Log Biomass Boiler System

matelodave

I've had a good look round the Ofgem site and can't find your 45kwh limit anywhere (that's not say it doesn't exist - but it's not mentioned). You might have to ask Ofgem yourself for clarification. Likewise I'm not sure if you can put in a bigger boiler than you need just in case you want to extend the building or heating system at a later date.
I'm sure that the RHI has some limits otherwise there would be those who would try and claim it for a stately home - perhaps they can, but then it might not come under the rules for the domestic portion.


Whilst looking I found a calculator which I tried out using the non EPC estimator and it's spot on for my situation (bungalow with air source heat pump). I've got a recent EPC and am receiving the RHI based on my heating & hot water demand

captainhindsight_2

Bit of a difficult one, to qualify for domestic RHI you have to use MCS approved boilers and installers.

However MCS only certifies up to 45kW, (commercial installs and RHI don't require MCS) so in short you need to fit two boilers.

Say you need 60kW, you will have to install two 30kW boilers which are commissioned and installed as a single install/heating system and then claim the domestic RHI.

matelodave

So to clarify, it's not the amount of heat you need that's the limiting factor but the size of boiler.
So multiple boilers (presumably from the approved list) can be installed to supply the required heat demand?

captainhindsight_2

matelodave wrote: »

So to clarify, it's not the amount of heat you need that's the limiting factor but the size of boiler.
So multiple boilers (presumably from the approved list) can be installed to supply the required heat demand?

Yes, for domestic RHI multiple boilers from the approved list can be installed to supply the required heat demand.

So a house with a heat demand more than around 60,000 kW is likely to need multiple boilers if they want to claim domestic RHI.

It will make it more expensive, the list price for the ETA SH 60 is £9,034 and the list price for the ETA SH 30 is £7,734 (+VAT) (both log burners) so potentially another £6k.

It may be worth the OP seeing if they can claim the commercial RHI instead, lower payment per kWh but over 20 years not 7.

PaulBowen

Biomass boilers can be worth their weight in gold, because with them you can get RHI which means any unused energy can be fed into the grid, and you get paid for that energy too - so it's really handy stuff. Plus the fuel costs are a lot less than your average gas bill too so if you can get one, you should go for it.

I guess it's hard to know where to turn though when you're after one of these things - after all there are plenty of firms but how do you know which one to use ? For me I just got some quotes in and did some googling too that's how I ended up with stl heating. I mean there may be some firms near you, but do get some prices in first.

Smiley_Dan

PaulBowen wrote: »

Biomass boilers can be worth their weight in gold, because with them you can get RHI which means any unused energy can be fed into the grid, and you get paid for that energy too - so it's really handy stuff. Plus the fuel costs are a lot less than your average gas bill too so if you can get one, you should go for it.

I think you might have your subsidies mixed up. This only applies to the FiTs for electrical production (PV and wind mainly). I guess there might be a biomass CHP boiler which could provide FiTs but that's not RHI which is just an incentive to use renewable sources of energy (as the name suggests).

Robwiz

Generally it's better to choose a larger capacity boiler for logs or wood chip because it's most efficient to burn hard and get the heat energy into the thermal store. There's a case to be made for installing a 40 kW boiler when the heat demand is 24 kW because it will need loading and running less often.

If you have a 45 kW boiler you might need to burn several batches on the coldest days, but much depends on the size of your thermal store. A good installer will be able to advise and lay out options.

captainhindsight_2

I would agree with that for logs, but I would disagree for wood chip boilers.

Wood chip boilers have just as much control and functuality as wood pellet boilers so there is no need to burn in bulk to get the highest efficiencies or convenience

captainhindsight_2

Also for log biomass and the rhi , the Walltherm boiler is going through the motions with mcs atm is a great product now but would be even better if it qualified for Rhi
http://www.walltherm.ca/

villabadger

captainhindsight wrote: »

So a house with a heat demand more than around 60,000 kW is likely to need multiple boilers if they want to claim domestic RHI.

It will make it more expensive, the list price for the ETA SH 60 is £9,034 and the list price for the ETA SH 30 is £7,734 (+VAT) (both log burners) so potentially another £6k.

Hi

I've not yet had a green deal assessment but to satisfy my curiosity I have had an EPC done. The figures are:
Space demand (kWh per year) = 61,358
Water demand (kWh per year) = 3,169
Impact of loft insulation = (4,715)
Impact of solid wall insulation = (19,978)

At first glance it appears that I would need a 65kW boiler but if I can prove that the house is properly insulated then does this mean that only a 40 kW boiler would be needed? is this how it works?

I have loft insulation in the house but an attached building (still considered part of the house) still needs doing, which is not a problem. The walls are stone constructed and approx 2 ft thick with lathe and plaster 'skin' on the inside of each outside wall. This obviously creates an air gap. Is this considered as insulated, even though no modern material is installed? Or would I still need to fit insulated plasterboard to satisfy the requirements?

The house was built around 1850 (not listed) and the front elevation still has very large sash windows which are single glazed. To me, most heat loss would be through these. Would the demand be significantly affected by not replacing these, as there is not a calculation specific to this?

Any ideas?

Thanks