Gas vs. electric water heaters: A pro’s guide

As a pro, every water heater job comes down to three things: how fast you can get it installed, how well it will perform for the customer, and what kind of service calls it’ll create down the road. Getting these decisions right protects your time and your reputation.

Installation

Electric water heaters are typically the most predictable installs. The process is usually limited to water and electrical connections which allows contractors to move quickly with installations, and in some cases, replacements. Wiring can be a potential point of friction as the National Electrical Code (NEC) requires that wiring be protected from physical damage by some form of conduit or tubing. While that’s not specifically an electric water heater wiring code, it’s still something to consider during installation.

By comparison, gas water heaters, such as these from Rheem, require a few more steps, and a look at a gas water heater venting diagram will show that. In addition to plumbing connections, installers must verify gas supply, ensure proper venting, and confirm air combustion requirements. Because gas water heater venting is so precise — even minor issues can extend the installation process.

Performance

At its best, a high-efficiency electric water heater provides consistent heating, but it’s limited by element output, and thus more susceptible to periods without hot water. Once the tank is depleted, recovery is slower, which can obviously become quite noticeable in higher-demand households.

A high-efficiency gas water heater generally handles peak demand more effectively. For instance, take a Bradford White gas water heater: you’ll find it operates at higher BTU inputs, which allows for faster recovery and better performance under simultaneous use than, for the sake of comparison, a Bradford White electric water heater.

Parts and components

One of the most important differences for contractors is the type and number of components inside each system. This directly affects troubleshooting time, truck stock, and repair margins.

Electric units, like these from A. O. Smith, have components that are widely standardized and easy to access. Most failures are isolated to one part, making diagnosis straightforward — and because these essentials are regularly in stock, you can utilize same-day pickup from your local Ferguson to finish the repair.

Gas units, with their full combustion systems, create more billable service opportunities over their lifespan. From cleaning a flame sensor clogged by dust to troubleshooting an ignition system, these callbacks can be a reliable source of revenue for your service agreements.

Service opportunities

Electric water heaters tend to generate fewer service calls. When issues arise, they are usually limited to element or thermostat failure — repairs that are quick and relatively low-cost.

Gas water heaters produce a wider range of service scenarios. Burner issues, ignition failures, and venting problems can all lead to loss of hot water, often requiring more time to diagnose and repair.

Now that you’re equipped with the info, equip the tools for your next contract by shopping at Ferguson. We host an inventory of electric and gas water heaters, parts, and components from Bradford White, Rheem, A. O. Smith and other cutting-edge, industry-leading brands so that you can shop with convenience and provide service with confidence.

FAQs

How long does a water heater last?

Accounting for key factors like usage, maintenance, installation integrity, and water quality — a standard water heater, gas or electric, typically is expected to last anywhere from 8 to 15 years, on average.

How does sediment buildup impact gas vs electric water heater performance?

In electric units, sediment accumulates around the lower heating element. This can lead to element burnout, but the issue is typically resolved with a straightforward replacement, such as a Bradford White hydro jet system or a self-cleaning dip tube.

In gas units, sediment settles at the bottom of the tank, directly above the burner. This reduces heat transfer and can cause overheating, noise, and efficiency loss. These problems are often less isolated and may require more involved maintenance.

What are the sizing and installation considerations when switching from gas to electric water heaters? From electric to gas?

When switching from gas to electric, you’re going from a fuel-based system to an electrical one, so the key consideration is whether your customer’s electrical panel can handle the added load as electric water heaters have a high current demand. A panel upgrade and additional breaker space may be needed. Also, because electric units heat water more slowly, your customer may also need a larger tank size to maintain hot water supply.

When switching from electric to gas, you’re moving from electrical demand to fuel demand, so the focus is on the gas line, and making this switch often requires a larger gas line due to high BTU demand. Installation is more complex because you’ll also need proper venting, and possibly a new gas connection if one isn’t already available. However, gas units typically recover faster, so you may be able to use a smaller tank.

How do I choose the right replacement strategy for my customer?

The best approach depends on the customer's immediate needs and long-term hot water demands.

For instance, imagine your customer's 15-year-old electric tank failed — and they need hot water now. An electric-to-electric swap with a model that both fits the existing space and is compatible with their electrical circuit is your fastest path to a happy customer.

Maybe a family of five is constantly running out of hot water. For this level of demand, a high-recovery gas model or a new tankless unit will prevent those “no hot water” calls.

Thankfully, Ferguson hosts options from Bradford White, Rheem, A. O. Smith, and other top brands that deliver the performance needed to prevent callbacks.