Sustainable Hearth Signal vs. E-FX: Which Series Fits Your Project?

Last reviewed: November 3, 2026

The two series people cross-shop most often within the Sustainable Hearth range, and the differences that decide it.

The short answer

Both series offer single-sided, corner, and three-sided installation from the same firebox. The E-FX adds app and voice control and a more developed flame and log presentation. The Signal costs less and is operated by remote only.

If smart-home integration matters, the answer is E-FX. If it does not, the Signal delivers the same architectural look and the same configuration flexibility for meaningfully less. Browse the full Sustainable Hearth collection to compare both alongside the rest of the range.

Where they are the same

It is worth being clear about this, because the shared ground is substantial:

• Both are built-in fireplaces requiring framing and electrical planning.
• Both ship with conversion components allowing single-sided, corner, or three-sided installation.
• Both allow the flame effect to run independently of the heater, so the fireplace works year-round.
• Both offer adjustable flame presentation.

Neither is a compromised version of the other. They are built to different briefs.

Where they differ

Controls

The E-FX Series can be operated by remote, manual keypad, the Sustainable Hearth app, or compatible voice control through Google Home and Amazon Alexa. The Signal Series is remote-operated.

This is the single largest functional difference. If the fireplace is going into a home with an integrated smart-home system, or into a rental or hospitality property where remotes get lost, the E-FX earns its premium on this point alone.

Sizing

The E-FX comes in 40, 52, 60, and 72 inches. The Signal comes in 40, 60, and 80 inches. They overlap at 40 and 60, but only the Signal reaches 80 inches, and only the E-FX offers the intermediate 52- and 72-inch widths.

For a large statement wall, the 80-inch Signal is the widest of the two series.

Flame and media presentation

The E-FX has a more developed flame and log presentation, with illuminated log effects, ember bed lighting, and a low-reflection ultra-high-definition viewing front. The Signal offers adjustable flame height, speed, color, and preset effects in a simpler package.

Heat

The E-FX's hidden heater is rated for supplemental warmth in spaces up to roughly 1,000 square feet. The Signal includes a heater as well. As with every electric fireplace, treat this as supplemental rather than primary heat. For circuit and power planning, see our guide to electric fireplace electrical requirements.

Which one for which project

Choose the E-FX if: the fireplace is the focal point of a primary living space, you want app or voice control, you need a 52- or 72-inch width, or flame and log realism is a priority.

Choose the Signal if: you are working across multiple units and budget scales with the count, you need an 80-inch width, a remote is a perfectly good interface for the space, or the fireplace is one element in a larger design rather than the centerpiece.

In hospitality, office, and multi-unit residential work, the Signal is frequently the better specification rather than the compromise one.

Common mistakes

Assuming three-sided means see-through. Neither series is a see-through fireplace. Three-sided means viewable from the front and both ends within one room. For a fireplace visible from two separate rooms, the Optic 50 is the model in this range built for it.

Choosing on price without checking control requirements. Retrofitting smart control onto a remote-only fireplace is not practical. Decide this before you order.

Framing from the series depth. Corner and three-sided configurations have different requirements from single-sided ones. Build from the model-specific cut sheet. Browse all built-in electric fireplaces if you're still comparing beyond this range.

Frequently asked questions

Does the Sustainable Hearth Signal Series have app control?

No. The Signal Series is operated by its included remote. The E-FX Series supports app and compatible voice control.

What sizes does each series come in?

The E-FX comes in 40, 52, 60, and 72 inches. The Signal comes in 40, 60, and 80 inches.

Can both series be installed as three-sided fireplaces?

Yes. Both ship with conversion components for single-sided, corner, and three-sided installation.

Which series is better for a large feature wall?

The Signal reaches 80 inches, making it the widest single unit between the two. The E-FX tops out at 72 inches.

Is the Signal Series lower quality than the E-FX?

No. It is designed to a different brief, with a simpler control system and flame presentation at a lower price. The configuration flexibility is common to both.

Final thought

Start with the control question, because it is the one you cannot change later. Everything else, such as width, flame depth, and budget, has room to move around it.