Screw-In vs. Bolt-In Water Heater Elements: What's the Difference
Electric water heater elements mount into the tank one of two ways — screw-in or bolt-in (flange) — and the two styles are not interchangeable. Knowing which one your tank uses is the first thing to confirm before ordering a replacement.
Screw-in elements
A screw-in element threads directly into a boss on the tank, like a large bolt — most commonly 1” or 1-1/2” NPT thread. It’s removed and installed with a dedicated element wrench. This is the most common style on residential electric water heaters.
Bolt-in (flange) elements
A bolt-in element mounts on a circular flange, sealed against the tank opening with a gasket and secured with several bolts around the flange’s edge. This style shows up more often on some commercial tanks and certain older or specific residential models.
How to tell which one you have
Look at the base of the old element:
- A round threaded shaft = screw-in.
- A flat plate with bolt holes and a gasket = bolt-in (flange).
If you’re not sure, a photo of the old element is the fastest way for us to confirm.
Why it matters
Beyond the mounting style, a replacement also has to match the tank’s wattage and voltage — an element with the wrong wattage will heat too slowly or trip the breaker, and the wrong voltage changes the heat output entirely (see our 240V vs. 208V guide for why that matters). The mounting style, wattage, and voltage all have to line up together.
Getting the right replacement
Not sure which failed, or want to confirm before you order? Our guide on diagnosing which water heater element failed walks through the symptoms and testing. Once you know what you need, send us your tank’s brand and model, or a photo of the old element, and we’ll match it on our water heater elements page — get a quote and we’ll ship it across Canada.
Frequently asked questions
- Can I put a screw-in element in a bolt-in tank, or vice versa?
- No — the two mounting styles aren't interchangeable. A screw-in element needs a threaded boss on the tank; a bolt-in element needs a flange opening with matching bolt holes. Check which one your tank has before ordering.
- Which style is more common?
- Screw-in is the most common style on residential electric water heaters. Bolt-in (flange) elements show up more on some commercial tanks and certain older or specific models.
- Does the element brand have to match my tank's brand?
- Not necessarily. Many tanks use industry-standard thread and flange patterns, so a compatible wattage and voltage from another brand can fit. We confirm compatibility before you order rather than guess.
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Need a replacement element? We ship across Canada and build custom elements for hard-to-find equipment.