Can a hot water cylinder be too big?

Author: Mr. Duncan Robel V  |  Last update: Thursday, January 29, 2026

An oversized water heater heats more hot water than your household needs, which wastes energy.

What happens if your water heater is too big?

Oversized units find it challenging to maintain a steady flow of hot water when the demand varies. If it is too big, the water heater may need help adapting to the flow rate changes, leading to uneven temperatures during simultaneous water usage in different areas of your home.

Is a bigger hot water cylinder better?

If the hot water cylinder is too small, you risk running out of hot water. However, if the cylinder is too big, your energy bills could rise in cost.

Can I replace a 50 gallon water heater with a 40 gallon?

While we recommend 50-gallon heaters for their benefits, we understand that not every space can accommodate the larger size. Our technicians are trained to assess the space available in your home and, when necessary, install a 40-gallon unit if a 50-gallon heater won't fit.

Is a 75 gallon water heater too big?

Typically, the rule-of-thumb is that you want a 40 gallon tank for 1 to 4 people, a 50 gallon tank for 4 to 6 people, and a 50 gallon high recovery or 75 gallon tank for 6 to 8 people.

What Size Water Heater Do I Need? Solved! | Water Heaters 101

Should I oversize my water heater?

Making sure you have a properly sized water heater is very important. If your water heater is too small, your home won't have enough hot water to meet demand, which is an obvious inconvenience, and overloading the unit may cause premature wear and tear. There's no benefit to oversizing a tankless water heater.

What size water heater do I need for a 75 gallon tub?

If you have an oversized whirlpool bath or other large tub. As a rule of thumb, the water heater tank capacity should be 100% of your bathtub capacity (example: 75-gallon tub / 75-gallon water heater).

How much should it cost to replace a 50 gallon gas hot water heater?

Gas water heaters typically range from $1,100 to $4,000 for complete professional replacement depending on your area and complexity of installation.

How many showers can you take with a 40-gallon water heater?

For instance, a typical shower uses about 10 gallons of hot water. So, if you have a 40-gallon hot water tank, you should be able to get four average-length showers out of your hot water tank. This also depends on how much hot water you use for other things.

Is there a big difference between a 40-gallon and 50 gallon water heater?

If you are on a budget, a 40-gallon may be the better option for you. Water Heater Efficiency: When it comes to efficiency, a 50-gallon water heater is going to be more efficient than a 40-gallon water heater. This is because it will have a lower recovery time, which means it will take less time to heat the water.

What is the lifespan of a hot water cylinder?

On average, an electric hot water heater should last around 10 to 15 years. Most manufacturers' warranties are for 10 years. So if you've recently purchased a home with a water tank that's close to 10 years old, you will probably want to budget in replacing it sometime soon.

Will a bigger water heater increase water pressure?

Upgrade to a bigger Water Heater: If your existing water heater isn't large enough to provide the hot water requirements of your family upgrading to a higher capacity model will guarantee plenty of hot water with increased pressure.

What is the most common size for a domestic hot water cylinder?

Domestic cylinders are typically available in 6 sizes from 120 to 300 litres. If we take the most “standard” installation, a 4 bedroom house with gas central heating and a bathroom and ensuite shower, a 180 litre would typically be suitable.

How many bathrooms can a 50 gallon water heater handle?

It is very common to find a 50 gallon water heater in a 3 bedroom/3 bathroom home. This is not only because the uniform plumbing code regulates the minimum capacity required in homes based on bedroom and bathroom size, but also because a 50 gallon capacity unit will appropriately serve a to 3 bed/3 bath residence.

Is Rheem or AO Smith a better water heater?

If you're looking for a reliable, efficient, and cost-effective water heater, Rheemhas the edge over A.O. Smith. With superior energy efficiency, longer warranties, and better overall performance, Rheem units are designed to meet the needs of modern homeowners.

Why is the bottom of my water heater full of water?

Water Leaking From The Bottom

If you notice water leaking from near the base of your water heater, it could be an issue with the drain valve. The drain valve is designed to empty the water tank when needed, such as during maintenance. Solution: Inspect the drain valve for corrosion and replace.

How much hot water does a 10 minute shower use?

Generally, taking a shower uses less water than a full bath. A standard showerhead flows at a rate of 2.5 gallons per minute . This means that a ten-minute shower only uses 25 gallons of water.

Is a 50 gallon water heater too big?

A small (50- to 60-gallon) storage tank is usually sufficient for one to two three people. A medium (80-gallon) storage tank works well for three to four people. A large tank is appropriate for four to six people.

Should I get 40 or 60 gallons water heater?

Forty-gallon water heaters are perfect for homes with one or two people or those living in smaller spaces. On the other hand, 60-gallon water heaters are suited for larger families (of three or more) or if you have a large tub or hot tub.

How long does it take a plumber to replace a gas water heater?

Water Heater Installation Process. Once you decide to (or are forced to) replace your current water heater, there are a few decisions you need to make to get the process started. If there are no issues or complications, a licensed plumber should be able to complete the process in 2-3 hours.

Can I replace 40 gallon water heater with 50?

The diameter of the 50 gallon unit is only 2” bigger than the 40 gallon model, and the other dimensions and venting requirements are identical. No venting or gas piping revisions are needed going up from one size to the other.

How much is labor to install a hot water heater?

In general, plumbers cost $45 to $200 per hour, while electricians cost $50 to $100 per hour. Expect the following average price ranges for labor alone: Replacing a tank-style water heater: $150–$450. Replacing a tankless water heater: $600–$1,850.

Who makes the best water heaters?

These are the three water heater brands ranked in the order of our preference:
  • American Standard.
  • Bradford White.
  • Rheem.

Will a 40-gallon water heater fill a bathtub?

A rule of thumb is you'll need a water heater tank that's at least 2/3 the size of your bath tub. Most walk-in tubs range in capacity from 42 to 60 gallons. So, for a 60 gallon walk-in tub, you'd need at least a 40-gallon water heater.

Should I buy a 50 gallon or 75 gallon water heater?

A 50 gallon water heater is sufficient for a household of 3 to 4 people. If you have over 5 people in your home, you may require a 75 gallon hot water heater.

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