Electric fireplace trim kits

A trim kit is a flat frame that covers the margin between your insert and your opening — and it only works inside a band. Too small a gap and you do not need one; too large and nothing on the market covers it. The reliable fix is to buy an insert whose manufacturer sells a matched surround, like the PuraFlame Klaus with its trim kit at 44.1 by 31.5 inches. If your opening is bigger than that, stop trying to fill it and use a log set instead.

It is a metal frame, usually black, that sits against the face of the masonry and overlaps the edges of the insert. It hides the rough edge of the opening, the fixings and any daylight between the firebox and the brick. It is cosmetic — it does nothing for heat, nothing for safety and nothing for the install beyond tidying the line where two things meet.

The reason it matters so much in this category is that inserts are sold by firebox width while fireplaces are built at whatever width the mason felt like. Almost nobody's opening is exactly 33 inches. So the normal outcome of buying an insert is a gap, and the normal fix is a frame.

Work this out before you buy anything. Measure the opening, subtract the insert width, halve it — that is the margin on each side the trim has to cover.

Quick picks: inserts with a surround, and what to do instead

Ranked. The running cost column is computed from each unit's rated wattage, not quoted from a manufacturer. Tap a row for the full write-up.

#	Product	Best for	Cost per hour	Price
1	PuraFlame Klaus 33" Insert with Trim KitThe Klaus insert with its trim kit in the box — 44.1 by 31.5 inches of coverage, which is the widest honest fix on this page.	The gap solved in one purchase	27.5¢1,500 W · 5,118 BTU	$501.99 · View on Amazon
2	PuraFlame Klaus 33" Electric Fireplace InsertThe same insert without the surround, for a lot less — the right buy when the masonry around it already looks good.	A tidy opening that needs no trim at all	27.5¢1,500 W · 5,118 BTU	$429.99 · View on Amazon
3	Dimplex Revillusion RLG25 25" Plug-In Log SetA log set makes the gap a feature instead of a problem — the honest answer when your opening is far wider than any insert.	When the gap is too big for any trim	27.5¢1,500 W · 5,118 BTU	$487.99 · View on Amazon
—	Touchstone Fireplug Pro 33 InsertA 33-inch insert with no surround option we could find — which makes it the wrong starting point for anyone shopping trim.Skip this one	Nothing, if the gap is your problem	27.5¢1,500 W · 5,118 BTU	$1,099.00 · View on Amazon

#ad Buy links are affiliate links — we earn a commission on Amazon purchases at no extra cost to you, and it never changes the ranking. How this site is funded. Running cost is computed at 18.34¢/kWh; see what these actually cost to run.

There is a market in third-party trim kits, typically sold for a specific competitor's model — you will see listings phrased as "trim for a 36 by 27 inch insert" or naming another product's ASIN outright. They cost a fraction of what a matched surround adds to an insert, and they are a legitimate option, with two caveats worth understanding.

• Fit is on you. A matched trim is engineered to overlap a specific firebox by a specific amount. A universal kit is a rectangle of the stated size; whether it sits flat against your masonry and cleanly over your insert is your problem to verify.
• Finish rarely matches exactly. Two blacks from two manufacturers are not the same black, and the difference is visible at the seam in daylight.
• Heat clearance still applies. A frame fitted tight over a heat outlet is a bad idea. Check what the insert's manual says has to stay clear.
• Buy the insert with the trim if you can. One purchase, one finish, one set of instructions, and nobody to blame but the manufacturer if it does not line up.

Three situations come up often enough to name, and in all three the frame is not the answer.

1. The opening is far too wide. Past roughly 44 inches around a 33-inch box, a trim kit stops framing and starts floating. Use a log set and let the brick do the framing — that is the argument on our log sets roundup.
2. The masonry is the problem, not the gap. If the brick is stained, painted badly or crumbling, a frame around the edge draws the eye to it. You want a full insert with its own lining, which is the case we make on log sets vs inserts.
3. The brick is genuinely handsome. Then buy the bare insert and leave the margin. A period fireplace with sound masonry looks better with a visible reveal than with a metal rectangle over it.

The trim changes nothing here — it is a piece of steel. Every insert on this page runs the same 1,500 W ceiling that a 120 V circuit imposes on the whole category.

The Klaus is one of the cheaper units on this site with a genuine two-stage heater, which over a season is worth more than the surround. The running cost calculator will price it against your own tariff.