Choosing a Bathtub | Tub Purchasing Guide

Alcove, undermount, drop-in, 2 person, room for a shower? There are a lot of questions surrounding the search for a tub. How do you choose the perfect bathtub? We developed this guide to help you sort through the piles of information. Although it won't answer every question, it will give a good foundation. For more questions - we are here for you: 866-380-0303

Find the Perfect Bathtub Style & Size for Your Bathroom

Scroll down the page to read through all the tub information or use the links below to learn about size considerations, differences in tub style, or common tub options.

Choosing a Bathtub Quick Links:

What Size Tub?

When planning for a bath the first worry is the over all size of the tub. Will it fit into the space restraints? Will it fit through the bathroom door? Will it be a comfortable fit?

Outside Dimensions
Measuring for the tub size
The outside dimensions will let you know if the tub will fit your space and whether it can fit through the door. Remember tubs can be turned sideways to carry it into the bathroom. So the height of the tub needs to fit through the width of the bathroom door.

Tall tubs are great for giving a deep water level on the inside. Shorter ones are great for tub/showers since you are not climbing over a tall rim on a daily basis. When used as a tub/shower we suggest keeping the height around 20".

There is a difference between bathtub height and water height. The bath height is from the bathroom floor to the top of the tub rim - step over height. The water height is from the floor of the tub to the bottom of the overflow - soaking depth.

Bathing Well
Inside Bathtub Dimensions
How large of a bathtub to bathe comfortably? Bathing well is measured at the bottom of the bathtub - the length and width of tub floor. To see if a tub will fit for you - lean or sit against a wall and measure from the wall to your toes. Check this measurement against the tub's technical sheet for comparison. Will you be able to stretch out sufficiently? Is it wide enough to sit comfortably?
Sitting in a bathtub, upright or slouch?
Also think about how you lounge. Do you sit against the back slope or do you slouch? I slouch down into the bathtub, making the length of the bathing well not as important as the width and water depth.

Backrest Angle
Inside Bathtub Dimensions
A 90° angle would be sitting straight up - not very uncomfortable! According to Cornell University "Ergonomics of Sitting" a comfortable chair is with a 15° angle. Wood Magazine "Must-have measurements for comfortable seating": "Slant the back, up to 5° for a formal chair and up to 15° for a casual chair". As I reached this further there are complicated rules when it comes to chair design: "as the back angle increases, you need to up the seat angle (to maintain the seat-to-back angle between 90° and 100°) to prevent forward sliding" - also Wood Magazine. What does all this have to do with the backrest of a tub?
1) An exercise to understand the backrest angle give on a technical sheet
A protractor will help you visualize the backrest angle. A technical sheet will list backrest angles as a number below 100 or above 100. When it is below 100 it is measuring from 90°. For example a 15° backrest, add 90 and find 105° on the protractor. If it is over 100 say 115°, you would just find the number on the protractor.
2) The above will explain why I am sometimes told that the bather slides down in a tub. Since the bottom of the tub will not be angles like the seat of a chair, the more recline, the more sliding possible. The go around for this is a tub that you can put your feet against the tub (foot side or slouch to put your feet on the floor of the tub).

Water Capacity
Another useful measurement is water capacity. Does your water heater have the needed capacity for the tub? Many things affect this; temperature of water supply, temperature the heater is set at, distance of heater from tub and on and on. I found two general rules of thumb: 3/4 and 2/3.
- The capacity of the hot water heater needs to be 3/4 the capacity of the bathtub. If the whirlpool is 100 gallons the heater needs to be 75 gallons.
- In the second opinion the heater should be 2/3 of the capacity of the bathtub. If the whirlpool is 100 gallons the heater needs to be 67 gallons.
- So expect a 100 gallon bathtub to take 67 - 75 gallons of hot water.

Big Enough for Two?
A two-person tub will have a center/side drain and two back slants, so bathers can sit face to face. Or it will be a really wide tub, so two can sit side by side, drain will be at one end. There are few tubs that will break these rules. NOTE: just because the tub is designed for two, doesn't mean two can actually fit. Use the technical for the bath to find out the bathing well size and water height. This will let you know if two can truly fit.

Bathtub Style

Is the tub going to slide between two walls, backed by a third? Is is going to be freestanding in the corner or middle of the room? Are you going to create a tile or wood surround for your tub? There are many ways to incorporate a tub into the bathroom. This guide will help you decide which is the best for you.

Alcove (3 Wall)
Perfect for Tub/Shower Combinations, an alcove requires a rectangular bath placed between three walls. Two features related to alcove installation are tile flanges and front skirts. A skirt hides the underneath of the bathtub in the front. The skirt can be integral to the tub - all one piece. Other skirts are removable or have removable panels to provide access to equipment. There is also the option of creating your own tile or wood front skirt.

A tile flange is used when the walls surrounding the bath are going to be tiled down to the rim of the bath. Perfect for tub/shower combinations.
Tile Flange Drawing

More Information: Alcove Bathtub →

Drop-in (Deck Mount) A drop-in bathtub can be any shape. A deck is created (with an opening in the center) and the bathtub is dropped into the surround. The tub sits on the bathroom floor (not hanging from the rim). The size of the deck is a matter of preference. A lot of pictures will show a wide deck, which can look beautiful, but others don't have the room for a wide tile area. In the second picture (below) the tile decking is kept flush to the bathtub rim. This can be more difficult on a whirlpool bath since the piping takes up room under the rim. Access will be needed for a system tub with a motor or pump. The rectangle tub in the 3rd picture shows a small deck. Easily done due to the wide rim on this bath.

Undermount Perfect for a contemporary bathroom, an undermount bathtub requires a flat rim, any bath shape. The bath edge is under the deck material making the rim of the bath invisible. Make sure to order as an undermount, so the electronic controls will either not be installed or installed in a location that won't interfere with the under mounting. The 1st picture shows an undermount done with stone, the 2nd with wood, stone skirt.
Shop Drop-in & Undermount Bathtub by Size →

Freestanding Freestanding bathtubs are installed away from the wall, even in the middle of the room. Also called a Floor Mount Tub, they have a skirt that surrounds the entire bath. No two freestanding tubs are the same. All are offered as a soaking bath, most are offered with an air system, and very few as a whirlpool. They can be made from acrylic, solid surface, copper or cast iron. We have a separate article discussing How to Choose a Freestanding Bathtub →


What Tub Options are Available?
Options do vary between manufacturers. Here are a few of the standard ones:

A front skirt is usually thought of for use in an alcove installation, but today there are many skirt options offered. First let's discuss the single front skirt. You will hear of a seamed or seamless skirt options. In a seamed skirt there is a small line between the rim of the tub and the skirt
Seam between Tub Rim and Skirt
When seamless - there is not a line
Smooth Front Skirt

Some manufacturers offer a front and side skirt (shown below), or even skirted on all 4 sides making the bath tub freestanding.
Hydro Systems Lacey with 2 Sided Skirt

Bathtub Drain
Bathtubs will come with a hole drilled for the drain (in the bottom of the tub) and one for the overflow (side of the bath). A drain and overflow will be needed to fill these holes. In most cases they come as a set.
Trim Filling Overflow and Drain Hole
Here are some popular drains:
knob on drain cover, flat disc to cover overflow
Lift & Turn Drain | Reach down to the bottom of the tub and lift and turn it to open the drain. The overflow cover is a flat round disc.
Drain cover smooth, overflow cover is a dial to turn
Cable Waste & Overflow | Reach just below the rim to the overflow, turn the overflow (dial) and a cable will open and close the drain at the bottom.
Step on Drain to open or shut
Toe Tap | Step on the drain to lock it shut, step on it again to open it. Overflow is a flat round disc.

Rim Height
The rim stands about 1 3/4" above the tile surround on most drop-in bathtubs. Many companies now offer a slimmer profile - lower rim height option - approx. 9/16" tall.
Standard Rim Height
Standard Rim
Low Profile Rim
Low Profile Rim

Whirlpool, Air or Soaking Bathtub?

There are a lot of tub systems: whirlpool, air, micro bubble, heated soaking, shell warming, stream. Wow! A lot more information than will fit on this page. Please see: Spa Tub → for information on tub systems.
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