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Top 5 Tips for Buying a Hot Tub or Spa – Part Four: Energy-Efficiency


This is the fourth post in the series “The Top 5 Tips for Buying a Hot Tub or Spa.” In this series we will discuss the most important considerations when choosing the hot tub that is perfect for you. Each day we will cover one of the top five tips with a new post and we encourage you to leave your comments, thoughts or opinions below.

Tip #4: Energy-Efficiency

There are many important factors pertaining to a hot tub’s energy-efficiency such as heat retention, insulation, filtration, design, and engineering. Several years ago, a spa cost a lot of money to operate each month, especially in colder climates. Over time, hot tubs have become more energy efficient in their design, construction, and performance in order to comply with certain energy standards, most notably, Title 20 established by the California Energy Commission (CEC). Not all hot tubs are made equally and not all are compliant with these energy standards, so be sure to ask your dealer or do some research on your own before making a purchase.

Heat Retention

The key to higher energy-efficiency and lower monthly operating costs is heat retention. Insulation is very important in keeping the heat inside your spa, as well as keeping the cold out. Spa manufacturers use different methods for insulating their spas, so it is a good idea to know what to look out for. These methods include: filling the entire cabinet with foam, insulating the underside of the shell, and insulating the inside of the cabinet. Some manufacturers also use a lower density foam, resulting in a less energy-efficient hot tub.

Your spa’s cover is an integral part of keeping the heat in your spa. As we all know, heat rises; just like in our homes, which is why we place vast amounts of insulation in our attics. It is the same for a hot tub. The cover is the last line of defense for heat retention. Make sure your spa includes an energy-efficient cover with a decent R-value (usually R-12 or more) and high-density foam. When the hot tub is not in use, you will want to make sure that the cover straps are latched and the cover fits snugly to minimize heat loss. Cover straps are also a great safety feature as well, to keep out children and unwanted visitors.


We talked a lot about filtration in the previous section of this series, and it also plays a large part in heating the spa as well. Water needs to be able to flow easily through the filter in order for it to be heated and cleaned. If your filter cartridge is old, dirty, or simply clogged up, it is either time to clean it or replace it. In fact, if you own a spa and it is having trouble heating or keeping a consistently warm temperature, you may want to clean or replace the filter cartridge. This is one of the first things a spa service technician will check and you may save yourself a large diagnostic fee by looking at it first. If you think your filter may be the problem, remove the cartridge for a few hours and see if it makes a difference in the temperature. If so, clean the filter or replace it. For average hot tub use, a good rule of thumb is two replace your filter cartridge every two years.

Filtration cycles are normally set to four hours, twice per day; but these can be adjusted based on bather load and usage patterns. Just make sure to run the cycles enough to maintain clear, clean water. Also, running your filtration cycles during off-peak hours is always a good idea.


When shopping for a spa, do not base the effectiveness of hydrotherapy or massage solely on the number of jets and the size of the pumps. Some hot tub manufacturers place a very large emphasis on the total jet count, while others tout the size of the pumps as a major selling point. The more jets it has, the more horsepower required from the pumps, and the higher your operating costs. A spa does not need hundreds of jets in order to provide a great massage, so watch out for this selling tactic. How many jets is too many? Well, I guess that is up to you. This is why wet-testing is important, along with researching the model(s) you are considering.

Let’s discuss pumps and horsepower for a minute. Do not be fooled by the brands or dealers that peddle high horsepower as a major selling point. In many cases, they are referring to the Brake Horsepower or BHP. Brake Horsepower (BHP) is the horsepower a pump motor achieves for a brief period upon start-up. It does not run at the full BHP the entire time, which would be overkill for most spas. This is a widely used tactic amongst the spa industry, so be sure to seek clarification if you have any questions about it.

Many spa models may include an independent circulation pump, which operates continuously to filter and heat the water. Circulation pumps use a smaller amount of electricity than jet pumps, so it will assist in lower monthly operating costs. They also run quieter than models that do not have circulation pumps, which may be nice if the spa is sitting outside of your bedroom or on a deck. These models usually cost more than models without circulation pumps and are available from many different manufacturers.

Following these simple guidelines when shopping for a hot tub will greatly increase your chances of purchasing a spa that will be long-lasting and one of the most energy-efficient models on the market today. And remember, always ask questions to your dealers or private sellers in order to make a fully-informed buying decision and wet-test when possible. In most cases, your spa’s operating costs should be able to average less than a dollar a day.

Tip: An energy-efficient thermal or floating spa blanket will help retain heat and reduce the amount of moisture building up on the inside of your spa cover, which can extend its life.

If you missed the first part of this series you can find it here:

–> Top 5 Tips for Buying a Hot Tub or Spa – Part One: Comfort

–> Top 5 Tips for Buying a Hot Tub or Spa – Part Two: Therapy

–> Top 5 Tips for Buying a Hot Tub or Spa – Part Three: Filtration and Maintenance

As always, we would love to learn from your thoughts and questions in the comments below…

Other Helpful links:
California’s Appliance Efficiency Program
Title 20, California Code of Regulations
Online Hot Tub Energy Calculator (We do not have any affiliation with this product or online tool)

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7 Responses to Top 5 Tips for Buying a Hot Tub or Spa – Part Four: Energy-Efficiency

  1. DedraQ February 14, 2011 at 11:35 am #

    I agree in making the R-rating number one in choosing an energy efficient spa. I think people put too much emphasis on “Stand-by Wattage” which really just makes your hot tub ineffective in hydrotherapy (no one wants a weak hot tub!). I think more people need to know that, so thank you for your article! http://www.thegardenspas.com


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