What Size Water Heater Do You Need?

Selecting the right-sized water heater can make a big difference in how well it meets your household’s needs while running efficiently. There is naturally a greater demand for hot water in households with many people. If you want a tank-style water heater, keep in mind that it has a limited capacity to deliver hot water at any given moment. Whether you are considering replacing your old unit with a new tank or tankless model, it is wise to consult a professional plumber.

Choosing the Right Size Water Heater in Nevada

Tank Water Heaters

These heat water stored in a tank and keep it warm until it is used. The size of a tank is determined by its capacity, measured in gallons. A good rule of thumb is to consider the number of people in your household for your water heater size calculator:

1-2 people: 30-40 gallons
2-3 people: 40-50 gallons
3-4 people: 50-60 gallons
5+ people: 60-80 gallons

Also, calculate the number of gallons your household uses during the busiest hour of the day. This can be determined by looking at your family’s habits. For example, if multiple showers, laundry, and dishwashing happen simultaneously, your peak-hour demand will be high. The First Hour Rating (FHR) measurement tells you how many gallons of hot water the tank can supply per hour at peak usage. You should look for a unit with an FHR that meets or exceeds your calculated peak-hour demand.

You can use this water heater capacity guide to help you determine your peak hour usage and calculate the FHR:

Shower: 16-20 gallons (for an 8-10-minute shower).
Bath: 25-40 gallons per bath.
Toilet Flush: 1.28 to 1.6 gallons per flush.
Hand/Face Washing: 0.5 gallons per minute.
Dishwasher: 4-6 gallons per load.
Clothes Washer: 15-25 gallons per load.

The “Recovery Rate” is another thing you should look for before buying a heater. It tells you how quickly it can reheat water once the tank starts to deplete. A higher recovery rate is beneficial if your house consumes large amounts of hot water in a short period.

Tankless Water Heaters

A tankless or on-demand heater heats water directly but it does have a limit on the flow rate of hot water at a time. The size of this system is based on the flow rate, measured in gallons per minute (GPM), and the temperature rise needed (difference between incoming and desired hot water temperatures).

Estimate your maximum simultaneous water usage (like showering and running the dishwasher at the same time). Typical shower flow rates are around 2-3 GPM, and kitchen faucets are about 1-1.5 GPM. Consider showers, faucets, washing machines, and dishwashers. For example, if you anticipate needing two showers (2-3 GPM each) and a kitchen faucet (1-1.5 GPM) simultaneously, you would need a system that can handle at least 6 GPM.

Then measure the difference between the ground water temperature at your location and your desired output temperature (around 120°F). If your incoming water is 50°F and you need it to be 120°F, you will need a temperature rise of 70°F.

If multiple high-demand fixtures are used at once, consider a model designed for higher GPM capacity. For large homes in Nevada, sometimes installing more than one tankless water heater, or using separate heaters for different areas (one for bathrooms and another for the kitchen), can be more efficient than one large unit.

Gas vs. Electric Water Heaters

Both gas and electric heaters can be tank or tankless, but they differ in efficiency. Gas Heaters have higher recovery rates, i.e., they heat a larger volume of water faster. So, if you want a storage tank heater, you could choose a slightly smaller gas-operated model if your peak water usage is concentrated in short bursts.

Electric Heaters generally have lower recovery rates, so you might need a larger tank to get a continuous supply during peak usage times. In case of tankless models, while electric units can supply a consistent temperature rise, their flow rate might be lower compared to gas; they might struggle under simultaneous high demand (e.g., shower plus dishwasher).

If you have a family of four that frequently uses hot water for showers, laundry, and kitchen needs at the same time, get a 50-60 gallon gas tank heater for quick recovery after the hot water is depleted, or a 60-80 gallon electric tank heater if you prefer a model that might take a bit longer to recover but is simpler to install.

However, if a tankless system sounds better, choose a gas model that handles a flow rate of about 7-9 GPM if you live in a colder climate to ensure it meets demand even when inlet water is very cold. An electric model should be considered only if your maximum flow demand does not exceed 3-4 GPM (typical for smaller households or milder climates).

DIY vs. Professional Water Heater Installation

The most apparent benefit of DIY installation is saving on costs. However, do not forget to weigh it against the obvious cons: installing a heating system requires a knowledge of electrical wiring or gas lines, both of which are dangerous if not handled properly.

HVAC systems, including heaters, need to be installed in compliance with your local building codes. Unless you are an expert in safety standards regarding earthquake strapping, venting, etc., this one is going to be a challenge. A lot of manufacturers in Nevada require professional installation for the warranty to be valid; installing it yourself will void it.

Professional plumbers not only have the necessary experience, skills and tools to do the job – they know how to do the job right and fast. At Active Plumbing & Air Conditioning, an average water heater installation in Nevada takes our team 2-4 hours (depending on electric vs. gas) only. This includes removing the old unit, properly disposing of it, installing the new one, checking for leaks, and handling any unexpected issues that might arise.

Trust Active Plumbing & Air Conditioning for Water Heater Installation in Nevada

We have been the go-to plumbing company in Las Vegas and surrounding areas in Nevada for over 30 years. If you need your existing water heater repaired or replaced, you want some guidance on how to determine water heater size, or you want to know more about the difference between traditional water heaters and tankless water heaters – call at (702) 553-1171 or send us a message.