Electric Water Heater Thermostat Kit - Upper KST203 & Lower KST200

In this review the Electric Water Heater Thermostat Kit is evaluated as a straightforward replacement solution for dual element residential water heaters. The kit bundles a KST203 upper thermostat and a KST200 lower thermostat, both UL certified and adjustable from 90F to 150F, which makes it attractive for homeowners and technicians who need reliable, quick-acting temperature control without fuss. The single biggest reason to buy is compatibility: these thermostats are built in a Thermo-O-Disc style and are interchangeable with common Apcom-type controls, so they fit a wide range of makes and models.

Key Features

• High quality contacts: The metal contact construction enables faster switching and longer service life compared with lower-grade parts.
• Adjustable temperature range: Controls water temperature from 90F to 150F to suit household preferences and safety needs.
• UL certified: Safety certification gives confidence that the thermostats meet recognized electrical and performance standards.
• Wide compatibility: Designed to work with most dual element water heaters from many common brands, reducing the need to source model-specific parts.
• Built-in safety switch: An internal safety cutoff helps prevent overheating, adding a layer of protection for the tank and occupants.
• Complete pair: The kit includes both the upper (KST203) and lower (KST200) thermostats needed for most dual element replacements.

Who It's For

The kit is ideal for homeowners, plumbers, and maintenance technicians replacing thermostats on dual element electric water heaters from brands like GE, Whirlpool, Rheem, Bradford White and many Apcom-compatible models. Its UL certification and adjustable range make it suitable for households that want reliable temperature control and a safety cutoff feature.

It is not the right choice for single element heaters, specialized commercial systems that require proprietary controls, or installations that demand smart/HomeKit-enabled temperature management. Buyers needing an exact OEM match should verify interchangeability before purchase.

Pros & Cons

Pros

• Includes both upper and lower thermostats so users can complete a dual element replacement in one purchase.
• UL certification and built-in safety switch provide an added margin of safety during operation.
• Adjustable 90F-150F range covers typical residential hot water needs and user preference.
• Interchangeable Thermo-O-Disc/Apcom style increases compatibility with many heater brands.

Cons

• Not suitable for single element tanks or heaters that require a different thermostat form factor.
• Some installers may prefer OEM-branded controls for a guaranteed model-specific fit.

Specifications

Our Verdict

The Electric Water Heater Thermostat Kit offers solid, no-frills value for anyone replacing thermostats on dual element residential water heaters. With a complete upper and lower pair, UL certification, and a practical 90F-150F adjustment range, it suits most home repair jobs and routine maintenance. Professionals and DIYers who need broad compatibility and a built-in safety switch will find it a dependable, cost-effective option.

Frequently Asked Questions

Are both thermostats included?
Yes, the package includes one KST200 lower thermostat and one KST203 upper thermostat.

Will these fit my water heater?
They are Thermo-O-Disc/Apcom style and compatible with many dual element models, but verify physical fit and mounting type against your heater before buying.

What temperature range can I set?
The thermostats adjust from 90F to 150F (32C to 66C) and include a built-in safety switch to help prevent overheating.