Think a few on here use biomass to heat their homes.
I’m
Looking into a wood pellet boiler and thermal store for heating our new build.
What’s the pros and cons of this system?
Any help appreciated

Good friend put in biomass for his big build as he gets paid for using it it.

I this the biggest issue is the quality of pellets – a bad load can make life difficult.
He also lost 6 weeks of heat last winter waiting for a replacement auger from Sweden.
His setup is massive in terms of the space required.

Indirect experience here, but my parents have one and work have them in some properties.

Without RHI payments the running costs weren’t a great saving over oil when I was involved with our work systems.

They also take a little more involvement. Ash pans to clear, pellet hoppers to fill or if you have a silo store for blown pellets the auger or vacuum will need some attention from time to time. Flues can be funny with strong wind.

Most of the time they are just fine and do all you need. My view on them may appear negative, but that is because my main involvement with them is when something has gone wrong, mostly through operator negligence.

Alternatively a friend’s new build farmhouse uses ASHP, underfloor heating downstairs and massive thermal store in walk-in airing cupboard.

I’ve liked the idea of them, but they have some very questionable greenwash invested in them, and seem to work best at a scale bigger than your average home.

Our local school and leisure centre had a system linked to both sites, so that involved a separate building for it, seemed to be a fair few maintenance issues with them and then there was the questionable sourcing of the wood for pelletisation and it’s shipping etc.

My original plan was ashp but with rising electric costs and bigger how water demands it seems it will be very heavy on electric. There is a local company 5 miles from me who install maintain and sell the pellets.
Just makes more sense to use biomass. Boiler and thermal store would go in garage giving off some nice heat.

Having worked with both, if you are on a new build house then a heat pump is probably the way forward unless you have free logs and can use a biomass log boiler. Even then I would think twice…
Unless your house is massive you should be able to use a relatively small unit, install should be cheaper, hot water not an issue with a decent heat pump and design.
You could consider ground source if you wanted to add cooling too although does add cost and potential complication.
Message me if you want more info

Logs in batch burners makes more sense, but didn’t mention it due to space and storage. A sawyer friend has one on their farm burning the waste from the mill to heat 2 farmhouses but not even your average double garage would be big enough for the burner, 5000l tank and timber billet stacks. He fills the burner every 2 or 3 days over winter.
Incidentally they have solar panels for an electric aga, but in OP situation could equally support the ASHP?

He fills the burner every 2 or 3 days over winter.

I think if you haven’t lived with one the sheer physical volume of stuff you feed into them is quite surprising. I used to have oil and would look at the 1000ltr tank  – a whole cubic meter and think ‘blimey – we’re going to burn all that this winter’ when we were switched over to biomass, serving 6 properties and we’d watch a tractor load in 5-6 cubic meters of chips every 2-3 days. Compared to oil wood just isn’t very energy-dense so theres a volume difference anyway, but wood boilers aren’t stop/start the way oil or gas would be.

Basically we’d just hear chainsaws all day pretty much everyday and over 6 years or so we watched the landscape around us gradually disappear and go up in a great big RHI-funded puff of smoke.

I think for certain applications (apart from obviously being a machine for transferring public money into private hands)  they’re maybe fine – they suit being on all the time and therefore you (or someone) being in all the time. They’d be a great system for a hotel or a school. Our boiler was running winter and summer, day and night whether I or my neighbours were in or not (on even if they were offshore for months at a time) . Now that I’ve got a conventional gas boiler even in late November  it hasn’t so far been on for more than an hour or two in total each day and its an interesting reminder in just how much unused heat our old system was generating.

They can take a bit of tending to as well – keeping on top of stocks or material (can the supplier still get wood to you in the snow) getting them running reliably, getting someone reliable to actually turn up to service and repair it, getting reliable supply of spares. They have interesting foibles like the fuel freezing together and not going into the hopper in the temperature really drops. It took 4-5 years before ours wasnt a bit of an ongoing saga. I think this last year has been the first when there weren’t any major let downs, we’d gone for up to a week without heat in the past.

They’d be a great system for a hotel or a school.

Seen some relatively new systems in schools replaced with gas boilers, so not that great, used to do quite a few systems a few years back, can’t think of when we last did one.

greenwash

Whole lot of that going on, even known some systems being installed that owner was planning to take out as soon as development had been signed off by planners.

Get the building fabric right and use an ashp. Biomass generally have pretty dodgy green credentials and are not appropriate for a well insulated low energy new build.

They’d be a great system for a hotel or a school.

Seen some relatively new systems in schools replaced with gas boilers, so not that great,

I was more meaning the ‘always on’ nature of them, rather than the biomass, as being more suitable to a building thats always occupied rather than a private home. Although if a school (or any property) has a gas supply there was never really a good case for having biomass instead anyway, other than for show.

Build your house to passivhaus standard, get the entire south facing roof covered in solar, a big battery and look into micro wind too. Your trickery should pretty much be free and if it’s an air recovery system, your house will be warm and you’ll have plenty of hotwater if you use the solar/wind and the AHSP to heat it.

If I had the money, that’s exactly the system I would use and perhaps a woodburner in the main living area.

Get the building fabric right and use an ashp. Biomass generally have pretty dodgy green credentials and are not appropriate for a well insulated low energy new build.

☝️

This.
Simple is best.

Get the building fabric right and use an ashp. Biomass generally have pretty dodgy green credentials and are not appropriate for a well insulated low energy new build.

👆 This….

We have a bio mass that heats my whole village (30+ houses, several workshops, church, village hall and school). But it’s an estate village and the wood comes from the estate within 2or3 miles of the boiler. The wood is stored a few 100m away and is chipped on site. It’s as green as a biomass can be, but takes a huge woodland to manage it and and to be green and self sufficient as possible.

It’s also comparatively expensive to run even using their own wood. Around 14p per kWh from what I’ve heard – forestry is expensive even at cost pricing.

So basically house is approx 157m2 4 bed with ufh on ground and 1st floor. Wood burner in living room. Well built with good spec insulation. We didn’t put solar on roof due to cost but plan to in the future. With rising elec costs will heat pump be expensive to run?
Biomass looks good option but more cost to install.
Need to make up my mind soon and get it installed.
Thanks for all your help and advice so far

Not everyone’s idea of good spec insulation is the same. I don’t even have heating upstairs and haven’t run any heating yet this winter and still at 21 degrees. As before, good building fabric and Ashp. What you need is heat loss calculations from someone who has a clue. Impossible to spec your heating remotely

If you know the u values for all of the building elements and even better, a result from a door blower test, you will be able to get a reasonably accurate heat loss calc done. That should tell you exactly how much it will cost to heat your home…… Assuming the builders weren’t cowboys and actually fitted your insulation properly and didn’t cover all your walls with dot and dab plasterboard.

That’s the thing, I am the builder and painstakingly insulated then double taped every last bit. Built with care and attention. Hopefully pay off in the future

I’d love a big system taking logs and dumping into a thermal store. The idea of loading up every 3 days and letting it do it’s stuff seems super. The cost is a lot though, I guess there’s just not enough sales volume. So in reality, an ashp but also a really big stove being fed with logs is probably what I’d end up with. That said, the ‘really big stove’ is not a common thing in the UK and hence not cheap either.

That’s the thing, I am the builder and painstakingly insulated then double taped every last bit. Built with care and attention. Hopefully pay off in the future

It will.
Have you done calcs on heating needed or not needed?