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Hot Tub FAQs

A wooden hot tub provides the ultimate addition to your backyard or recreation property. Our cedar hot tubs are hand-crafted from 100% Canadian red cedar, giving you quality materials and craftsmanship that will stand the test of time.

Frequently Asked Questions

How big are the hot tubs?

We sell hot tubs for almost any size, small enough for a romantic dip, or big enough for the whole family! Our best-selling model is made for up to six people, but we sell models ranging from 2-8 person capacity.

How much water do the hot tubs hold?
We offer several different sizes of hot tubs. Please see the table below for an approximate measure of hot tub capacity in gallons. 

Hot Tub Measurements

(diameter x depth)

Capacity 

(Gallons)

Heat Up Time

(internal stove, hrs)

Weight

(lbs)

5ft x 3ft

348

2.5

2900

5ft x 4ft

463

3

3850

6ft x 3ft

500

3.5

4160

6ft x 4ft

667

4.5

5550

7ft x 3ft

681

4.5

5670

7ft x 4ft

908

6.5

7560

 How long do the wood-fired hot tubs take to heat up?

Most of our customers find 104° F is the ideal temperature for relaxing. Our wood-fired hot tub takes about 3 hours on average to heat to 104° F. The table above shows approximate heat-up time based on your hot tub size, assuming a starting water temperate of 55° and an internal wood burning stove.

When can I use my wooden hot tub?

You can use your wooden hot tub all year round. It can also be used with hot or cold water. This means you can use it as a refreshingly cool plunge pool in the hot summer months and as a relaxing hot tub in the cold winter months. 

How long will my wooden hot tub last? How do I make it last longer?

Your cedar hot tub should last 10-15 years with appropriate maintenance. To maximize your tubs life, it is essential that you are regularly checking and balancing the chemicals in the water. This includes both checking and adjusting the sanitizer (bromine) levels as well as pH, alkaline, and calcium levels. We have detailed guidance on water maintenance as well as a recommended maintenance plan in our "Care and Cleaning" section.

Cleaning the inside of the hot tub regularly with soapy water using a brush or high-pressure cleaner will also extend the hot tub’s life. Do not paint the hot tub or treat the inside of the wooden hot tub. You do not have to clean or treat the underside of your wooden hot tub.

It is not necessary to coat the tub with a protective finish. Left alone the tub will weather and turn light gray. We recommend that you do not use wood sealer or paints on the tub, because the wood benefits from exposure to the air. The water will seal the interior surface; therefore it is important to leave the exterior surface unsealed so it can breathe.

If you want your tub to have a finished look, you can apply boiled linseed oil to the exterior. It is absorbed into the wood without making a permanent seal. When applying linseed, coat the exterior (only) with a brush or roller. Before disposing of the application tools let them dry out in a non-confined, well ventilated area. They may spontaneously combust if placed in a confined area.

Where can I put my wooden hot tub?

Your wooden hot tub was must be placed on stable, flat ground. We recommend placing the wooden hot tub on a gravel base or a concrete pad. We do not recommend placing the wooden hot tub directly on dirt or grass. Depending on local conditions, a drainage system could be recommended. 

Will my water change color?

When you start using your hot tub, the color of your water may turn dark red or even brown. This is a process called tannin leaching. Tannins are the natural oils / preservatives in the wood.

When you first use the tub, tannins will leach from the wood into water, changing the water's color. The leaching process may last up to 3 months, depending on the wood's tannin content. The tannins are not harmful, but they can discolor bathing suits. If your water has tannins in it, change your water more frequently and eventually, all the tannins will be leached out of the wood.

The vinyl liner helps reduce tannin leaching and our lined hot tubs experience much less leaching than an unlined wooden tub. However, customers should still expect some leaching as the benches, struts, and other pieces in the tub are still made of cedar and contain tannins. 

What is my wooden hot tub made out of?

Your Redwood Outdoors hot tub is made from 100% Canadian red cedar. Cedar is naturally resistant to moisture and rot. It is a strong, elastic, and durable wood. Additionally, red cedar has a beautiful appearance that we know you and your guests will appreciate.

Does my wooden hot tub come fully assembled?

All our hot tubs kits are designed with the DIY customer in mind. Anyone with novice woodworking skills could build the body in approximately 4 hours over 2 days.

The hot tubs are easily assembled by matching the wood components together using the “tongue and groove” principle. All the pieces are pre-cut and there is no cutting or sawing required. 

All the assembler will need is a level, Phillips screwdriver, 7/16″ and 9/16″ open end wrenches, 9/16″ deep socket wrench, vise grips, and a mallet

We do no recommend extending the assembly period beyond seven days. After 7 days, the wood may start to warp if not fully assembled.

If you have purchased an electric hot tub, you must work with a qualified electrician to wire the electrical components. We also recommend working with a plumber to install the water piping, however, the piping can be installed by a customer with more DIY experience.

Are there any special set-up instructions?

If you are using the hot tub without a liner, there is a specific method when filling your new wooden hot tub for the first time.

First, fill the water (usually with a hose) until it reaches the 4-inch (10 cm) mark. Leave the hot tub like this overnight. This will allow the wood to swell and make the hot tub walls and floor dense and consistent.

Each day, add four inches of water (10 cm) and let it sit overnight. Continue this process each day until the hot tub is at 80% capacity. This will allow the wood to swell and help extend the life of your wooden hot tub.

If you are using your hot tub with the liner, you must fill your hot tub up once during the assembly process to let the liner set. This is done before benches or other components are installed. Let the hot tub sit for ~24 hours filled with water. After 24 hours, drain the tub and continue assembly.

What can I add to the hot tub water?

You may add any natural and biodegradable products to the water for relaxation purposes. Some customers add salt, herbal extracts, or essential oils to heighten your hot tub experience. Adding non-biodegradable products to the water could cause bacterial/algae growth.

You must maintain the water with a sanitizing agent (bromine) as well as maintain the water pH, alkaline, and calcium levels. If you are adding other products to the water (such as essential oils) this may impact your levels and interact with your sanitizing chemicals. Check the label and consult with your local spa chemical dealer before adding any foreign substances to the water.

How do I manage the ash from the oven?

How often you clean out the ash depends on how often you use your wooden hot tub. For infrequent users, once a month should suffice; for frequent users, we recommend clearing out the ash once a week. Use a shovel to remove the ash. 

How often should I drain my wooden hot tub?

If you have a wood-fired hot tub, you should change your water every 2-3 weeks.

If you have an electric hot tub with a properly maintained filtration system, you should change your water every 3 months, however, your water filter must be cleaned regularly.

How long can I leave my wooden hot tub empty?

If you hot tub is unlined, you should not let it sit empty for an extended period of time. This can cause the hot tub to dry out, and can cause warping, affecting the hot tub’s density and consistency.

If you are using the liner included with your hot tub, the hot tub can sit empty without impacting the tub's shape.

If your wooden hot tub sits empty for a long time and the tension straps fall down, follow these instructions:

  • Using short screws to avoid damaging the stave or the wall, screw four screws underneath the tension straps into the wood.
  • If the tension straps are very loose, you should tighten them carefully until the staves are even and fixed to the floor section.
  • Fill the hot tub with 2-4 inches (5-10 cm) of water so that the hot tub floor can become consistent again.
  • Please note that the tension straps must be loosened gradually over time. If the straps are kept too tight, the hot tub will not become dense and consistent.

I left my wooden hot tub empty for a long time. Do I tighten the tension straps?

Not under normal circumstances. The tension straps are made so they do not have to be tightened. The dry wood absorbs the water, swells, and becomes dense and consistent.

My wooden hot tub is sitting empty. Should I cover it?

No, you should not. Air needs to circulate in the hot tub to prevent the formation of mould.

Is my wooden hot tub portable?

Yes it is. If you are redesigning your yard or landscaping, you may move your wooden hot tub to a different location, depending on its weight.

How much does it weigh?

The entire shipping weight of a 6' x 4' kit is approx. 675 lbs including crate. The tub minus the stove and benches can be easily carried by 4 people.

How do you control the temperature in a wood-fired hot tub?
Start out with a roaring fire until you get close to the target temperature, say 95F, then reduce the size of the fire until it reaches 102 F - 104F. When you get to tub temperature keep a small fire going. The fire can also be slowed down by adjusting the draft. It is better to control temperature by fire size than by closing the damper because a build of up creosote can result. It is also easy to cool down the tub just by adding cold water.

If you have an electric hot tub, the tub's temperature can be set using the heater.

How much wood does a wood-fired hot tub consume?
A moderate size wheel barrow load of DRY wood.

Does the tub come with a warranty?
We offer a limited warranty against manufacturing defects on our all wood products, but because wood is a natural product we cannot take responsibility for natural wear and degradation that may occur over time. Visit https://www.redwoodoutdoors.com/warranty for details on the Redwood Outdoors warranty policy.

General Warnings:

  • Fire and hot water can cause injuries. Do not leave children unattended around the wooden hot tub.
  • Please do not use the wooden hot tub when under the influence of prescription medication, alcohol, or recreational drugs.
  • Do not leave the hot tub unattended when the stove is burning.