Air Source Heat Pumps for Hot Tubs | Faster Heat?Up & Lower Running Costs

Choosing the right size Most common: 5kW & 9kW

Heat pumps are typically selected based on hot tub volume and how quickly you want to reach temperature. As a rule of thumb:

5kW — most common for 2m × 2m hot tubs.
9kW — also common for 2m × 2m tubs where faster heat-up is preferred.
9kW+ — recommended for larger tubs such as 2.4m × 2.4m hot tubs, and especially swim spas.

Important: A heat pump is an efficiency upgrade — not a requirement. Your hot tub will still heat using its built-in system even if you don’t add a heat pump.

Energy use & heat-up time Quick comparison

Heat Pump Uses just under ~1kW

Typically heats the tub in 2–4 hours (depending on starting water temp and outdoor conditions).

Standard Electric Element

2–3kW element

Can take up to 24 hours to bring the tub up to tmperature from cold.

Heat pumps don’t create heat from electricity in the same way a standard element does — they move heat from the air, which is why they can be more efficient.

Do you need a heat pump? No — optional

Heat pumps are not necessary to warm your spa. Every hot tub includes its own heating system and will heat up by itself. A heat pump is simply an additional option for customers who want:

Lower running cost vs relying solely on the electric element.
Faster heat-up from cold water in many conditions.
More efficient temperature maintenance (especially with good insulation and a quality cover).

Who is it best for? Best-fit scenarios

New installs where you want quicker first heat-up.
High usage households that run the spa frequently.
Larger tubs / swim spas where efficiency gains can be bigger.
Energy-conscious owners looking to reduce consumption vs a 2–3kW element.

Tip: Pairing a heat pump with a well-fitted insulated cover and good cabinet insulation makes the biggest difference.