how long can you shower with a 40-gallon water heater?When you’re buying a new water heater, you should consider that its size will limit the length of shower that you can have. Anyone who has taken a hot shower knows how frustrating it is to lose heat midway through. So, it is important to select the right-sized water heater for your showering needs. How long can you shower with a 40-gallon water heater? Unfortunately, the answer isn’t too straightforward.

How Long Can I Shower?

While you will find time estimates online, ranging from two full showers to one fifteen-minute shower with a 40-gallon water heater, they are not strictly accurate. You need more information to know how long you’ll be able to shower with any size water heater.

First, flow rate. How much water will come out of your showerhead when you run it? Showerheads range from the legal maximum (in most places) of 2.5 gallons per minute to a very modest and water-conserving 1.5 gallons per minute. Your most basic calculation is dividing your water heater’s capacity by your shower head flow rate. The low-flow gets you 26 minutes of hot water. The high flow gets you only 16.

Of course, this isn’t exactly right either. Your showerhead mixes in some cold water with the hot, and more if you like your showers on the colder side. So, those who take colder showers will be able to take longer showers.

Also, water heaters won’t be able to deliver the same level of heat as they approach empty. Once roughly 75% of their capacity has been used, they start to deliver colder water. However, the heater will also be actively heating up more water as it runs. A gas heater will be able to recover faster than an electric heater and will therefore last longer.

So, take your basic calculation of 40-gallons divided by your shower head flow and modify it. Add a bit of time if you and your family like colder showers and if you have a gas heater. If you like hot showers and have an electric heater, then your showers won’t have much leeway beyond that basic calculation. Don’t forget that it will also be longer for your tank to fill, so other family members will need to wait longer to shower.

Should I Choose a Larger Water Heater?

If you’ve taken the time to calculate the precise amount of time that you will be able to shower with a 40-gallon tank, it’s safe to say this issue is important to you. Maybe you like your showers extra hot and long, or you have a large family. Either way, you might consider getting a larger water heater and getting a shower head with reduced flow. Both will enable you to have the kind of shower time you need without sacrificing temperature.

There are 50-gallon water heaters to provide a bit of a boost to your time and 80-gallon tanks if you suspect that you’ll need much more shower time.

Of course, the other option is to invest in a tankless water heater. Tankless water heaters provide a nonstop supply of hot water on demand, so you could shower for hours without water running cold (if you really, really wanted to!)

At Simpson Plumbing, we install Navien tankless water heaters because they offer the best balance of performance and affordability. Learn more about our tankless water heater services here or speak with one of our team members to get started.