EcoSmart Fire
EcoSmart Fire Flex 158SS Fireplace Insert
EcoSmart Fire Flex 158SS Fireplace Insert
In stock
Largest and widest size in the Flex range
Free UK Delivery
- Up to 45,870 BTU/h (triple XL1200) Ethanol Burners
🚚 Estimated Delivery Date:
Delivery date to be confirmed via email once order is placed
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Buying with confidence
- Manufacturer warranty: 2 years on the bioethanol burner and stainless steel parts, 1 year on everything else.
- 45 day returns. Unused and in its original packaging.
- Damaged on arrival? Check it before you sign, and tell us as soon as you can, ideally within 48 hours, so we can sort a replacement quickly. This does not affect your statutory rights.
- Free UK mainland delivery.
- Not sure it is the right one? Call, email or chat with us before you order.
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Overview:
- The Flex 158SS is the largest and widest size in the Flex range, a 4230mm opening running three burners across its full-width All Flame configuration. Unlike 68SS, 86SS, 104SS and 122SS, which each offer four configurations, the 158SS offers only two, All Flame or log boxes on both sides, with no single-side log box option.
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Design & Build:
- Zinc-sealed mild steel surround and toughened glass, built around triple Grade 304 stainless XL1200 burners in All Flame form (45,870 BTU/h combined from a 30-litre tank), stepping down to triple XL900 burners when log boxes sit on both sides. The burner is available in Stainless Steel as standard, or a Black ceramic-coated finish for a flat, monochrome look, at a fixed premium.
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What it does well:
- All Flame runs 9 to 14 hours per fill and is rated for a 345m³ room, the largest of any size here. Even the log-boxes-both-sides configuration still runs three burners at 45,000 BTU/h, more output than every size below 122SS manages at full width.
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Trade-off worth knowing:
- At 4230mm and up to 222kg, this is the single largest architectural commitment in the range, a genuinely bespoke wall installation, not a retrofit. If that scale isn’t needed, the 140SS or 122SS deliver comparable presence at meaningfully less weight and cost.
Flex 158SS questions, answered
Does the Flex 158SS need a chimney or flue?
No. It runs on bioethanol, which burns clean with no smoke, embers or soot, so there is nothing to vent. It frames into a wall or opening with zero clearance to combustibles - no masonry chimney, gas line or flue required.
Can the Flex 158SS be used both indoors and outdoors?
Yes, it is rated for both. Indoors it needs a room of at least 345m³.
How is the Flex 158SS installed?
It frames directly into a stud wall (wood or metal) or an existing hearth opening, with zero clearance to combustibles required around the frame. There is no gas line, flue or masonry work: once the opening is framed to size, the unit drops in and connects to nothing else. At 222kg (All Flame) it is a two to four-person lift into place depending on the model; check the exact figure on this page before planning your install.
What does the Flex 158SS actually cost to run for an evening?
A full 30 litre fill burns for 9-14 hours. We sell e-NRG bioethanol at £65 for a 20 litre carton, so a full fill is about £98 and a three-hour evening works out at roughly £21 to £33. There is no standing cost, since it only uses fuel while it is alight.
Which Flex size should I choose?
The 158SS is the largest and widest size in the Flex launch, with the longest single-fill runtime (9-14 hours) and the largest room rating (345m³) of any size here. If that scale isn't needed, the 140SS or 122SS deliver comparable presence at meaningfully less weight and cost.
Which fuel does the Flex 158SS burn, and do you sell it?
It runs on e-NRG bioethanol, which we stock in 20 litre cartons. Bioethanol produces no smoke, embers or ash, so there is nothing to clean out after use.
Are there any accessories that fit the Flex 158SS?
Yes. Its triple XL1200 burner takes the XL Baffles and Black Glass Charcoal, sold separately.
Is the Flex 158SS certified for indoor use?
Yes. This model is certified to EN 16647, the UK and EU safety standard for indoor bioethanol fireplaces.
Who the Flex 158SS is for
It is a good fit if:
- You are commissioning a genuinely bespoke wall installation: the single largest architectural commitment in the range.
- Even the reduced log-boxes-both-sides configuration still runs more output than every size below 122SS manages at full width.
Consider something else if:
- That scale is not needed: the Flex 140SS or 122SS deliver comparable presence at meaningfully less weight and cost.
| Model | Burner | Pick it for | Opening width | Price | Weight |
|---|---|---|---|---|---|
| Flex 18SS | AB3 | Narrowest, fits a tight wall recess or stairwell | 578mm | £1,495 to £1,795 | 25.7kg |
| Flex 32SS | XL500 | First step up to the XL burner family, nearly double the heat | 1010mm | £2,995 to £3,445 | 45.7kg |
| Flex 42SS | XL700 | Shares its burner with the wider 60SS, no log box required | 1265mm | £3,695 to £4,145 | 60kg |
| Flex 50SS | XL900 | First size offering an integrated log-storage configuration | 1470mm | £4,095 to £4,595 | 71.4kg (All Flame) |
| Flex 60SS | XL700 | Log box standard, no All Flame option at this size | 1725mm | £4,545 to £5,095 | 83.9kg |
| Flex 68SS | XL1200 | Largest single-burner size, four configurations at one price | 1930mm | £4,795 to £5,295 | 97.1kg (All Flame) |
| Flex 78SS | XL700 | Log boxes on both sides as standard, no All Flame at this size | 2186mm | £4,795 to £5,245 | 108kg |
| Flex 86SS | twin XL900 | First size to need twin burners for full-width All Flame | 2390mm | £6,995 to £7,995 | 122kg (All Flame) |
| Flex 104SS | twin XL1200 | Even a single log box still runs twin burners | 2850mm | £7,995 to £8,995 | 146kg (All Flame) |
| Flex 122SS | triple XL900 | First size to run three burners across All Flame | 3310mm | £9,995 to £11,495 | 172kg (All Flame) |
| Flex 140SS | triple XL900 | Every configuration carries at least one log box | 3770mm | £11,395 to £12,895 | 195kg (single log box) |
| Flex 158SS (this one) | triple XL1200 | Largest and widest in the launch, two configurations only | 4230mm | £12,395 to £13,895 | 222kg (All Flame) |
Prices are current at the time of writing; follow any link for that model's live price.
Delivery Information
Delivery Information
Key Points of Interest
Key Points of Interest
Specifications
Specifications
| Category | Details |
|---|---|
| Material | Mild Steel (Zinc Sealed, High-Temp Powder Coat) Surround, Toughened Glass; Grade 304 Stainless Steel Burner |
| Weight | 222kg (All Flame), 219kg (log boxes both sides) |
| Dimensions (W x D x H) | 4230mm x 365mm x 807mm |
| Surround colour | Black |
| Burner finish | Stainless Steel (standard) or Black ceramic-coated (+£1,500) |
| Fuel | Bioethanol only (Indoor or Outdoor) |
| Thermal output | 45,870 BTU/h (48.4 MJ/h) |
| Burn time | 9-14 hours per fill |
| Fuel capacity | 30 litres |
| Minimum room size (indoor use) | 345m³ |
| Burner compliance | EN 16647 compliant burner (manufacturer-approved) |
| Configuration options | The Flex 158SS offers only two configurations, not four — All Flame (triple XL1200, 45,870 BTU/h, 30L, rated to 345m³) or Log Boxes – Both Sides (triple XL900, 45,000 BTU/h, 27L, 330m³). There is no single-side log-box option at this size. Both configurations are the same price. |
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