Buying guide
A multi-fuel stove gives you a choice. Logs give a lively flame and are easy to come by; smokeless fuel burns hotter and longer and needs less attention overnight. The difference is all in the grate, and it changes how you size, run and install the stove.
What is a multi-fuel stove?
Wood and coal-type fuels like to burn in different ways. Wood burns best on a flat bed of its own ash, with most of its air coming from above the fire. Smokeless fuel needs air from underneath, so it sits on a grate with an ash pan below, and the ash has to be shaken through (riddled) to keep the air flowing.
A multi-fuel stove is built to do both. It has a riddling grate, an ash pan and two air controls: primary air feeds the fuel from below, which smokeless fuel needs, and secondary air comes in above the fire and across the glass, which is what wood needs. A wood-only stove usually has no grate to riddle and relies on secondary air.
The Carron ECO 5kW is a wood-burning stove that you can convert later with the Carron BHC810 multi-fuel kit, so it suits anyone who wants wood now and the option of smokeless fuel later.
What can you burn in a multi-fuel stove?
| Fuel | How it burns | How to run it |
|---|---|---|
| Seasoned or kiln dried logs | Lively flames, quicker to heat up, burns down faster | Thin bed of ash, mostly secondary air, little or no riddling |
| Approved smokeless fuel (such as anthracite or manufactured smokeless ovoids) | Steady, intense heat with small flames, long burn times | Primary air from below, riddle regularly, empty the ash pan before it fills |
| Wet wood, treated or painted timber, household rubbish, house coal | Smoky, tarry and in some cases illegal to buy | Never |
Buy a smokeless fuel your stove's manual lists; in England, manufactured smokeless fuels must carry the Ready to Burn mark. Logs should be under 20% moisture, and in England any wood sold in quantities under 2 cubic metres must be certified Ready to Burn. Traditional house coal can no longer be sold for burning in homes in England.
Switching fuels. Follow the manual when you swap from wood to smokeless fuel or back. You may need to clear the ash bed, change how much you riddle and set the air controls differently.
Sizing a multi-fuel stove
Start with the usual rule of thumb: about 1kW for every 14 cubic metres of room. A 6m x 5m room with a 2.4m ceiling is 72 cubic metres, which points to about 5kW.
The twist with multi-fuel stoves is that the output can change with the fuel. Approved Document J says the air supply for a stove that burns a range of fuels should be designed for the fuel that gives the highest output. That matters at the 5kW line, below which most homes built before about 2008 need no dedicated air vent.
| Stove | Output | Efficiency (wood / smokeless) | Max log | H x W x D |
|---|---|---|---|---|
| FDC4 Eco | 4kW | 81.8% / 79.8% | About 300mm | 510 x 370 x 210mm |
| FDC5 Eco | 5kW | 81.7% / 79.5% | About 300mm | 510 x 370 x 260mm |
| FDC5W Eco | 5kW | 80.8% / 81.6% | About 375mm | 570 x 440 x 260mm |
| FDC8 Eco | 8kW | 81.1% / 82.9% | About 375mm | 570 x 440 x 310mm |
| Woolly Mammoth 5 MK2 | 4.6kW wood, 4.9kW anthracite | 78.7% / 77.4% | 250mm | 540 x 420 x 290mm |
| Woolly Mammoth 5 Widescreen MK2 | 4.6kW wood, 6.2kW anthracite | 75.6% / 79.9% | 330mm | 515 x 475 x 300mm |
| Woolly Mammoth 8 MK2 | 8.2kW wood, 8.6kW anthracite | 78.7% / 79% | 400mm | 575 x 570 x 295mm |
So the Woolly Mammoth 5 stays under 5kW on either fuel, while the 5 Widescreen gives 6.2kW on anthracite and would normally need an air vent if you plan to burn it. Your installer will check the figure on the data plate. Our guide to air vents for stoves explains the sums.
Multi-fuel stoves in smoke control areas
Multi-fuel stoves are a good answer for anyone in a smoke control area, which covers many towns and cities across the UK (your council can tell you if you live in one). Authorised smokeless fuels can legally be burned there in any appliance designed for them. Wood can only be burned in a stove that is exempt for smoke control areas, using the fuel and settings its exemption covers.
All four FDC Eco stoves and the three Woolly Mammoth stoves here are listed as exempt, and so is the Carron ECO 5kW. That means you can burn dry logs or authorised smokeless fuel in town as long as you follow the manual. If your stove is not exempt, you can still use it in a smoke control area on authorised smokeless fuel only. See all smoke control approved stoves.
How to choose between them
The stoves in this collection come from three makers, and each has a clear strength.
FDC Eco. Compact, efficient steel stoves with ceramic firebox liners and a top or rear 125mm outlet. The FDC4 and FDC5 share a 370mm wide front that fits many original fireplace openings, and the FDC4 is only 210mm deep. The FDC5W and FDC8 share a 440mm front with a bigger window and take logs of about 375mm. All four carry a ClearSkies Level 5 rating.
Woolly Mammoth. Steel bodies with cast iron doors, with bolt-on leg extensions that lift the stove to leave a log space underneath, and direct air adaptors for taking combustion air from outside. The maker has since moved to MK3 versions of these stoves.
Carron. The ECO 5kW is cast iron in seven finishes, from matt black to sage green and cream enamel, with the multi-fuel kit sold separately. It suits a traditional room and anyone who wants colour.
- Small or shallow fireplace: the FDC4 Eco at 210mm deep.
- Typical living room: the FDC5 Eco, or the FDC5W Eco for a bigger view of the fire.
- Large or open plan room: the FDC8 Eco at 8kW.
- A colour to match the room: the Carron ECO 5kW with its multi-fuel kit.
Running a multi-fuel stove
The habits are slightly different depending on what is in the firebox.
- On wood, leave a thin bed of ash, keep the primary air mostly closed once the fire is going, and run on secondary air. Riddling a wood fire just loses the ash bed it likes.
- On smokeless fuel, open the primary air, riddle gently once or twice a day to drop the ash through the grate, and empty the ash pan before it fills up to the grate. Ash piled under the grate stops air getting in and can overheat and warp the grate bars.
- Glass. Smokeless fuel is cleaner on the glass than damp wood. If the glass blackens, the fire is running too cool or the fuel is wet.
- Sweeping. Fire and rescue services recommend sweeping quarterly while you burn wood regularly and at least once a year if you burn only smokeless fuel.
Looking after the grate. The grate and the firebox liners are the parts that work hardest. Check the grate bars for warping and the liners for cracks at the end of each season, and replace them before they fail; a sound grate keeps smokeless fuel burning evenly and protects the stove body.
Our guides to lighting a stove and stove maintenance cover the rest, and common stove problems helps if the fire will not behave.
Multi-fuel or wood only?
If you will only ever burn logs, a wood-only stove is slightly simpler: no grate to riddle and a firebox designed around an ash bed. A multi-fuel stove earns its place if you want a long, steady overnight burn from smokeless fuel, if logs are hard to get or store where you live, or if you want the option of authorised smokeless fuel in a smoke control area. Many owners burn logs in the evening and switch to smokeless fuel in the depths of winter. If you are undecided, the Carron ECO 5kW lets you start on wood and add the multi-fuel kit later.
Installation
A multi-fuel stove is installed in the same way as a log burner: in England and Wales by a HETAS registered installer who self-certifies the work, or with your council's building control; in Scotland and Northern Ireland, your council's building standards or building control rules apply. A carbon monoxide alarm to BS EN 50291-1 is required in the room; the SleepSafe COA10 has a sealed 10 year battery.
- Flue. Every stove here has a 125mm outlet. Approved Document J allows a 125mm flue for closed stoves up to 20kW that burn smokeless fuel or are exempt for burning wood. Your installer will line the chimney or fit a twin wall flue to suit, connected with 125mm stove pipe.
- Hearth. FDC specifies a 12mm hearth extending 225mm in front and 150mm each side for its Eco stoves, and Woolly Mammoth says its stoves suit a 12mm hearth. See our glass and granite hearths.
- Clearances. Distances to combustible materials vary by model; FDC's are smaller with its optional rear heat shields fitted. The manual for each stove is the reference.
Common questions
What is the difference between a multi-fuel stove and a wood burner?
A multi-fuel stove has a riddling grate, an ash pan and primary air from below, so it can burn approved smokeless fuel as well as wood. A wood-only stove burns logs on a bed of ash and is not designed for smokeless fuel.
Can I burn wood in a multi-fuel stove?
Yes. Burn dry logs under 20% moisture on a thin bed of ash with mostly secondary air, and avoid riddling the ash away.
Can I burn coal in a multi-fuel stove?
Approved smokeless fuels such as anthracite, yes, if the manual lists them. Traditional house coal can no longer be sold for burning in homes in England.
Can I burn wood and smokeless fuel together?
Check the manual for your stove. Each fuel needs different air settings and grate handling, so most people burn one at a time and follow the maker's advice when switching.
Are multi-fuel stoves allowed in smoke control areas?
Yes. Authorised smokeless fuel can legally be burned in a smoke control area in any stove designed for it. To burn wood there, the stove must be exempt; the FDC Eco, Woolly Mammoth and Carron ECO 5kW stoves here are.
Do I need an air vent for a multi-fuel stove?
In England, not normally for a stove rated at 5kW or less in a home built before about 2008. For multi-fuel stoves the figure used is the output on the fuel that gives the most heat.
What flue size does a multi-fuel stove need?
At least the size of the outlet, 125mm on every stove here. Approved Document J allows 125mm for stoves up to 20kW burning smokeless fuel or exempt for burning wood.
Can I convert a wood burner to multi-fuel?
Only if the maker offers a kit. The Carron ECO 5kW converts with Carron's BHC810 multi-fuel kit.
How often should I empty the ash pan?
When burning smokeless fuel, before the ash reaches the underside of the grate, usually daily in regular use. When burning wood, leave a thin ash bed and only remove the excess.
How often should the chimney be swept?
Fire and rescue services recommend quarterly while burning wood regularly and at least once a year for smokeless fuel only.
Which multi-fuel stove is the most efficient?
In our range, the FDC8 Eco is rated at 82.9% on smokeless fuel and the FDC4 Eco at 81.8% on wood.
Find your multi-fuel stove
Compare outputs, sizes and log lengths on each listing, or ask us about a specification.