How To Control a Heat Pump with ANY Hot Tub Spa Pack

With energy prices skyrocketing, it’s no wonder more and more hot tub owners are on the lookout for cheaper ways to keep their tubs warm. While cutting down on use is one option, a better, longer-term solution is to consider an air source heat pump.

 If your setup is compatible, an air source heat pump can be a game changer—I managed to save about 66% on my energy bills after installing one. You can check out that video here. 

In this article, I’ll take you through how to control the air source heat pump directly from your hot tub’s spa pack. And just so you know, there’s no need for overly complicated wiring, fancy relays, or matching brands. Let’s jump in!

You can also find me on my socials;

Controlling Your Air Source Heat Pump

First off, let’s address a common misconception: people often think that the brand of your air source heat pump must match the brand of your spa pack. Not true! I’ve got a Balboa spa pack and a Comfort Line air source heat pump, and they work just fine together.

So, how do we control the air source heat pump without needing a matching setup? It’s all done through water flow. That’s right—no complicated relays, no additional wiring, just controlling the heat pump by using water flow.

Here’s How It Works

When your hot tub calls for heat, it automatically turns on the circulation pump, which would usually activate the heater. Instead, we disconnect the electric heater and let the air source heat pump do the job. Here’s the step-by-step:

1. Water Flow Activation: When the circulation pump turns on, water starts flowing through the system and reaches the air source heat pump. Inside the heat pump, there’s a flow switch that senses this movement. If the water temperature is below the thermostat setting, the heat pump kicks in to heat the water.
2. Automatic On and Off: As soon as the water reaches the set temperature, the spa pack turns off the circulation pump. This stops the flow, and the air source heat pump automatically switches off too. Easy, right?

This setup means you can control the heat pump directly through water flow, without needing any brand-specific or complicated electrical setups.

Powering Your Air Source Heat Pump

To power the air source heat pump, you’ll want to connect it directly to the main power source from your spa pack. Specifically, you can tap into the main three-core cables that come into the spa pack. But, a word of caution—always consult a qualified electrician before making any adjustments to your hot tub’s electrical setup.

Benefits of Water Flow Control

Using water flow to control your air source heat pump has a few big advantages:

• Simplicity: No need to mess around with complex wiring or brand compatibility.
• Flexibility: Since you’re just using the water flow to trigger the heat pump, this setup will work with almost any spa pack.
• Efficiency: The automatic on-off system ensures that the heat pump only runs when needed, keeping energy use down.

Closing Thoughts

So there you have it, by using the water flow control method, you can easily pair just about any air source heat pump with your spa pack and start saving money.

This setup lets you enjoy your hot tub just as much as before but at a fraction of the cost. If you’re ready to make the switch or want to explore your options, check out some air source heat pumps here.

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Fast forward to 2025, I've helped over 1400+ DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi