Dimplex markets the Ignite Aspire as "a simple, environmentally friendly replacement to natural gas units," sized in four widths that match typical gas fireplace openings. If you have a gas firebox you have stopped using — or want to stop using — that is an appealing pitch.
It is also mostly true. But there are two things about this swap that nobody tells you until the wall is open, and both can stop the project cold. One is heat. The other is height.
The honest headline: you will lose most of your heat
This is the part to settle before anything else, because it decides whether you should do this at all.
| Appliance | Heat output |
|---|---|
| Kingsman HB4224 42" gas | 24,000 BTU |
| Kingsman ZCV39 gas, ceramic glass | 28,000 BTU |
| Kingsman ZCVRB60 60" linear gas | 35,000 BTU |
| Dimplex Ignite Aspire, 120V | 5,118 BTU |
| Dimplex Ignite Aspire, 240V | 8,530 BTU |
Wired at 120V, an Aspire produces roughly one fifth the heat of a mid-size gas fireplace. Even at 240V it is under a third. Dimplex rates the Comfort$aver system for supplemental heat in areas up to 1,000 square feet at 240V, and that word — supplemental — is doing real work.
So: if your gas fireplace is meaningfully heating a room and you replace it with electric, you will notice. Plan on your central heating covering the difference.
If, on the other hand, your gas fireplace is essentially decorative — run a few evenings a month for atmosphere, with the furnace doing the actual work — then the heat difference is close to irrelevant and everything else about this swap is an upgrade.
The one that surprises builders: the Aspire is taller
Dimplex sizes the Aspire to match gas fireplace widths. Nobody mentions the heights, and this is where straight-swap plans fall apart.
| Unit | Rough opening (W x H) |
|---|---|
| Kingsman HB4224 42" gas (louvered) | 42 3/8" x 37 1/4" |
| Dimplex Aspire ASP42 | 42 3/4" x 47" |
| Kingsman ZCV3622 36" gas | 36 3/8" x 37 1/4" |
| Dimplex Aspire ASP36 | 36 3/4" x 44" |
The widths line up within about half an inch. The heights do not — the Aspire needs roughly seven to ten inches more vertical opening. It is a portrait-format firebox with a deeper viewing area, and that geometry is the whole point of how it looks.
What that means practically: replacing a 42-inch gas unit with an ASP42 is not a drop-in. Someone has to open the wall above the existing opening and reframe the header. That is drywall, framing, and refinishing work — not catastrophic, but it belongs in your budget and your contractor's scope from day one, not discovered halfway through.
Full Aspire framing dimensions:
| Model | Rough opening (W x H x D) | Best matched to |
|---|---|---|
| ASP30 | 30 3/4" x 38" x 18" | Small gas fireboxes, bedrooms |
| ASP36 | 36 3/4" x 44" x 18" | 36" gas fireplaces |
| ASP42 | 42 3/4" x 47" x 18" | 42" gas fireplaces |
| ASP48 | 48 3/4" x 50" x 18" | Large fireboxes, feature walls |
Dimensions per Dimplex published architectural specifications. Confirm against the current installation manual before framing.
Decommissioning the gas: not a DIY step
Before the old firebox comes out, the gas supply has to be properly shut off and capped. This is licensed-trade work, full stop — a capped line that is not capped correctly is a gas leak in a wall cavity.
Your installer will also need to deal with the existing venting. A direct-vent gas fireplace has a co-axial pipe running to an exterior wall or roof. The Aspire needs none of it, which leaves you with a redundant penetration in your building envelope that has to be sealed, insulated, and made weathertight from the outside. Skipping this is how you end up with a draft, a moisture path, or both.
Both jobs are straightforward for the right trades. Neither is optional.
The electrical decision: 120V or 240V
This is the choice that determines whether the swap is easy or involved.
120V hardwired gives you 5,118 BTU. If a suitable circuit already runs near the fireplace, this is the simple path. Dimplex also offers an optional 120V plug kit, which turns the job into something a remodel or condo can accommodate without opening more wall than necessary.
240V hardwired gives you 8,530 BTU — a 67% increase — and is what Dimplex's 1,000 square foot supplemental rating assumes. It also means a dedicated 240V circuit run from your panel by a licensed electrician, with panel capacity to spare.
Standard installation for the Aspire is hardwired 120/240V. Decide early, because it changes both the electrician's scope and the heat you end up with. If you are giving up a 24,000 BTU gas appliance, the extra 3,400 BTU from 240V is worth having.
What you gain
Set against the heat loss and the framing work, the case for electric is real:
- No venting, no combustion, no gas. No annual service on a gas valve, no pilot, no carbon monoxide considerations.
- Flame without heat, year round. The Aspire runs its flame effect independently of the heater — the fireplace is alive in July.
- Installation flexibility a gas unit cannot match. Front-facing, left corner, right corner, or bay. Multi-sided configurations need the optional Convertible Trim Kit.
- Genuine control. Nine flame colour themes, three ember bed themes, adjustable brightness and flame speed, three crackling sound options, plus the Flame Connect app, a wall-mounted remote, and an onboard panel.
- Realism that has moved on. Dynamic-Fire flame effect, quick-connect Rhythmic logs with inner glow that pulse in time with the flame, tumbled glass embers, and a mirrored glass backer for depth.
- Five-year parts and service warranty.
Should you do it?
Good reasons to switch: your gas fireplace is decorative rather than a heat source; you want off gas; the unit is old and a repair or replacement quote has arrived; you want a flame you can run in summer; you are already opening the wall for other work.
Reasons to think twice: the fireplace is doing real heating work; you are in a cold climate relying on it during outages (a millivolt gas fireplace runs without power — an electric one does not); or you were hoping for a drop-in swap with no framing.
If that last point is the sticking place, there is a middle path worth knowing about: replacing an old gas fireplace with a current gas fireplace. A modern Kingsman ZCV39 in ceramic glass reaches 28,000 BTU at roughly 66% efficiency, and if your existing opening and venting suit it, the framing work may be far less. We would rather tell you that than sell you the wrong thing.
Send us your existing opening dimensions
Width, height, and depth of your current gas firebox opening, plus how much wall you have above it. We will tell you which Aspire fits, how much reframing it needs, and whether electric is the right call for your room at all.
Call +1 (877) 879-9191 (Mon–Fri, 8:00 AM–5:00 PM ET) or email support@lumiflares.com.
Frequently asked questions
Can I replace a gas fireplace with an electric one?
Yes. The gas supply must be shut off and capped by a licensed professional, the old firebox removed, the redundant vent penetration sealed, and an electrical supply run. The Dimplex Ignite Aspire is designed for exactly this, in four widths matching common gas fireplace sizes.
Will an electric fireplace heat as well as my gas fireplace?
No. An Aspire produces 5,118 BTU at 120V or 8,530 BTU at 240V, against 24,000–35,000 BTU for typical gas fireplaces. Treat electric as supplemental heat and expect your central heating to carry more of the load.
Will an Aspire fit my existing gas fireplace opening?
The width probably matches; the height probably does not. An ASP42 needs a 47-inch-tall opening where a 42-inch gas fireplace needs about 37 1/4 inches. Expect to reframe the header.
Do I need 240V?
Not necessarily, but it produces 67% more heat — 8,530 BTU versus 5,118 — and is what Dimplex's 1,000 square foot rating assumes. Standard installation is hardwired 120/240V, with an optional 120V plug kit available.
What happens to the old gas vent pipe?
It becomes redundant. The exterior penetration must be sealed, insulated, and weatherproofed properly, or you have created a draft and a moisture path into your wall.
Does an electric fireplace work during a power outage?
No. This is a genuine trade-off. Kingsman gas fireplaces with Millivolt or IPI valve systems operate during a power failure; an electric fireplace does not.
Sources
Specifications from Dimplex published product data, architectural specifications, and the Ignite Aspire installation manual. Kingsman comparison figures from the Kingsman Fireplaces United States Price List effective March 1, 2026. Gas decommissioning and electrical work must be performed by appropriately licensed professionals; requirements vary by jurisdiction.
Weighing gas against electric more broadly? See where electric wins and where gas still does, and our room-by-room sizing guide.
