Not all hot tub insulation is created equal. In fact, in some spas it’s practically non-existent.
And that matters.
Hot tub insulation is what makes a hot tub ‘hot’, by keeping more of that luxurious heat in. The better the insulation, the greater the ability for your spa to create and retain warmth.
The knock-on effects of great insulation extend to comfort, running costs, heater maintenance and more. In fact, insulation is perhaps the most important consideration for anyone who is considering buying a hot tub.
So what does good (and bad) hot tub insulation look like? In this guide we’ll look at precisely that, guiding you through your different options and the difference they will make to your soaking and ownership experience.
Why is hot tub insulation important?
Hot tub insulation is one of the most important considerations when purchasing a hot tub. Insulation defines your spa’s ability to maintain the warmth of the water (and to a lesser extent, its ability to efficiently warm the water in the first place).
High performance insulation ensures minimal heat leaks out, making for a more comfortable soaking experience while reducing the workload of the spa heater.
With your heater doing less work, it uses less power. Quality insulation is one of the key ways to reduce the heating costs of your spa, potentially saving you thousands of dollars over the life of the spa. In the best spas, insulation works in concert with other energy efficient technologies, such as always-on circulation systems that keep your water warm and fresh, and clever jets that transfer the spa’s internal heat back into the water.
There are other perks too:
- A warmer soak for longer: While cheap spas can struggle to create and keep their heat, particularly in chilly conditions, quality insulation allows you to maintain a perfectly stable temperature for longer, and with less power.
- Always warm, always ready: When your spa retains heat while using minimal power, there’s no need to ever turn it off. You can have a soak whenever you choose, no preparation or waiting required.
- Maintenance and longevity: Quality insulation means your heater doesn’t have to work as hard, which can extend its life. You won’t have to repair or replace the heater – or your entire spa – as early as you otherwise might.
In short, while it’s hidden away, and therefore easy to overlook or ignore, insulation is one of the most critical considerations – perhaps the most critical consideration – for anyone shopping for a hot tub.
What are the different types of hot tub insulation?
Hot tub insulation comes in a surprising array of types and varieties. Let’s break down the most common options, to understand exactly what you can invest in and what to expect in terms of performance.
1. None at all
The cheapest hot tubs on the market come with little to no insulation. While this approach might lower the upfront cost of the spa, it significantly increases the ongoing costs, as the heater has to work overtime to maintain the warmth of the water (and it often won’t even be able to do that).
Ultimately, this ‘cheap’ option can end up costing you significantly more in the long term, not just through higher electricity bills, but in the maintenance needs and shorter lifespan of a lower quality spa.
Pros: Lower upfront purchase price.
Cons: Extremely poor heat retention, high running costs, water cools quickly, heaters work overtime, not environmentally friendly.
Heat loss: Unsurprisingly, a lack of insulation sees heat leak away fast, with the water losing ~2.8C per hour.
2. Foil
Foil-insulated spas, aka thermal wrap spas, feature a thin reflective blanket within the spa cabinet. The idea is that radiant heat from the warmth of the water and the heat generated by the spa’s internal heat pump or pumps is reflected back into the machine. A great idea for sure, but one that, in practice, isn’t very efficient at all. It’s fine for lower temperature pools, but it simply can’t handle the demands of higher temperature spas or external cooler environments.
The main draw here is that the cost to manufacture a product with foil insulation means they can meet the market at a much lower price point for purchase. However, the consumer pays the costs over the duration of spa ownership with higher running costs. The ongoing costs of hot tubs with this low-quality insulation are higher and can be an indication of lower all-around build quality and material used for the spa.
Pros: Better than nothing, lightweight, inexpensive to manufacture.
Cons: Minimal insulation value, does little to trap heat, still results in high energy bills, performance drops even more in cold or windy environments.
Heat loss: Thin and only built to deal with radiant heat, foil insulation causes your spa water to lose ~1.5C per hour.
3. Spray-on shell
A type of foam insulation, here the hot tub shell is sprayed with a layer of foam inside the cabinet, creating a barrier designed to reduce the amount of heat that leaks away from the water and out through the shell.
While spray-on shell foam is once again better than nothing and a bit more effective than foil, it still doesn’t offer a huge amount of heat retention, as large amounts of insulated space are left empty within the cabinet, where heat can leak out and cold can leak in. It may be an option for budget-conscious buyers who use their spa occasionally and in mild conditions, but you need to be aware that comfort levels and running costs may not be ideal, especially if you live in cooler climates.
Pros: Provides moderate insulation, considered more effective than foil and may help strengthen the shell.
Cons: Still leaves large gaps of uninsulated space, heat escapes through the cabinet and base of the spa, not hugely energy efficient.
Heat loss: Not much better than foil, with your spa water losing ~1.4C per hour when the heater is turned off.
4. Edge-to-edge full foam
The gold standard in hot tub insulation, this option sees high-density foam completely filling the spa cabinet. It surrounds the shell, the plumbing and the internal machinery, creating a thick barrier that keeps heat in and cold out. It’s the same high-performance insulation technology that’s used in commercial freezers and other extreme temperature environments.
While it commands a more significant upfront investment, edge-to-edge insulation offers incredible benefits and returns. Used in the world’s most premium and energy-efficient hot tubs, this type of insulation has been proven to significantly reduce heating costs while keeping your spa water at optimal temperature for longer.
In fact, the edge-to-edge insulation found in Hot Spring hot tubs is so efficient that you never have to switch your spa off. It’s designed to run 24/7/365, so it’s always warm and ready for a soak whenever you are.
Pros: Maximum heat retention for longer, lowest heating costs, protects the spa’s important internal machinery and is considered more environmentally friendly due to lower heating costs.
Cons: Higher upfront cost (though this is more than paid back over time).
Heat loss: By far the best heat retention, with your water losing just ~1C per hour when the heater is off.
The Hot Spring Difference
Hot Spring hot tubs are built for those who understand that the highest quality spas also deliver the best value. Backed by Watkins Wellness, the world’s largest and innovative hot tub brand, this is what has made Hot Spring the most popular and trusted name in New Zealand spas.
At Hot Spring we don’t sell spas without insulation. We don’t even sell spas with foil or spray-on foam. All of our spas feature high quality and ultra-efficient edge-to-edge insulation regardless of the spa range, here’s a breakdown of what you can get for each collection:
|
Collection |
Type of Material |
What You Get |
|
Highlife |
Polyurethane Foam |
Multi-density insulation (40lb, 3.5lb, ½lb) with the majority 3.5lb; layered, freezer-style heat lock for maximum efficiency. |
|
Limelight |
FiberCor® |
Proprietary wool-like insulation compacted to 2.0lb density; 4x denser than standard foam for superior heat retention. |
|
Hot Spot |
FiberCor® |
Proprietary wool-like insulation compacted to 2.0lb density; efficient full-cavity coverage for consistent warmth. |
|
Freeflow |
Polyurethane Foam |
Industry-standard ½lb density foam used by leading brands; reliable, entry-level insulation providing dependable warmth. |
If you want a hot tub that delivers a consistent, reliable soak for longer, engineered for ultimate comfort and to enhance your lifestyle, it’s got to be a Hot Spring. We offer Australia's most energy efficient hot tubs, as proven by independent lab testing. With running costs as low as $1 a day, you can relax knowing you won’t be shocked by a high power bill, and that you’re getting a level of quality and reliability that gives you ultimate peace of mind.
Our spas are so well insulated and efficient, in fact, that you never have to turn them off. You can keep your spa at your ideal temperature all year round. It’s always ready for a soak at the drop of a hat – no pre-planning, no prep work, no waiting required.
Add in unmatched longevity, up to 90% less maintenance and the most luxurious in-spa experience on the market and you’ve got a hot tub that ticks every single box.
Insulation is one of the most – perhaps the most – important factor to consider when you shop for a hot tub. And insulation is simply better in Hot Spring spas.
Ready to experience the Hot Spring difference? Shop our range today, or visit your local dealer.
