Cottage Hot Tubs

hot tub(All safety, technical and other requirements should be checked with qualified people.  This information is provided only as initial guidance  to take some of the uncertainty out of deciding if buying a hot tub a choice you wish to make.  Make certain to ask tub suppliers for all their advice and any appropriate written materials.  Make certain to check the information below before acting on it).

Historically, hot tubs were wooden tubs.  In the late 1960s, tubs were improved by making them out of moulded fiberglass of thermoplastic with the addition of jets.  At that stage, ‘Spa’ was used to mark the advance and difference from old style tubs.  Since then, the words have become interchangeable although it is possible to have a bath fitted with jets and it described as a Spa.

They gained fashionability with Scandinavian influence and, latterly, from the USA.  As with wood burners, they offer an extra that the majority of people do not have at home making stays a little more special.


Cottage hot tubs will call for more management, cause costs and can be quite expensive to buy and install.  The aim of this advice is to lay out some of the pros and cons and provide some useful information about their use and management, once installed.

Is it worth buying a hot tub?

In the current market certain holiday lets do well offering a hot tub as an extra.  There is an element of fashion to this so it is worth taking care before going ahead, however this trend could last for a long time even after the fashionable element has fallen away.  It is possible that the UK will take to them on a more permanent basis as they exist in other European countries.

The way the market responds and the economics varies depending on the number a holiday let sleeps. There is no harm buying on line as long as you are fully clued up on what you are buying.  It is a good idea to see tubs in operation before selecting and, if possible, speak to their owners. Warranties are important but check them carefully for exclusion clauses and stipulations and try to find out how and if they are, in turn, guaranteed.

As with any extra, it has to pay its way.  Smaller holiday cottages may find that the costs of purchase, installation and running do not get an adequate return in the form of more bookings and, possibly, higher rates.  As the numbers that can sleep in a let rise, so the economics of providing a hot tub turn more positive.  Sleep six and they can be positive, sleep 8 and above and it is common that they turn out a useful and profitable addition.  There is some argument that, above sleep 16, their advantages are less significant.

Although hot tubs come in differing sizes, the added value they provide for larger lets is substantially higher than for smaller ones.  Comparing, say, a sleep 2 with a sleep 8 or above the use made of a hot tub (and the added value it offers)  is radically more for the larger let.  Although this general rule applies, there can be exceptions.  If you can get sufficient extra bookings or manage to raise rates sufficiently, extras will pay.  Increased bookings and occupancy rather than higher rates will make the greatest contribution.  Nowadays, it is even worth checking if there is an IPod docking station and an MP3 Player.

Buying well is important.  Numbers and heights of users need to be considered.  You need to provide a useful private location for the hot tub close to the accommodation with either decking or some friendly surface around the tub extending to the accommodation.  Drainage and a water supply are important as is an electric supply.  Running hot tubs can be expensive in terms of time and chemicals have to be purchased.  It is a good idea to drain and refill for every stay; not least, to minimise any health risks some owners say this is the most economical way of operating.  It is worth calculating the cost of the water, additional electric costs to get a clear view of the economics.  Your time should be considered in this calculation.

Hot tubs can be difficult and, sometimes, impossible to repair so buying quality and maintaining well is important.

Another factor is energy consumption.  There’s no point in having too many water jets that will not be able to operate at maximum potential because the power is not available instead of a smaller number, capable of full blast on the available current.  Jets should be adjustable and able to be turned on and off.  The lure of many jets for little money can be, at best, a false economy and, at worst, a bad buy.  13 amp sockets can only supply so much electric power.  You should also check the availability of spare parts before buying, especially the most commonly needed components and those most frequently needed buy but not so easy to find.  This may sound over cautious, but a little care can avoid immense upset or worse later on.

There are many suppliers of hot tubs and prices vary considerably so it is well worthwhile shopping around and getting several quotes.  Managed well for holiday lets that sleep 8 or more, in the current market (January 2014) they are often a very useful and effective addition to a holiday let business.  There is some argument that they are not so profitable for very large lets.  Do not be tempted to buy one to share between cottages, in general, this is not a good idea.


Jets in tubs are an often appreciated extra and it is worth considering this when purchasing.  There are two types: air and water.  The water will offer a better quality of experience (hydrotheraputic) where air jets are more cosmetic.  But combined, the result can be superior.

A leading brand of hot tub offers high quality hydrotherapy and sophisticated controls with a combination of air and water jets.  Its seats are carefully designed with posture and comfort in mind… this is all about soothings aches in bones and tension in the back and shoulders as well as addressing stress and strain.  When buying a hot tub, it is important to gauge what you want before buying.  Getting the right product that adds value in the best way is, of course, the aim.




hot tubs

In most cases, planning permission is not required but in areas of outstanding national beauty or conservation areas it can be an idea to check with local planners.  Try to locate in a private spot that is not overlooked where there is good access for sunlight but, ideally, sheltered from wind.  You need to arrange things so that garden life cannot find its way into the water.

You will need a solid, level platform, an electric supply and the ability to use a hose to fill it up.  When designing the base, make sure that there will be accommodation for any servicing or component access doors in the hot tube.  Installation characteristics vary depending on the design of the tub.  It is also important when designing the base to consider the final surface you will provide, drainage and such mundane things as fixings for a fence or rail to run around the hot tub area.  Getting the foundations right for the platform is important. If the base is not flat, tubs can crack.  Using a cover that is too heavy or does not fit well can cause damage.  If you see a small crack, its progress can be halted, assuming the cause is detected, by drilling a 3-5mm hole at the end of the crack.  Then use fiberglass behind the crack, sometimes you can buy acrylic pellets.  Combine them with acetone and fill the hole.  However, if in doubt, check with someone in the business.

Repairing covers can be involved especially without a heavy duty sewing machine and other specialist bits of kit such as the right type of vinyl and a way to heat seal polystyrene internal covers.  The average life of a cover is not more than 5 years and it is usually advisable to buy from off the shelf rather than try to do DIY.

Spas can quite heavy, even when empty, with 250 kg being not uncommon.  (About 500 lb or .25 of a tonne)  Moving them around could call for small trailers or dollies.  The usual method is to put it on its side ensuring the pump side does not take the weight.  They tend not to fit easily into small box vans or transits  so you may need  a small flat bed truck for transport.


Generally, tubs can take about half a day to heat to body temperature but size and time of year are relevant.  Thermostats are used to control temperature.  The electricity used varies but 15 kw per day is a guide.  Costs are reduced with good insulation and covers.  You can use a 16 to 30 amp fused electric socket for the electric supply in many cases.  Running costs (2014) can be around £1 per day.  Their unfilled weight can be around 250 kg.  Cleaning costs can come in at around £5 per month before labour and you do not normally need to install plumbing beyond the provision of a garden hose or similar to fill them up coupled with drain off provision.

Some recommend that tubs be drained and cleaned every three of four months.  There is some debate and some owners find the economics of chemicals and maintenance of water quality can point towards draining and refilling for every stay in favour of keeping the same water for any prolonged period.  Electrical installation should be done by a qualified electrician especially as there is going to be quite a bit of water near-by.

Electric consumption varies from 1 KW to 6 KW and is related to water volume, the ambient temperature and to refilling practices.

For a 300 gallon (1360 Litre) tub running at 1.5 KW in the summer it can take about 20 hours to get up to temperature.  Many choose to keep the heat on all the time.  In this case, the hot tub will raise temperature by about 3c per hour.  Turn off the heat and it can lose temperature by about 2c per hour which means it will take about 40 minutes to get back up to heat.   So it is not necessarily a disaster if the electricity goes off for a hour or two.

Running costs vary from around £5 per week to £30 a week.  This depends on several factors:  how it is covered (bespoke thermal cover, moderate quality cover or just floating bubblewrap); how well the body of the tub is insulated; if an air blower is used, it will cost more to heat.  A good quality 1360l  (300 gal) tu,b used about 30 minutes a day, assuming 15p per Kw, should cost about £260 in electric annually depending on climate and local energy costs.

The economics of keeping a spa switched on, or intermittently, depend on how often it is to be used, how well it is insulated and the local climate.  If it is to be switched off for any prolonged period or in a climate where freezing is a possiblity, make sure it is drained.  A 300 gallon tub using an average hose can take about 1.5 top 2 hours to fill.

Preferred temperatures of the water tend to be about body temperature and a little higher at 40c in Winter however women tend to prefer higher temperatures than men.  Why, is beyond me.  A thermometer is an excellent buy taking all guesswork out of running a spa whilst ensuring you do not spend excessively keeping the water too warm.  Good quality spas have these built in with display readings.

To empty a tube use the bottom drain.  If there is no drain you can either use a submersible pump or rig up a simple syphon with a length of hose pipe.  (Run the hose and, when it is full, stop up both ends.  Immerse one end in the tub water ensuring the other end is below the bottom of the tub.  Then, unstop the submersed end followed by the other end.  The weight of the descending water should pull water in the hose out of the tub, over the rim and down to drain away at a lower level.  It can take a bit of trial and error getting the technique right.

Airlocks can sometimes stop pumps from working.  A blast from the hose through the pump from the filters can usually blow the airlock out.

It is worth finding out about the reset or thermostat safety switch.  It operates when a problem with the heater is detected and is a an essential safety device.

Maintenance / Cleaning

  • Annual maintenance should include a system clean sort out lime scale and biological deposits from the pipe system.  This is often done by adding system cleaner to tub water refilling and circulating it for a hour or before draining it off.  Then, rinse the system with a clean fill and refill again for further use.  During this process, the filters should be removed and soaked in cleaner and blasted with water before returning to the tub.
  • Filter cleaning is to remove dirt and grease.  Soak for 24 hours in cartridge cleaner to break down grease then do the water blast.  Hard water areas may call for a more intense blast of water to remove lime scale.  It can be an idea to clean cartridges every month or less using shorter treatments to keep on top of the problem.
  • It is important to check ozone generators; they can appear to be working when they are not.  This is a safety issue.
  • Weekly: you should use Non Chlorine Shock or Calcium hypochlorite.  Clean the filter and rotate usage of the filter with another.  Check water balance and act accordingly to correct.
  • Monthly: use lime scale remover in hard water areas.
  • Every 6-8 weeks: clean cover with weak chlorine solution.  Replace filters every 6-10 months
  • Change water (If you do not habitually drain between stays or over shorter periods)

Another check list worth considering

Each day

Check clarity of water; that automatic dosing systems including ozone systems, are working; chemical reserves in resevoirs and the pH value concentration of residual disinfectant

During the day

Dosing systems (inc ozone); pH and residual disinfectant; Check total dissolved solids (TDS) where applicable

End of day

Check to clean overflows, grills and waterline; ditto tub pool and surround; backwash sand filter; check strainers and take out all bits and pieces;

Record users and make sure any exceptional events are recorded

When you refill

Totally drain not forgetting the blance tank; clean fliters and strainers; check water balance


Microbiology checks for organisms; can opt for complete chemical test;  check and clean pipework and jets for biofilm where you can; clean air filters if present; check breakers and any earth leakage safety devices; test automatic systems such as timers, cut-outs etc:; clean electrode and check calib or any pH or disinfectant controller

Three monthly

Check for Legionella;  clean and disinfect airlines where practical; take a close look at sand filters and any diatomaceous earth filter membranes


Review written processes and procedures; check that sand filters are working correctly


  • Water hardness is the level of lime in the water.  Lime scale control is important using the appropriate chemicals to ‘soften the water’.
  • pH levels need to be kept fairly neutral to avoid corrosive water and damage to equipment
  • Chlorine or Bromine can be used to control bacteria.  Bromine is often carried in tablets.  Ideal level is between 3 and 6 mg/l
  • Chlorine can do much the same as Bromine at concentrations between 3 and 5 mg/l
  • Non Chlorine Shock deals with odours, sweat, body oils and washed off cosmetics
  • Ozone systems are a major help in combating bacteria.  When fitted Bromine or Chlorine effectively mop up after the work done by the Ozone.  Bromine treatment tends to be more robust when pH levels vary and has the additional attraction of appearing to be less toxic than Chlorine but Bromine can be accompanied by water clarity concerns.


hot tubsGuest use of  hot tubs in holiday lets is often best arranged on a non-contractual basis.  I.E.  The rent charged specifically excludes use of the hot tub which can be made available, free of charge, on request.  This avoids any problems that can arise if the weather makes use unattractive, if the hot tub breaks down or for any other reason.  Surfaces around the hot tub should be non-slip and guidance / instructions should be laid out in the welcome and information book that should be read by all party leaders on arrival for transmission to all guests.

Guidance and instructions

A few suggestions are worth considering are below:

  • Guests should shower before using the spa
  • The spa is not a bath and so no soap or shampoo should be used
  • No pets of any description should be permitted near or in the spa.  The temperature will terrify them and spas are not to be used to clean animals.
  • Small children and babies should not use the spa.
  • All guests under the age of 16 should be accompanied by an adult when using a hot tub.
  • The cover of the tub should be treated with respect and replaced after use.
  • Any faults or problems with the hot tub should be reported to the owners or the representative as soon as practical so they can be mended to ensure, where possible, that the spa will be available for the most time possible during a stay.
  • There should be no running in the spa area.
  • No glass should be used in proximity to or whilst in the spa; the plastic glasses and containers should be used in preference to eliminate the danger of any broken glass finding its way into the hot tub or its surrounds.
  • Alcohol should not be consumed whilst using the spa

If used privately by people used to running hot tubs, the rule about small children can be modified.  People with pacemakers are not recommended to use hot tubs to avoid strenuous activities and higher than usual temperatures.

It is a good idea to request all users to shower before using a hot tub.  Soap in a tub usually causes more bother than it is worth.. if any gets into the system a small amount of Foam Reducer can do the trick.  If non standard chemicals are introduced, the tub should be refilled.  Some owners find it easier and, claim as economic, if not more so to refill tubs rather than long term reliance on Chemicals to control the pH and sanitizer.  It is a matter of debate which route to choose.

Use for any length of time can cause skin to dry out, so it is worth using moisturiser afterwards.

Although not really a safety issue, like the previous observation, users should remember that, paradoxically, it is easy to dehydrate in a hot tub so drinking whilst in a tub for a long period is a good plan.  Remember that alcohol could have the reverse effect, being a diuretic; combined with safety considerations alcohol should not be consumed whilst using a spa.

Health precautions

Make sure the ozone generator is working.  This is a major player in keeping bacteria at bay, especially in the circulation system.  Alternative sanitisers include Chlorine.  Corona Discharge  systems tend to last for up to 5 years where Ultra Violet Ozone systems need the bulb to be changed annually.

Do not over chlorinate.  The maximum safe level is 3-5 ppm.  If you over do it, either partially drain and re-fill to dilute to the right concentration or leave the  cover off and run the jets until it drops to safe levels.  Partial draining and refilling can be the most economical route and the most practical if guests are to arrive shortly.  pH should be kept between 7.2 and 7.6

There is a low possibility of contracting infections so this needs to be reduced to minimal, ideally vanishingly small.  But use of 5ppm of chlorine and other chemicals keeping the balance right should ensure safety.  Some owners choose to drain and refill tubs for every stay to reduce the risk to the minimum.  It is possible to use the same water for two or more months assuming appropriate use of chemicals, maintenance and appropriate management.  This is very much up to the owners.

Legionnaires Disease

The bacteria exist in the environment and the water supply.  However the warmth and, more so, water or air jets in hot tubs where chemical treatment has not been applied ot the right standard, can create a danger of infecting individuals either in the Tub or, even, near-by.  It it, therefore, important to ensure the appropriate chemical treatement regime applies and is carried out.

Some useful safety and other tips:


  • Always take great care and always read instructions;
  • store in a dark cool dry place well away from direct sunlight;
  • make sure childrean cannot access any chemicals;
  • make sure of accurate measurements;
  • always add chemicals to water and not the other way around as this can be dangerous;
  • do NOT pre mix or mix chemicals;


  • Water temperature should not go above 40c
  • For children check the water temperature is around 30c
  • Make sure no alcohol is consumed by hot tub users or before they use it
  • Check with doctors for pregnant women, and those with cardiovascular or blood pressure health concerns
  • It can be an idea to filter water before filling your spa
  • Flushing the plumbing in your tub every so often with a cleaner is good practice
  • Keep a good eye on pH levels and check for calcium in the water ideal levels: pH 7.4; 2-10 parts per million Bromine (ppm); 1.3 ppm Chlorine; 70-170 ppm Calcium; overall alkaline content 70-120 ppm  There is some discussion about these figures; consult with your supplier and take expert advice.

The basic rules are: Drain at regular intervals, keep debris away, make sure the water is properly treated; and service hot tubs every year.


hot tub

This is a taste of the sort of problems and solutions you may face.  Good manufacturers will provide you with check lists and guidance in greater more specific detail.  We hope this gives you a taste of what to expect.

1. The water is not up to temperature

This can be caused by a faulty heater, circulation pump, thermostat or insufficient water. If you notice that the tub recovers heat after use this indicates that the heater is struggling to keep up with the greater demand for energy when people are in the spa. If you are using an air blower, this will create an extra energy demand.  Some tubs turn heaters off when water jet pumps are operating but this can be altered by an electrician depending on the design, power supply and appropriate cabling.

2. Nothing happens

The heating element has shorted or failed.  Water has flooded the air blower (where applicable) or ozonator.  There is an airlock in the pump. Clogged filter. Pressure switch (where applicable) is faulty. You forgot to re-open the shut off valves after cleaning. Closing too many water jets can cause problems.  The heater contactor is faulty.  The inspection door is open and safety switch, where fitted, is breaking the circuit.  A fuse has blown in the electric supply.

3. Ice

If you have let ice form this can cause significant damage depending on how much is formed.  The best route is if the tub is not in use in cold weather, always drain it.

4. Leaks

Leaks are often best dealt with by professional spa people.  Common leaks appear on the joints to the pump and heater.  They can be caused by an uneven platform causing cracks in the structure.  Freezing up can cause leaks.

5. Discoloured water

The filtering system is not working as it should or bacteria are forming.  If bacteria either dose with Chlorine and non cholorine shock or drain and refill.  The big question is, of course, why did the bacteria appear in the first place?  Unless and until you answer this the tub should not be used.  This is very important.
The water has gone green.  Bacteria are having a field day and the tub is in a dangerous state.  Empty it; scrub all accessible surfaces with a solution of chlorine; rinse out using clean water; refill.  Use a compination of Chlorine and Non Chlorine shock afterwards.  For a 300 gallon spa this could come to about 2 table spoons of Chlorine solution with two tablespoons of Non Chlorine Shock.

6. Noisy pump

  • Water level too low
  • Gate or shut off valves closed
  • Filter needs cleaning
  • Airlock in pump
  • Skimmer or wall suction system blocked
  • Air leak in suction line
  • Pump clogged
  • Pump mechanism faulty

7. Pump turns itself off

  • Overheating due to blocked ventilation
  • Pump faulty
  • Timer has completed a cycle

8. Pump will not run

  • Overheated
  • Electric supply faulty or switched off
  • Safety breaker has tripped (Usually a GFCI: Ground Fault Circuit Interrupter).
  • Pump has overloaded

Bottle in all pictures is of course non-alcoholic and the glasses are plastic.