in aromatherapy then many spas have built in systems to blow scented air through water. These systems pass the air over beads impregnated with aromatherapy oil before it enters the tub though the jets. However, they tend not to produce a very strong scent and there are also many proprietary products on the market now that contain pure essential oils and are perfectly safe to use in your spa water.

Hot Tub Warranties

All the spa components should be fully tested and backed by a manufacturer's warranty. Ask for a copy of the warranty and read it thoroughly before you buy. Make sure that you understand which spa parts are covered under warranty and for how long. Be aware, however, that the warranty is worth little if the manufacturer is not around to back it up.

Hot Tub Safety Considerations

Make sure the spa cover comes with a means of locking it securely to the spa to prevent unauthorized use. Use a qualified electrician to connect the electrical service to the spa and make sure that you have a decent light so that you can see where you are stepping when you get in and out at night. After you get your hot tub, be sure to heed the warnings about use by small children, pregnant women, people with certain health conditions and people under the influence of alcohol or drugs.