A Good Life 





Proud Co-Founder of Transition Town High Wycombe


Proud Member of the Low Carbon Chilterns Cooperative



Proud owner & retrofitter of Superhome 59

Superhome 59


This website proud host of the High Wycombe Local Food Guide

Local Food


Gas Boiler Replacement 2008

Well - you have seen the old boiler and here it is again (left). Although we moved in during May this Gas Boiler was not replaced until August. It was high on the list of things to do after the extra insulation. However it took three months because we spent a lot of time trying to get a Wood Pellet Boiler in to replace the Gas Boiler. However, by August we realised that this was not going to happen very quickly so made a quick decision to replace the Boiler during the warm weather rather than procrastinate until the Autumn or Winter months. The problem with the Wood Pellet Boiler (more details below) was that we had to get a licensed appliance for our Smoke Control Zone plus Planning Permission for the Flue in our Conservation Area. This, coupled with the lack of response from one of the Suppliers, killed a lot of time with no progress. So we bit the bullet and got a very quick turnaround from a local plumber we had used before. Within about a week he was in a ripping out the antique leaving a gaping hole on the wall (shown right). In total it took two men four days to do the job even if they worked at a somewhat leisurely pace. It only cost us more Tea and Biscuits!



Soon the new boiler is in place. It is much smaller than the old one. The flue is smaller too which means that you have to get part of your wall bricked up so as to not leave a large hole. The Condensing Boilers also need a water drain into a waste pipe. It can't just be left hanging out the wall like the over-flow pipe to a toilet. It has to be protected from freezing up. You will also find that, even if you don't want them, your plumber will want to fit Thermostatic Radiator Valves (TRV) on all but one or two of your Radiators. This will be to bring you up to Building Regs - or so they say. No worries these are much better for controlling local room temperature than normal valves. Our plumber wanted to replace the Domestic Hot Water Cylinder but we drew a line there. We knew it had only been there for about five to seven years so it wasn't that old. The second reason is that it would probably be replaced anyway when the Solar Thermal Panels go in. At our request we also had the main room Thermostat and the central Controller/Timer replaced. These are described in a little more detail below.


The Boiler we have had fitted is just 18kw. We might have had a large one but we explicitly requested that it be under-sized because we knew we would be fitting:


  • Solar Thermal Hot Water Panels on the roof that would supply 50 to 60% of the Hot Water requirements anyway

  • A Wood Pellet Boiler rendering the Gas Boiler as a backup only. Since the Domestic Hot Water Cylinger could supply Hot Water (only true before it was replaced by a Geldhill tank in 2010 when the solar thermal panels went up) then even in backup mode we would only need it for Heating in Winter

  • Cavity Wall Insulation and 300mm of Loft Insulation before Winter


We had the new Timer/Controller placed inside the Kitchen (adjacent to the Garage where the boiler is) so no more tip-toeing out to the Garage to change the settings. This caused some sudden and unexpected debate between my wife and I as she would have preferred the Controller out of sight and out of mind. However, I persuaded her that it would be in her best interests as she will be the last person wishing for a trip to the Garage at night to fiddle with the controls. We can now see very quickly if anything is on or off allowing a quick over-ride if required. The Controller controls the Hot Water and Heating on separate programs so one can be off whilst the other is on. We have three program slots per day with a separate program at the weekends. This avoids us having to have the boiler on for too long, instead it can 'pulse' during the day and maintain the temperature. The weekend program also helps us get the optimum heat when we need it which tends to be a couple of hours later than on a working day. Boilers are at their most efficient when they are hot. To this end the programs applied have tried to have the Hot Water and Heating on at different times so that the Boiler is working on one or other but not both. (This also helps as the Boiler is slightly undersized.)


The new Room Thermostat was originally requested largely for cosmetic reasons. The old one looked very dated and was of questionable functionality and probably at the end of its life. However, when invited to replace it our plumber (long knowing our love of energy-saving gimmicks) fitted a Thermostat with a built in time-lag. This responds to ambient temperature so it will delay the heating process if it believes it will reach the target temperature quickly. It sounds good but in practice it is hard to see if this would be anything other than a cause of frustration for users wanting instant response. It might be useful if you want the house to be warm when you come home from work but where the house is mostly occupied during the day this is of questionable value. After-all you do have a sophisticated Timer to control when the heat comes on. We'll see how this works in practice. However, one very useful feature of the new Thermostat is that it has a simple internal mechanism that limits the upper and lower reach of the thumbwheel gauge. This can be set to prevent users for 'wacking it' up to 30 degreesC and leaving it there in the belief that the house will get warmer quicker. This was set to limit the Thermostat to 24 degreesC - more than enough.


All-in-all the new package of Condensing Boiler, Controller, Thermostat and TRV's should wipe 40% of the fuel bill over-night. This in addition to the new Cavity Wall Insulation and 300mm of loft Insulation should see us reducing the cost of Heating and Hot Water by half. These costs will drop again when the Solar Thermal Panels come on Tap. With the addition of the Wood Pellet Boiler, to take most of the heating load, and large-scale Photovoltaics for most of the power should render us very near carbon-neutral.








Low Carbon Man

  • A bit of disruption and this always costs more than the pundits say.

  • This is a bit of an easy win and every home should have the boiler upgraded. Feels good to stop wasting gas.


The Battle of the Wood Pellet Boilers 2008-2009

We will have a Wood Pellet Boiler eventually. However it has been an adventure trying to make any progress on the matter. We did a lot of research on the matter and read a few books. We knew we were in a Conservation Area so we would need Planning Permission for an external Flue. So there was no way we could hide the install from the Council. As the area was also in a Smoke Control Zone we would (at least in theory) need a licensed appliance - and they are not many of those. In May 2008 we contacted two companies selected because:

  • One was 'local' ie, within about twenty miles

  • The other had published experience in getting non-licensed appliances installed in Smoke Control Zones - Green Systems UK

If you do the research you find that it is technically at the discretion of your Local Environmental Health Officer (EHO) to allow non-licensed Wood Burning Appliances to be installed within their Smoke Control Zones (SCZ). There are many cases where the EHO would inspect the appliance after installation to confirm that there is no visual smoke. That is all that is necessary. Others may require proof that the Appliance reaches European Standards. Still others refuse to do anything at all and only allow listed appliances. The interpretation of the Clean Air Act is so diverse that the EHO can interpret it any way they want. So, if your supplier/installer knows how to sweet-talk the EHO and the EHO is receptive then the world should be your oyster as there will be dozens of appliances available in the UK for installation in SCZ's.


 As things turned out, after initial interest from the local supplier they dropped off the radar. After several weeks of them ignoring and failing to return my E:Mails & Phone calls I gave up pursuing them. The second supplier was better and gave me good quotes for a Baxi and a KWB. However as soon as I asked about the flue they also vanished off the radar and I couldn't get hold of them. They had all disappeared off to do a job. Obviously it was a very small company with no capacity. This left me a little nervous that I had all my eggs in one basket. The KWB is licensed for a SCZ but is extremely expensive. The Baxi is not licensed and had only just decided to attempt to get a license. This could take 6 or more months and cost them £10k (GBP). Baxi are a big Company so they can afford it. What was clear was that nothing was going to happen quickly.


So we sat back and decided to look around the market to see what else was out there. On the 20th August 2008 (or thereabouts) I contacted nearly twenty supplier/installers with an invitation to tender for the job. We quickly got a diverse set of replies. Many declined to help but several were very helpful. In summary we learnt this:


  • Bioenergy came back for a quote for the Mescoli CombiFire2 but it isn't licensed. They have sent me more brochures and a long E:Mail but there Boilers seem over-sized. They, like several others, are convinced they can persuade the local EHO but two previous attempts by other installers has failed. I won't pursue them. However they did supply lots of useful information. For example Building Regulations say that the Flue has to be 3m from a neighbour's house and 1m above the nearest opening window within a 3m radius from the open top stub.

  • Ashwell Engineering sent us a brochure-cum-quote in the post. They also phoned and seemed keen to help. Their installer in Warwickshire phoned me too (Bob Smith at Sterland Elgar). They gave me lots of information on the phone about flues, Thermal Stores, Hot Water Tanks and the ease in which they can connect everything in parallel to an existing Gas Boiler as backup. However their boilers are not licensed so they cannot help me.

  • Treco E:Mailed me and phoned me. They also believed that they could convince the EHO that their installation would be smoke free. They spoke to the local EHO but could not make any headway. Sadly they can't help further.

  • Graham Thornhill at Cosi was very friendly and had lots of advice even if he couldn't help me. He was not aware of the SCZ restrictions.

  • ECOlink came back to me with Brochures and Price for one PH23 Boiler but it seemed too big. There was no specific quote for the install and the basic boiler cost over £15k + VAT. Very pricey for a useless lump of metal. There was no other supporting data and no info on a SCZ License. I won't pursue them further.

  • Oxon Wood Heat came back with a very comprehensive quote for what we assumed would be their Solar Focus Pellet Top. However they seemed to estimate that we needed a Boiler in excess of 18kw apparently consuming 3.5 times more fuel than we currently burn (including cooking!). Their largest hopper size is 250l which they suggested would not be adequate so they quote for a separate hopper and auger system. The total cost came to a mind-boggling £20k+ which was easily £5k more than the next most expensive install. It all seemed too big and too expensive. The only good news was that they were hopeful of getting a SCZ License soon.

  • Broag Remeha had been very helpful and offered their HPK - RA Pellet Boiler (Broag-Gilles). They are licensed however their quote excluded everything from installation to VAT. I suggested that they put all the hidden extras in. I did my own rough guesstimate of all the missing costs and it looks as if they remain very price competitive. However, the reply from them on mid-September was quite depressing. They couldn't even tell me the correct VAT rate quoting 17.5% whereas I already know it would be 5%. They went on to reveal that they are not registered as an installer with the Low Carbon Buildings program suggesting you won't get a grant. They suggested a hire an external Consultant and Contractor to design and perform systems integration with my existing Heat System. The very idea is ludicrous. However I did find that there was an installer called Energy Innovations (UK) Ltd who were eligible for grants from the Low Carbon Building Program.

  • Windhager E:Mailed suggesting their BioWin Boiler which will become licensed. However they initially told me it would be impossible to fit a Gas Boiler in parallel. However I followed up with their Installer as I don't think they have considered using a Thermal Store. Their installer has called me and was very helpful. He recommended a twin coil tank rather than a thermal store (as did Ashwell Engineering) and had lots of ideas for connecting up the Gas Boiler as backup. He even was aware that WindHager had a new control system for release next year that would get around all the connection problems as it could control a second boiler. He will make enquiries and I invited him to tender for the install. I have also found that Glendevon Energy & Solar Thermal are certified with the Low Carbon Buildings program to install BioWIN.

  • Green Systems UK with the KWB as mentioned earlier. They are also certified to install with a grant from the Low Carbon Buildings program.

  • One that hasn't been tried is the Herz Firematic range available from Rural Energy who are accredited as installers for the Low Carbon Building Program. This is certified for a SCZ but maybe slightly over-sized as their web site only lists "small Commercial" installs, not domestic...?

  • Another is the Binder RRK 22-49 which is certified for a SCZ and available from Wood Energy Ltd who are accredited under the Low Carbon Buildings program. They maybe over-sized though...?


As things stand on September 2008 we are still awaiting some replies. Some of the difficulties we have had are in trying to get an appliance in our price range with an inclusive quote. Every quote has a problem, it either misses out most of the work, isn't for a licensed product or can't connect in parallel with our Gas Boiler. We have had problems getting a meaningful description of the Flue (although we have just enough information now to apply for Planning Permission). So we either wait for Baxi to get their Wood Pellet Boilers licensed or for one enterprising installer to convince the EHO that their Boiler is OK in SCZ. One thing is clear - this is turning into a long running project. The average householder in the UK today (in any built up area) is going to have to have a lot of money, a lot of patience and a lot of luck. The market is clearly in its infancy with plenty of barriers for early adopters. Obviously the Planning Regulations for Flues are a hurdle as is the Clean Air Act which is clearly our of date. Local EHO's don't have one firm opinion on the matter so it is down to luck if your Local Air Quality Officer will entertain non-licensed product in their SCZ. We also need a lot better choice in small Wood Pellet Boilers with bolt on Hoppers of decent capacity. The contrast with our Gas Boiler refit is clear. For the Biomass Market to catch up with Fossil Fuels then we need to:


  • Rewrite the Clean Air Act to exclude modern biomass appliances in the same way that gas boilers are excluded

  • Re-engineer Pellet Boilers so they can be flue-less

  • Reduce the size of the boilers and reduce their price. You can get a Gas Boiler wholesale for £600 (GBP) but the wood pellet boiler will cost at least ten times as much. There is not enough choice.


We'll keep you posted on the "Battle of the Boiler". Post-Carbon Living would like to thank all of the people and Companies named above for their sterling efforts. However, a big thumbs down to the local Air Quality Officer for being completely unable to do something that her colleagues in the London Boroughs (just 20 miles away) do all the time. You have a lot to learn. Out of interest I picked up this gem from the Government's own Planning Policy Statement 22 "Emissions from biomass fuel combustion include limited quantities of gaseous nitrogen and sulphurous oxides [but these emissions] are significantly less than those from comparable fossil fuel stations. Under certain conditions (particularly in cold weather) a steam plume may emanate from the chimney. This is non-polluting, the only consideration being the visual effect. As a matter of Policy the Government recognises that Wood Pellet Boilers are less polluting than Fossil Fuels. As a matter of Law the Wood Pellet Boiler is more tightly controlled. Why? The law is an ass.


***UPDATE: 29th April 2009*** In the intervening time we had tried to get a Flue installation quote for the Broag-Gilles based upon the Energy Innovations quote. However, our favoured plumber never got back to us whilst the other quoted nearly £9000. I spoke to Energy Innovations and they suggested that the figure could be closer to £5000. Either way I had only budgeted around £3000 based upon my other research. Either figures would make the Broag-Gilles uncompetitive with the original KWB quote from Green Systems UK.


By January we proceeded with Planning Permission for an external flue. It was rejected. Apparently the neighbour didn't like the idea based upon some long running angst over some Leylandi trees (that we inherited with the property - not our fault!). The Planning Department suggested that we reduce the width of the flue to that used on gas appliances which was utterly ludicrous. We went back the drawing board and suggest two new proposals - one at the back of the property and another through the interior. They rejected the external mount again but told us that they would waive any requirements for the internal fit.


Next we applied for the Low Carbon Buildings Program Grant - this was ridiculously easy and seemed automatic based upon our online application. We guess they had loads of money in the kitty. Next we invited Paul from Green Systems around who took some measurements for a SAP rating. From this he will know what the final boiler rating will be. It could be as low as 10kw. It sounds as if KWB have a new range of even smaller boilers.



Low Carbon Man

  • Getting a biomass boiler requires lots of money and space. It is also a real hassle trying to find someone to fit it for you, in the way you want, at a reasonable cost.

  • In terms of carbon-saved in relation to cost a biomass boiler is a big win.


Biomass Boiler Installation 2009

Paul Elliott-Smith, of Green Systems UK, started the installation in the first week of August. The KWB Boiler had arrived from the factory in Austria well wrapped in a sturdy wooden crate. It was very heavy and arrived with a sizable buffer tank (seen to the right if the boiler). After a couple of days the boiler was de-crated and moved into its final position. From there a network of pipes were establish that joined to the existing pipework around the Gas Boiler. The positioning of the boiler was dictated by the exit point of the flue and the need for the Pellet Hopper to be swung away to gain access to the Boiler for maintenance. It took seven days work to establish the pipework.


As you can see the Boiler and Buffer Tank are sizeable. It needs its own boiler room or garage. It will take up half the space of the garage leaving the remainder free for fuel storage (approx three tonnes). The average family home will need four to six tonnes of Pellets per year. Obviously the Boiler will need power and connection to your heating system. So a garage joined to the house is essential - preferably one where the existing boiler is there already. In our case we chose the house specifically with these points in mind. The garage here is a double garage so we retain the use of the garage whilst half of it becomes boiler room and bunker house.


The set of four photo's (above) show the initial chaos as the boiler is unwrapped and removed from its packing case. This is all still in the first week of August 2009. Within the day the buffer tank and boiler are tidied way into their final resting places in the corner of the Garage. Pipe runs are established between Boiler and Buffer Tanks then between Buffer Tank and the existing Gas Boiler (mounted on the wall next to the window). The two white semi-spheres, on the floor under the window, are expansion tanks.


The four pictures (above) were all taken in the same first week of August 2009. The spider's-web of pipework continues to grow and encroach upon the gas boiler as it curls itself around the window. The heating system is drained and the old gas boiler is disconnected. The old system is now joined to the new system. The KWB Easyfire will now be the master and the old Gas boiler will be slaved to it. The Gas Boiler now feeds the Buffer Tank.


The four pictures (above) show progress up to the 13th August when the flue was installed. Due to Planning Restrictions this has been fitted internally within the fabric of the building. It passes vertically up through the garage ceiling and then along the corner of the bedroom above. (See pictures below.) From there it passed up through the roof void and through the roof. It passes through a flashing kit to terminate above the roof line.


The four pictures (above) show the progress from the 15th to the 19th August concerning the external Flue. The two sets of photo's may look the same but there is a crucial difference. The first set of photo's has the Flue too high above the roofline. The Planning Permission was only waived on the grounds that the top of the flue would be no more than 1m above the ridgeline. Thankfully the problem was corrected soon after with a shorter section of upper flue.


The four pictures (above) mostly deal with the intrusion of the boiler flue through the bedroom above. This part could have been tricky as no one really wanted a boiler flue through their bedroom. Hence we quickly worked with a builder to have the flue boxed off with plasterboard. The area was quickly redecorated and the furniture put back.


As you can see from the photo's a good job was done with little inconvenience. This area is intended to be turned into an en suite shower room at some point so the flue may well "disappear" all together behind stud walling.


The four pictures (above) deal with the Pellet Storage area. This had to be next to the boiler with a 30cm separation for fire safety reasons. The space marked out on the floor (the white box) marked off this clearance zone and is approximately 2m x 2m x 2m allowing for 8 cubic meters of storage. (The other two lines on the floor represent the clearance required to close the garage door and get a car in the garage.) Eight meters cubed equates to approximately 4 tonnes which is about 80% of annual requirements. To be conservative we only shipped 3 tonnes to see how it would all fit.


As you can see there were some problems. The Pallets are 1m x 1.2m so three of them should have fitted in the space without unloading. However, when they arrived they were found to be stacked outside of the pallet footprint, ie, there were large over-hangs. This made it impossible to store more than two inside the box. Hence the third had to stay outside the garage. Surprisingly it only took 20 minutes to unload that one pallet. Hence the second pallet was also restacked giving us plenty of space to play with.


It is clear that the storage, put-away and man-handling of wood pellets (in 15kg bags, in this scale) is going to be a significant obstacle for most householders more used to the convenience of Gas. But if you are strong and like a bit of exercise.........!


The four photo's (above) show the final installation with all the pipe insulation installed. You can also see how easily a small car (Toyota Aygo) fits in the space left over. A bigger car would also have fitted easily even with three tonnes of pellets - this is not a problem at all if you have a double garage.


These photo's were taken on the 19th, 20th & 29th August. By this time we should have had the Boiler commissioned. However, we hit a snag. Although the boiler worked fine the buffer tank would not fill properly due to a mistake in the valve configuration on the pipework behind the boiler. A new valve had to be ordered and this was not fitted until Saturday the 29th August. Commissioning was not scheduled until the 4th September due to the holidays and non-availability of Commissioning Engineers in this period. Hence the entire installation had taken (on & off) five weeks.


Compare this to a Gas Boiler fit of only three to five days. Be prepared for inconvenience. Certainly if your install is a domestic residence then try and get it done in summer so no heating is required. We used the immersion heater in the Domestic Hot Water Cylinder for the period when the Gas Boiler was off-line.

The next set of photo's come from late September 2009. The Garage-cum-Boiler room got quite warm at times and it was quickly clear that there were significant gaps in the insulation on both pipes and buffer tank. The buffer tank has spare entry/exit ports that are capped but they penetrate the thick insulation providing an excellent and unwanted thermal bridge. At times they were very hot. The pipework had exposed metal at every valve, wall support and major joint where the standard insulation didn't fit. To resolve this problem we took spare insulation and a sharp knife to cut what we needed to shape. It was a loose fit but secured with cable-ties. On the Buffer Tank we added circular cones cut from Radiator Foil (thin expanded polystyrene sheet backed by foil) over the exposed metal. This was glued on with wallpaper paste. Then a sheet of foil-backed bubble wrap was added over top secured by silver gaffer tape. The results can be seen in the photo's above with the work-in-progress on the left and the finished result on the right. The picture (left) shows the before and after for the pipe insulation. See how the pieces are carefully crafted with a knife and secured by cable-ties. Valves are not covered nor should they be.



Low Carbon Man

  • Installation proved to take much longer than thought and required replacement of an old radiator that sprung a leak.

  • Reasonabley happy with the result. The RHI should have made this a real economic winner.

The Renewable Heat Incentive - April 2014

On April 10th the UK domestic Renewable Heat Incentive came into effect. Unfortunately the Superhome 59 KWB will not qualify due to a quirk of fate. Our Commissioning Certificate is dated September 2009 but the installer did not get his MCS certification until one month later. Hence, despite qualifying for all the requirements for a Low Carbon Building Program Grant under the [then] Blue Skies scheme (fore-runner to MCS) we cannot get the RHI. This was a source of deep disappointment given that the equipment is MCS certified. However, after some anguished discussion with Gemserve they declared that there was no way to get the equipment re-certified by an MCS installer. They are unwilling to be flexible. Given that we do no have a time machine nor do we possess any clairvoyancy we have pointed out the utter impossibility of this situation. This Biomass Boiler was installed with the sole purpose of qualifying for the RHI as then known about. As we cannot have known in 2009 that the Blue Skies scheme would not be honoured by the 2014 RHI then this remains grossly unjust.

Update - 2010





In November 2010 we had Green Systems UK back for the first annual maintenance of the KWB. Everything went well, no problems. It is relatively straightforward and can mostly done by the householder in future years.


In September 2009 we installed a Water Softener (pictured right) in the garage in order to protect the new heating system. This will keep the radiators, thermal store, and solar DHWC all clear of limescale and enhance the life of all components.


In November 2010 we also had the original room thermostat replaced with the full digital controller (pictured left). The original room stat proved unreliable and we found radiators on at times we couldn't understand. The upgrade allows us to control the boiler from within the home rather than having to exit into the garage. It has a digital readout showing the room temperature. Oddly it seems calibrated to be 2 or 3 degrees below reality.


The new room stat sits alongside the Photovoltaic remote readout and a temperature display (pictured left) giving us internal and external temperatures. It looks a little like mission control here in the lounge. At a glance we can see how most of the new systems are performing. The only item missing is the Solar Thermal Controller that sits in the Airing Cupboard upstairs.









Low Carbon Man

  • Additional cost and nonsense!

  • A few extras were necessary to protect the investment and get the best from it.



References: References