Green Building Forum - Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

greenfinger — Sun, 06 Aug 2023 18:33:46 +0100

Hi

Sorry to return so soon with another wood stove question... This time it's about multi-fuel (MF) vs wood only (WO) stoves. From the reading I've done, there seems to be mixed opinions on whether a WO stove performs better than a MF stove, when burning wood only.

****Open Grate****. One of our shortlist stoves is the ACR Earlswood III and Astwood II. Both are MF and have grates with permanently open slots. See below for pics. The stoves tick a lot of boxes for us, but the grate puts us off. The manufacturer has said that it won't affect performance, so long as there's a good bed of ashes. But logic and the opinions of some on the net would perhaps suggest otherwise.

****"Hybrid"****. I used the term "Hybrid" in the title to refer to stoves like the Clearviews and Woodwarm Fireviews (others too I'm sure), which have riddling grates which can be put into a closed position and provide a flat bed. But there's still gaps between the bars so it's not a truly solid bed. And whilst the primary air can be closed (at least I know it can on the Woodwarm), I'm not sure if that totally prevents air getting through. A Woodwarm Fireview Eco is a contender.

****Wood Only.**** Another contender is the Dik Geurts Ivar 5. True wood only burner with vermiculite bricks on the bottom.

Any thoughts on the three types and how relevant or important the grate/base situation is for wood only, would be most appreciated. And just to add, I've read that a bonus of the MF and Hybrids is that the Primary Air coming in beneath the grate can be very helpful getting the fire going. Yet on the other hand, a WO without the grate and ashpan means a larger firebox.

Over to you guys!

Many thanks

Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

greenfinger — Sun, 06 Aug 2023 18:34:15 +0100

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Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

greenfinger — Sun, 06 Aug 2023 18:34:30 +0100

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Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

WillInAberdeen — Tue, 08 Aug 2023 09:26:40 +0100

The basic stove we inherited with our house is lit a few times a year (mostly during power cuts!). It's a MF stove but we only burn well-seasoned branches from our garden. Even so, the primary air seems essential for lighting the fire, and to keep it going at anything faster than a 'slumber'. Maybe a purpose designed wood stove would come with more substantial secondary air inlets?

The riddling grate and ash box are very convenient for cleaning it out.

It is important that all the air supplies can be completely closed, otherwise there will be a constant draft whenever it's not lit. Ours usually has a chimney balloon in it because of this, is a nuisance because have to disassemble half the internal bits (messy) to get access to the flue. Even if you are thinking about an external air intake (are you?), you don't want a continuous draft of external air blowing through the stove.

Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

Beau — Tue, 08 Aug 2023 14:34:32 +0100

In my limited experience, the hybrid ones have performed better than WO. Used a few Woodwarms over the years and one that was most disappointing was WO. Now it was the smallest of the three but the lighting was slow and it never ran as cleanly. Possibly smaller stoves don't get so hot could be why it was not cleaner but no doubt having the option of under air speeds lighting.

Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

Cliff Pope — Tue, 08 Aug 2023 15:56:06 +0100

It is important that all the air supplies can be completely closed, otherwise there will be a constant draft whenever it's not lit. Ours usually has a chimney balloon in it because of this, is a nuisance because have to disassemble half the internal bits (messy) to get access to the flue. Even if you are thinking about an external air intake (are you?), you don't want a continuous draft of external air blowing through the stove.

Doesn't the flue have a damper that you can close?

Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

WillInAberdeen — Tue, 08 Aug 2023 23:03:27 +0100

Mine doesn't (maybe it should?)

I somehow had the idea that flue dampers are not supposed to 100% seal off the flue, for safety reasons. But maybe I imagined that, because I can't find it written anywhere!

Multi-fuel vs Wood Only (and "Hybrids") when just burning wood...

GreenPaddy — Wed, 09 Aug 2023 07:57:07 +0100

May not apply for OP case, but in SAP for a new-build, a multifuel gets hammered on environmental rating, as it assumes coal being burned. Where as wood only stoves of course assume wood. It used to be about a factor of 20 worse for MF (haven't checked in the last couple of years).