Hot Tub Runnign Costs

Running Costs
True cost of running a hot tub!

How rising electricity bills impact on the cost of running a hot tub.

If you are thinking of buying a hot tub the first question that will probably spring to mind would be “How much will I be paying to run one?”

There is no definite answer to this question as it does not just depend on the cost of electricity alone. It also depends on:

• The dimension and area of the hot tub
• How hot the hot tub is run at
• The temperature of the water that is first used to fill up the hot tub
• How long the hot tub is in use for
• The amount of people in the hot tub at one time
• The ambient air temperature
• The level of insulation inside the hot tub
• The time between water changing

When hot tubs and spas are first made they do not have set running cost assessments for each type of model as this takes much time and it can be very costly. Also, the list above would change the results so they could only be an estimate of the running costs. One producer carried out an investigation that created the results below when the cost of energy was roughly 7 pence for each kW hour.
Two different hot tubs were tried:-

• A small round hot tub with a diameter of 198cm, an ozonator, a filter cycle of 3 hours for each day, a capacity of 919 litres and a two-speed pump.
• A large rectangular hot tub with a length 211cm and a width of 201 cm, a filter cycle of 6 hours for each day, a capacity of 1259 litres, a circulation pump and a two- speed pump.

The temperatures of the hot tubs were set to 37°C and were placed in a room with a natural surrounding temperature of 14°C and the outcome was:-

At the moment the cost of electricity is getting to the level of around 14 pence for each kW hour. At these costs the price for each week of typical hot tub usage would be around £3.78 for the small hot tub and £7.70 for the bigger hot tub.

If the price of electricity in a typical family bill rises by 10% this would only increase the hot tub running price by about 80 pence each week!

If the hot tub cover is left on for the whole time that it is not in use then the hot tub will always keep the water temperature at the set level. It does not cost a great deal to do this as it does not use much electricity because of the insulation features of hot tubs. Once the hot tub has reached its set temperature it will use very little power due to the cover thickness.

The temperature of the hot tub will only drop about 1-2°C each time if it is used for about 30 minutes. It will take little power and time to bring the water back up to the preset level.

The environment of the investigation had a 14°C area temperature, and the results were based on this being the same the same all year round. However the running costs will not always be the same during different times of the year as the outside temperature will drop in the winter and rise in the summer. This means that in the winter the hot tub will have to use more power to keep the temperature up but in the summer will be much reduced.

In a family home it is normally recommended that the owner should change the water every 2-3 months but sometimes other things change this. It depends on three main factors: how often the hot tub is used; how clean the people using it are; and whether the chemical management is correct. The cost for the re-heating of the water if it is changed about 4-5 times a year would be around £20 p.a. The price of the water for each change would depend whether the water supply that it came from was metered or not.

The weekly cost for consumables is rather small as there is a lot less water in a hot tub than in an above ground swimming pool (there is roughly 1000 litres of water in a hot tub). The relevant chemicals will need to be added after a check that should be carried out at least once every week to test the water quality. This could include adding small quantities of some of the following: chlorine, pH Plus, pH Minus, Shock treatment and Spa Clarifier.

Some hot tub owners keep a spare cartridge filter so they can still use the hot tub when the other is being cleaned. The filter cartridges should be cleaned once every 2 weeks, so if you take one out to clean you can place the other straight in to ensure maximum hot tub usage. To clean the filter you must leave it overnight to soak in filter cleaning solution and then let it dry completely. The remaining dirt can then be removed with a brush.