Intermatic WH21 Electric Water Heater Timer - Schedule Hot Water

In this review the Intermatic WH21 Electric Water Heater Timer is presented as a straightforward, dependable solution for homeowners who want to schedule hot water use and reduce energy waste. Designed for 208 to 277V residential electric hot water heater applications, this timer's single biggest advantage is its ability to automatically switch the heater on during high-use periods and off during low-use periods, with up to 12 on/off settings per day, making it a practical choice for anyone looking to cut electricity costs without complex programming.

Key Features

• Automatic scheduling: The timer repeats a preset daily schedule so hot water is available when needed without manual intervention.
• Manual override: A push button lets the user turn the water heater on or off ahead of schedule and the unit will resume the program at the next scheduled operation.
• High switching capacity: The single pole/single throw contact supports up to 25 amps (6250 watts) to handle most residential electric water heaters within its voltage range.
• Multiple operations per day: Up to 12 on/off settings per day give flexibility to match household routines and peak usage times.
• Durable construction: Steel material and a NEMA 1 enclosure provide a robust, code-friendly package for indoor installation.
• Certified safety approvals: UL and CSA approvals for Canada and US offer reassurance about electrical safety and compliance.

Who It's For

The Intermatic WH21 is suited to homeowners with electric hot water heaters on 208 to 240 VAC who want a simple mechanical timer to lower standby and off-peak energy use. It is well matched to families with predictable daily usage windows or to households on time-of-use utility plans where shifting demand can save money.

Those who should look elsewhere include owners of gas or tankless water heaters, or anyone who needs remote app control or intricate digital scheduling features; this is a mechanical time switch that favors reliability and simplicity over connected smart controls.

Pros & Cons

Pros

• Easy to install for typical residential electric water heaters and praised for straightforward operation by users.
• Helpful money-saving potential by turning the heater off during low use periods and on when needed.
• Solid build and recognized safety approvals that match residential electrical requirements.
• Manual override provides convenient short-term control without reprogramming the schedule.

Cons

• Mechanical timer limits advanced scheduling options and remote control compared with digital smart timers.
• Some users report occasional timing drift or long-term reliability concerns with mechanical components.

Specifications

Brand	Intermatic
Model	WH21 Electric Water Heater Timer
Voltage rating	208 to 277 VAC
Current / Capacity	25 ampere (6,250 watts)
Frequency	60 Hz
Operations per day	Up to 12 on/off settings
Enclosure / Material	NEMA 1 enclosure, steel material

Our Verdict

The Intermatic WH21 is a practical, value-oriented timer for residential electric hot water heaters that delivers reliable scheduling, approved safety credentials, and potential energy savings. Buyers who want a low-complexity, durable mechanical solution to reduce standby heating costs will find it a good match; those wanting smart connectivity should consider alternatives.

Frequently Asked Questions

What voltage does this timer support?
The WH21 is rated for 208 to 277 VAC operation and is intended for 208 to 240 VAC residential electric hot water heater applications.

How many on/off settings can be programmed each day?
The timer allows up to 12 on/off operations per day, providing flexibility to match household usage patterns.

Is there a manual override?
Yes, a push-button manual override lets you turn the water heater on or off ahead of the schedule and the unit resumes the preset program at the next scheduled operation.