Revolutionize Your Hot Tub With An Air Source Heat Pump!

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By Debarghya Roy


Hot tubs are a great way to relax and unwind after day’s work. But, standard electric heaters for hot tubs use up an excessive amount of electricity making them energy-inefficient and expensive over time. Thankfully, technology has come to the rescue in the form of air source heat pumps.

air source heat pump for hot tub

An image showing a hot tub with a connected air source heat pump

Key Takeaways

  • Air source heat pumps are a cost-effective and energy efficient alternative to traditional electric or gas powered hot tub heating systems.
  • Air source heat pumps use refrigerant to transfer outdoor air into usable thermal energy for your hot tub, resulting in reduced monthly electricity bills.
  • Different types of air source heat pumps such as air to water models, ducted fans, and ductless mini splits can be used depending on the climate and size requirements of your hot tub.
  • Thanks to their greater efficiency ratings (up to 350%) when compared with standard electric/gas fired solutions investing in an ASHP could give you long term savings up to 70% annually while still keeping water temperature steady no matter the weather!

Definition And Principles

An air source heat pump is an efficient, cost-effective way to maintain the temperature and keep your hot tub operational. It works by transferring the ambient energy from outside air into usable heat for a hot tub.

The compressor takes in outdoor air and compresses it until it reaches a high enough temperature to warm the water in the hot tub. 

The compressed molecules are then sent through copper coils containing refrigerant that transfers heat energy to transferable form which is then used to increase domestic heating temperatures of up to 30 0C or lower depending on requirements.

This process happens multiple times per hour, making sure that water temperature remains steady at all times without sacrificing other aspects such as humidity control or atmosphere.

Advantages Of Using An Air Source Heat Pump

Using an air source heat pump for hot tubs has numerous advantages, all of which can lead to substantial cost savings and a more environmentally friendly approach to heating the water. 

When compared to traditional electric heaters, air source heat pumps are much more energy efficient because they use far less electricity. 

As a result, homeowners will be able to keep costs down on their monthly utility bills since it takes much longer for an air source heat pump unit to reach the desired temperature than with a standard heater. 

Additionally, these pumps transfer warm air from outside into the hot tub’s water tank at no additional cost since there is no need for propane or gas-fired boilers as backup sources of fuel. 

The Vian Power S9-PLUS system operates quietly and efficiently due its advanced technology that helps maintain consistent temperatures in any weather condition while also protecting against overcharging or overheating. 

Finally, these systems promote eco-friendly practices since they facilitate renewable energy use rather than nonrenewable resources like oil and gas burning power plants.

Mechanism, Efficiency and Performance Of An Air Source Heat Pump Work For Hot Tubs

An air source heat pump uses refrigerant to transfer the heat from the outside air into your hot tub, providing a quieter and more efficient way of heating.

Explanation Of Heating And Cooling Mechanism

It works by taking heat from the outside air, boosting it up using a compressor, and then transferring that energy into your hot tub or swimming pool.

The process starts with a refrigerant passing through copper coils inside the system’s compressor and condenser unit. 

As it passes through the copper coil, its temperature increases due to compression of the gas molecules by the compressor blades. This creates very hot gas which then transfers its heat to an exchange medium in the form of a liquid solution such as glycol (ethylene glycol).

Energy Efficiency

Air source heat pumps have an efficiency rating of around 350%, which is significantly higher than your typical hot tub heater. 

This means that for every unit of energy used, you can expect to get 3.5 times as much heating output compared to using a conventional electric heater or gas-fired water heater.

The impressive efficiency ratings, combined with the ability to extract free energy from the air and transfer it in an efficient manner make these types of systems a cost-effective choice for many people looking to save on electricity costs associated with their hot tubs.

In addition, this technology is widely adopted in the pool industry due to its significant potential highly consistent temperature control throughout operation and over time savings, with users reporting up to 70% off their regular electricity bill thanks to the introduction of this system into their home or business.

Nowadays more and more people are looking for ways in which they can reduce household electricity bills without having too drastic change how they operate at home or work building installing an air source heat pump takes care just that. 

The initial investment may be higher but upon completion it quickly pays itself back multiple times over making sure you’re able to enjoy convenient heated water supply all year round while still minimizing those expensive electrical costs each month; especially if living temporarily without access other options such as natural gas available.

Performance In Cold Temperatures

Air source heat pumps can still be used to heat up hot tubs even in cold climates. The performance of an air source heat pump is partly dependent on its model and is affected by the temperature outside.

Generally, the efficiency of an air source heat pump declines as temperatures drop below 0°C or 32°F due to increased resistance from thicker insulation layers around pipes and central compressors that are designed to protect against freezing weather.

For optimal performance, Arctic grade models are recommended for sub-zero climate where temperatures dip lower than -15°C (5°F). These units have larger capacities ranging from 4.5 kW to 14 kW of heating power which will quickly bring your hot tub up to comfortable temperature within minutes.

Types Of Air Source Heat Pumps For Hot Tubs

Air-to-Water Heat Pumps

Air-to-water heat pumps are a type of air source heat pump commonly used for hot tubs and swim spas. The pump works by taking in outside air, converting it into energy, then boosting the temperature to the desired level before transferring it to the water.

This means that you can save up to 70% on your heating costs compared to electric or gas powered heaters. The brilliance of this technology is that even in cold climates where temperatures dip below freezing, an air source heat pump still performs optimally. Some models are able to keep water heated at 37°C or higher when external temperatures drop as low as -25°C.

When shopping for an air-to-water heater pump, consider factors such as size and capacity requirements, installation processes and safety measures, maintenance needs and troubleshooting tips which can vary based on model selection.

Ducted Air Source Heat Pumps

Ducted Air Source Heat Pumps (ASHP) are an energy efficient and cost-effective way to heat hot tubs. These systems use outdoor air temperatures as a source of heating, meaning that they can offer substantial savings when compared with conventional electric or gas-powered hot tub heaters.

ASHP’s take advantage of external temperatures by using a compressor, evaporator coil, and condenser fan to transfer the warm or cool air from outside into the hot tub area.

The process is referred to as the refrigeration cycle because it involves extracting warmth from the outside air which then circulates around your hot tub allowing for all year round bathing pleasure.

Energy efficiency and cost savings derived from Ducted ASHPs make them ideal for any homeowner looking for sustainable heating solutions without breaking the bank. As mentioned previously, these units require minimal maintenance and with normal operations will not need attention more than once every couple of years depending on usage patterns.

Ductless Mini-Split Air Source Heat Pumps

Ductless mini-split air source heat pumps are a unique option for hot tub heating. They consist of two components: an outdoor compressor/condenser and one or more indoor air-handling units, which allows for flexibility in installation.

These systems generally require no modifications to the existing ductwork, can be used to cool as well as heat, and operate almost silently. 

Mini-splits are also incredibly energy efficient when compared with traditional electric resistance heaters or even other types of air source heat pumps because they extract latent energy from the ambient air outside rather than producing it independently through friction.

Installation costs range from $1,500-$5,000 depending on complexity and scale. However these costs may be offset by long-term savings since they typically use less electricity than conventional SpaHeaters while maintaining consistent temperatures even in cold climates.

Pros And Cons Of Using An Air Source Heat Pump For Hot Tubs

Understanding the pros and cons of using air source heat pumps for hot tubs is essential for making informed decisions about your hot tub heating system. 

The following table provides a comparison of the advantages and disadvantages of air source heat pumps to help evaluate their suitability for your needs.

Energy Efficiency: Air source heat pumps can save up to 70% in heating costs compared to electric heaters, making them a more cost-effective option.Temperature Limitations: Air source heat pumps may not work as efficiently in extremely cold temperatures, which can affect their overall performance during winter months.
Environmental Benefits: Using an air source heat pump reduces harmful emissions and consumes less energy, making it an environmentally friendly option.Higher Initial Cost: The upfront cost of an air source heat pump can be higher than that of a traditional electric heater, but the long-term savings may outweigh the initial investment.
Higher Heat Output: Air source heat pumps output more heat than electric heaters while using less energy, providing better overall heating performance for hot tubs.Noisy Operation: Some air source heat pumps can be more noisy than traditional heating systems, although there are quieter models available on the market.
Lower Long-term Costs: With reduced energy usage and lower maintenance requirements, air source heat pumps offer lower long-term costs when compared to traditional electric heaters.Professional Installation: Air source heat pumps require professional installation, which may add to the overall cost of your hot tub heating system.

To mitigate the cons of using air source heat pumps for hot tubs, consider installing a backup heating system for use during extremely cold temperatures, invest in a high-quality and quieter model, and ensure proper installation and maintenance by a professional technician. 

Energy Efficiency Of Air Source Heat Pumps For Hot Tubs

Air Source Heat Pumps offer unbeatable energy efficiency with up to 6.4 COP (Coefficient of Performance), making them up to 80% more efficient than traditional heating systems, and resulting in long-term cost savings for hot tub owners.

Comparing Energy Usage With Traditional Electric Heaters

To understand the energy efficiency advantages of air source heat pumps (ASHP) for hot tubs, it is essential to compare their energy usage with traditional electric heaters. The following table illustrates the differences between the two heating options:

Air Source Heat PumpsTraditional Electric Heaters
Efficiency rating of around 350%Efficiency rating of 100%
Can provide up to three times more heatProvides a 1:1 ratio of energy input to heat output
Produces up to three times more power than they useConsumes equal amount of power as they produce
Lower carbon emissions due to high efficiencyHigher carbon emissions due to lower efficiency
Works best in areas with renewable energy gridsDoes not take advantage of renewable energy sources

Cost Comparison Between Air Source Heat Pump Vs Traditional Heat Pump For Hot Tub

A heat pump can potentially help you save up to 80% on your hot tub heating costs. Make sure to compare the lifetime cost against traditional hot tub heaters before selecting the right one for your needs.

Cost ComponentAir Source Heat PumpTraditional Heat Pump
Initial Purchase Cost£2,000 – £3,500 (varies based on size and capacity)Varies widely, typically more expensive due to ground source systems
Installation CostTypically lower than traditional systems due to fewer required external unitsTypically higher due to the complex installation of ground source systems
Energy Usage Cost (per kWh)4.9 cents to 6.5 centsUp to 9 cents or more
Operational Cost in Cold Climate (per hour)Approximately £2 (assumes an electricity cost of 20p per kWh)Approximately £4 (assumes an electricity cost of 20p per kWh)
Annual SavingsCan add hundreds of pounds each year in savings compared to electricity-powered systemsNone
Efficiency and Renewable Energy UsageUses renewable energy sources like sun and wind, converting thermal energy into electrical output efficientlyTraditional methods generally use more electricity and may not utilize renewable energy sources as efficiently

Air Source Heat Pumps For Hot Tubs In Cold Climates

A properly installed and sized air source heat pump can provide efficient, economical hot tub heating in extreme cold climate conditions.

Effectiveness In Various Weather Conditions

Air source heat pumps are incredibly efficient and reliable in most climates, keeping hot tubs profitable even in frigid temperatures. 

The Arctic Circle Heat Pump is a good example of a highly efficient air source heat pump that can produce between 14 kW to 4.5 kW of heating power while operating at low temperatures down to -6ºF.

Other types of air source heat pumps may not perform as well when the outside temperature drops below 45ºF – 50ºF range, although specialty models designed for cold weather use may fare better with extra insulation and more robust capacities compared to standard units. 

So it pays off to do some research ahead investing into one such product. Additionally, many pool and hot tub owners choose backup heating options like solar panels or using traditional electric water heater on standby just in case the air source heat pump fails unexpectedly during extreme weather conditions.

Backup Heating Options

Backup heating options may be necessary to provide a reliable source of heat and hot tub temperature when using an air source heat pump. Without the use of backups, hot tub users run the risk of losing their desired hot tub temperatures due to extreme weather conditions such as excessively cold temperatures or snowfall in regions with poor insulation. 

Backups can come in the form of electric water immersion heaters or gas boilers which can both work on their own power sources, working independently from the main heating system while providing short-term and longer-term temperature solutions in various climates and weather situations. 

Electric immersed heaters usually feature thermostatic control that guarantees consistent water temperature even without being connected to a central heating circulation system. Gas boilers are also commonly used because they are easy to install for larger pools and spas, as well as offering great flexibility over different thermal zones within each pool or spa area. Additionally, backup heating systems present potential efficiency savings and reduce need for larger capacity air pumps if further optimizations are needed when conditions warrant it.

Choosing And Installing An Air Source Heat Pump For Your Hot Tub

Choosing and correctly installing the right size heat pump for your hot tub can be a tricky process, so make sure to do your research before taking the plunge.

Factors To Consider While Choosing 

  • size

Choosing a pump that’s too large or powerful can be wasteful and expensive, whereas choosing one that isn’t powerful enough won’t give you sufficient output. 

An inadequately sized heat pump may not provide optimal efficiency and comfort, even while operating within its rated range or design capacities.

  • Power

The power of your air-source heat pump should match the maximum load your system will experience during use. Too much power will result in inefficient operation and higher energy bills.

  • Capacity

You’ll need to make sure there is sufficient unit cooling capacity to cover peak temperatures so that it doesn’t fail under pressure. This includes temperature extremes such as periods of cold weather conditions without adequate heating capability leading to breakdowns. Also be aware of wind chill factors if running pumps outdoors exposing then directly into the elements.

Proper Installation Techniques

Properly installing an air source heat pump for a hot tub is essential in order to ensure the highest level of efficiency and cost savings. When considering installation, there are several important factors that must be taken into account such as location, size, and insulation.

  1. Location: It is best to install the heat pump at least 3-4 feet away from your hot tub or other sources of direct sunlight and at ground level if possible, as this allows for better airflow and more efficient performance.
  2. Sizing: Choosing a heat pump that is correctly sized for your particular system will better ensure optimal energy efficiency while providing the exact amount of heating needed without overcompensating or creating further problems due to underequipped power output levels.
  3. Insulation: Insulating both the heat pump itself as well as its pipe work can help improve efficiency by eliminating any potential temperature loss before transferring it to your hot tub indoor or outdoor unit alike depending on which type you have chosen.
  4. Equipment & Tools Needed: Professionals should also take care in ensuring they have all necessary equipment and tools on hand prior to beginning installation including drill bits appropriate screw anchors, piping adhesive tape/glue sealant etc.
  5. Risks & Challenges: Installing an air source heat pump requires training in correct safety measures therefore it is advised all professionals become familiar with local regulations regarding safe electrical practice procedures paying careful attention when connecting or working around power sources and keep others away from danger areas near water connections.

Troubleshooting Issues, Causes, And Solutions

Troubleshooting IssuePotential CauseSuggested Solution
Thermostat setting not accounting for outdoor temperaturesSettings not adjusted frequently enough to account for seasonal variationsRegularly check thermostat settings to ensure they accurately reflect both indoor and outdoor temperatures
Frozen evaporator coil leading to increased pressures in compressorCold weather conditions and lack of periodic inspectionInspect the condensate drain pan and coils regularly, especially during colder weather conditions
The hot tub’s power supply voltage output doesn’t match its rated specificationsPower supply issues or incorrect voltageCheck your hot tub’s power supply voltage output against its rated specifications label located near the main circuit box or contact the manufacturer’s service hotline support for assistance
Frayed or loose connectors related to the wiring harnessesGeneral wear and tear or faulty wiring setupDisconnect power supply at the breaker switch, examine and rewire the connectors if necessary, then retest the system after reconnecting correctly

Maintenance Routines

Regular maintenance is key to keeping your air source heat pump running optimally and avoiding any costly breakdowns. Here are some simple but important maintenance routines that should be regularly followed:

  • Clean the filters on the unit every few weeks. Debris can accumulate over time, reducing airflow and efficiency.
  • Inspect all electrical connections for any damage or wear and tear as well as ensuring they remain secure.
  • Check to make sure cooling fans are working properly since these help disperse extra heat generated by the pump when in operation.
  • Test temperature cut off settings to confirm appropriate levels of heating & cooling within a safe range using an accuracy thermometer probe.


Air source heat pumps offer hot tub owners a cost-effective and eco-friendly way to heat their spa water. By using an air source heat pump, hot tub owners can reduce energy costs dramatically while also reducing their carbon footprint. Unlike traditional electric heaters, which consume large amounts of electricity even when the water temperature doesn’t need to be adjusted or increased, an air source heat pump only consumes energy when necessary. This makes it more efficient and cost effective than other heating systems. Heat pumps produce up to 6x more energy output compared with the same amount of input electricity which is why they are so popular for pool and hot tubs heating purposes. An air source heat pump can cut your yearly operating costs by as much as 80%, saving you money right away that would have gone towards high electricity bills from conventional electric and gas options.


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