Hot Tub Buying Advice

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 expensive hot tub shells are made out of either fibreglass or acrylic. Acrylic is 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.  Maintenance-free synthetic skirt are often a good buy since 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. 

The cover is crucial in providing adequate insulation.   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.

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Seating Arrangements and Comfort of the Hot Tub

A hot tub is meant to be relaxing and a hot tub that is not comfortable will not have the desired effect! The most important thing to remember is to get the right fit for you. 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.

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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 jets just blow air and create a pleasant bubbling or rippling effect in the tub, but these jets don't actually provide a therapeutic massage. Some jets just force out water, but the ones you want for a proper massage 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, using a diverter, will make the pressure from the remaining spa jets stronger for a more forceful massage.  You can often interchange the positions of the different types of massage jet.

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.

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Heaters and Energy Efficiency

Your hot tubs operating cost will be determined, primarily, by its ability to retain heat. Virtually every self-contained hot tub is designed to maintain a constant temperature, with the heater turning on automatically as needed. Hot tubs that perform best at preventing heat from escaping will cost the least to operate. 

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. the cover should seal 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.

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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 hot tub will produce just as much jet power as a higher horsepower pump in an inefficient tub, 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.

Usually the pumps have two speed settings, one for massage and one to provide a more gentle flow and power thr filtration system.  Some hot tubs are also fitted with 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.

In hot tubs with just a single speed pump and no separate circulation pump 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 and a pump running at full speed can be noisy. If your neighbours are close it might be a good idea to consider 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!

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Hot Tub Filters

Hot tub 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 filters last longer when they are allowed to dry out between cleanings.  If you rotate your filters in this way and clean them properly they should last at least 12 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 hot tub 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 hot tub companies frequently go out of business and you need to be sure that you can locate an alternative source of filters.

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Ozone and Chemicals

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

Many hot tubs come with ozone generators that help to remove both bacteria and any viruses in the water and reduce the amount of chemical disinfectants needed.  This is good because ozone does not irritate the eyes and skin like the chemicals can, but be aware that the ozone generator will only work whilst the water is circulating and can never be 100% effective.. 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 big 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.  You must always use chemical water sanitation to back them up.

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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. They sound like a good idea but unfortunately they tend not to produce a very strong scent and are inevitably dissapointing. There are many proprietary products on the market now that contain natural salt and very small quantities of pure essential oils which are perfectly safe to use in your spa water and much nore effective at producing a nice smell, the essential oil also has real therapeutic qualities.

It's generally not a good idea to use liquid scent products in a hot tub as they can compromise the water quality.

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Additional Features such as Lights, 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. However, be aware that if anything is likely to fail, it's the audio visual system and not the hot tub electronics.

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All the spa components should be fully tested and backed by a manufacturer's warranty. You can always 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, that some hot tub warranties are PARTS ONLY and that if something does go wrong with you tub within the warranty period you could still be left with a big labour bill.

Also, remember that the warranty is worth little if the manufacturer is not around to back it up so make sure that you buy from a reputable, established company.

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Hot Tub Safety Considerations

If small children are likely to me near you hot tub then make sure the cover comes with a means of locking it securely. 

Use a qualified electrician to connect the electrical service to the hot tub and, when using a 13 Amp hot tub connected to a standard domestic electrical supply, always ensure that an RCD is fitted.

Make sure that you have a good light so that you can see where you are stepping when you get in and out at night. 

Be sure to heed the warnings about restricted hot tub use by small children, pregnant women, people with certain health conditions and people under the influence of alcohol or drugs.

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