Estimating biomass boiler size

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We've had 4 quotes for biomass boilers which have suggested boilers from 95 to 195kw. One of the companies has visited a few times but I'm not sure if they've spent long enough here to perform a full heat loss calculation.

We need to install radiators throughout most of the building & I've calculated the BTU required for each room (though I understand I may need to multiply this by the number of air changes and difference between lowest outside & desired temperature. Is this right or will the BTU multiplier I've used for each type of room (to calculate radiator size) already have taken this into account? The BTU calculations seem to suggest a need for 60 kw of power + another 10 for 3 to 4 hot water cylinders plus 38 for a second building. Which suggests that a boiler around 100kw in size should suffice.

I've carried out a quick heat loss calculation looking at heat loss via walls, floors, windows & rooves (and the appropriate multipliers for each part of the building, type of glazing etc.) This also seems to come in around 90 kw.

Am I missing something obvious? Heat loss from.pipework is included in one quote & costed at £10 of fuel p.a. so I haven't missed much there.

Unrelated to that (but related to quotes over budget), about half of the quote from the company who spent most time here is for separate thermostats and "variable temperature heating packs" which, with labour costs, add on between £3k & £8k a zone (and we have 6 zones!). My plumber/electrician who's not connected with the biomass bit is getting other things up & running suggests there are much cheaper & simpler solutions, we couldn't remotely control each zone from an Ipad but could still have separate timers/thermostats for each zone.

Any help appreciated.

Em
 
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Largest two have a 3 kw rating, smallest is 2 kw, not sure if we need a 4th.
 
Contact windhager, okofen, eta, hoval, varobaroen.

They're manufactuers of decent quality biomass boilers.

They have an installation network of recommended installation companys.

Get in touch with those companies and you'll stand a good chance of getting a decent job done.

biomass is the latest cowboy industry.
 
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We've had 4 quotes for biomass boilers which have suggested boilers from 95 to 195kw. One of the companies has visited a few times but I'm not sure if they've spent long enough here to perform a full heat loss calculation.

We need to install radiators throughout most of the building & I've calculated the BTU required for each room (though I understand I may need to multiply this by the number of air changes and difference between lowest outside & desired temperature. Is this right or will the BTU multiplier I've used for each type of room (to calculate radiator size) already have taken this into account? The BTU calculations seem to suggest a need for 60 kw of power + another 10 for 3 to 4 hot water cylinders plus 38 for a second building. Which suggests that a boiler around 100kw in size should suffice.

I've carried out a quick heat loss calculation looking at heat loss via walls, floors, windows & rooves (and the appropriate multipliers for each part of the building, type of glazing etc.) This also seems to come in around 90 kw.

Am I missing something obvious? Heat loss from.pipework is included in one quote & costed at £10 of fuel p.a. so I haven't missed much there.

Unrelated to that (but related to quotes over budget), about half of the quote from the company who spent most time here is for separate thermostats and "variable temperature heating packs" which, with labour costs, add on between £3k & £8k a zone (and we have 6 zones!). My plumber/electrician who's not connected with the biomass bit is getting other things up & running suggests there are much cheaper & simpler solutions, we couldn't remotely control each zone from an Ipad but could still have separate timers/thermostats for each zone.

Any help appreciated.

Em

Be careful a lot of these Greenwash companies are run by ex double glazing sales men & con men. As soon as the Grants change they go belly up, as with the PV solar companies. As above, go to the manufacturers & get one or two of their approved installers to quote - more chance of getting a tradesman then.
 
These are Eta recommended installers, and we've visited other places where they've installed boilers, they just differ hugely in their specs.
 

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