It is no fun to start the bath with warm water and then shiver when the water cools down. After all, a pleasant bath is all about that right “warm” temperature.
A decent soak in the bathtub should last about 15 to 20 minutes, but sometimes the water gets too cold even after a couple of minutes.
Although hot water losing heat over time is only logical, there are ways to keep your bathwater warm long enough to enjoy a relaxing bath.
Here’s what you need to know about keeping your bathwater warm.

Why Isn’t the Bath Water Warm Enough?
Generally, you want to soak in bathwater that’s between 90 to 105 degrees. There are several reasons why bathwater can’t seem to get warm enough:
- Your bathtub could have poor insulation. Insufficient insulation can cause the bathwater to lose heat more quickly.
- Inadequate insulation of your bathroom walls. When it’s too cold outside, like during winter, that could lead to a chilly bathroom, ultimately affecting the water temperature in the bathtub.
- Your water heater could be a bit too small. You need to pick a heater depending on the size of your bathtub or the amount of hot water you need. An insufficient water heater will always be running out of hot water to fill your tub.
- Your bathroom could just be chilly. Common hard surfaces in bathrooms like ceramic, glass, and metal take the heat out of the air, and it’s up to the hot bath water to try to warm the room. Thus, your bath water loses heat much faster.
6 Ways to Keep the Bath Water Warm Longer
Now that you know what causes bathtub water to not stay warm long enough, it’s time to list the solutions – the best ways to keep your bathwater warm.
1. Keep the Bathroom Door Closed
There was this old saying that goes, “never leave the door open while taking a bath,” and in this case, it’s absolutely right. It is not only an issue of privacy but of keeping the bath water warmer for longer periods of time.
You want the steam coming out of your bath water to be contained in the bathroom, warming the space in the process. Closing the bathroom door will keep the warm air from escaping. If your bathtub comes with a shower curtain, consider closing that as well.
2. Preheat the Bath to a Higher Temperature
Water loses heat, and it’s just the way things are, especially while filling the tub. Your bathtub has a cold surface, and as you fill it, the tub will absorb some of the heat from the bathwater. That’s one of the reasons why your once warm water has turned less warm as you get in. The quickest way to deal with this problem is to preheat the cold tub.
Instead of filling up the tub with your desired “warm” temperature, run the water hotter than you normally would. If it’s too hot for your liking afterward, you can simply adjust it by adding cold water to get the water temperature you prefer. After all, it’s easier to make the bathwater colder than it is to make it hotter.
3. Add a Couple of Hot Stones
While brainstorming ways to keep the bathwater warm for a long-lasting experience, have you considered adding hot stones?
Heat-retaining stones are usually made of volcanic rocks called basalt that you can add to the tub, and they can extend your warm relaxing bath. Heat them up to a comfortable temperature and place them in your bathtub, and they will keep your bathtub’s water warm for the entirety of your bath. You might need a couple of hot stones, depending on how large your tub is.
4. Use a Space Heater
Another trick to keep your bathwater warm is to get a space heater. It’s not going to heat the bathwater directly, but indirectly it will warm up the bathroom itself. This tip is especially useful if you have an especially cold bathroom or if your tub has poor insulation.
This way, there is no cool air taking heat from the bathwater, allowing it to stay warm for much longer. But always be careful when using electrical appliances in the bathroom, especially near the tub.
As a safety rule, consider running the space heater before filling the tub. Once the bathroom is warm enough, unplug the heater, and you can then fill the tub and enjoy a nice, hot bath. A warmer room will allow the bathwater to retain heat for longer.
5. Switch to a Tankless Water Heater
If your existing water heater doesn’t have enough hot water capacity to fill the tub, switch to a tankless water heater. It heats up water on demand, giving you unlimited hot water to fill your bathtub.
Not to mention, tankless water heaters are energy-efficient since it only heats water as you need it. It’s the best option for larger bathtubs and if you use a lot of hot water.
6. Take Bubble Baths
Besides warm baths, bubble baths are one of the most enjoyable and luxurious bath experiences you can have at home. If you love both, there’s no reason why you couldn’t do both at the same time. In fact, bubbles can even retain the warmth of your bath water for much longer.
Bubbles act as a barrier on the surface of the water, preserving the water temperature and keeping the cooler air of the bathroom from replacing the steam.
Which Is the Best Bathtub for Keeping Bath Water Warm?
Not all bathtubs are the same. And while they vary in shapes and sizes, they are made of different materials too. The tub’s material plays a huge role in how effective it is in retaining heat and keeping the bathwater warm.
Common bathtub materials include acrylic, copper, cast iron, and stone. Acrylic bathtubs are reasonably priced and have good insulation, keeping the bathwater warm for an extended period.
Stone and metal bathtubs are also great heat conductors, which are excellent at trapping heat, so the bathwater stays warmer longer. The only disadvantage is that they usually cost more.
More Tips for Keeping the Bathroom Warmer
Keeping the chill from your bathroom goes a long way in keeping the bathwater warm so you can enjoy your bath longer. If you have an especially chilly bathroom, these tips will help you out.
- Besides the doors, close the windows, curtains, and blinds while you take a warm bath, so the chilly air stays out.
- If you have a cold bathroom floor, consider covering it with fluffy bath mats.