for anyone who may be interested,

Ive spent quite a bit of time now looking at biomass boilers, GSHP's and solar thermal, with an eye to installing one or possibly two of these technologies into the 1960's bungalow i am going to refurbish and extend. I have came to the conclusion that financially it will be much cheaper to use the oil boiler in conjunction with a simple multi-fuel stove fitted with a boiler. These two boilers will be connected together via a thermal store or possibly a low loss header tank.

I will mainly be burning wood and if I get everything sized correctly, hope only to have to fire the oil burner in the summer time to produce hot water for the day.

The biomass boilers will require around 5 tons of pellets a year for the proposed size / insulation level of house @ £260 per tonne approximately plus the installation costs of anything between 15k to 25k. the government payment would be approximately 2000-2500 pounds per year for 7 years.

I have joined a local oil club and the last oil order was 49p per litre plus VAT @5%. In my case I believe it will be significantly cheaper for me to run oil and wood than the latest renewable technologies.

I collect all of my own wood from people who want trees removed and local skip hire plants who have piles of very dry old timber removed from skips and have to pay to have it carted away. I get it all for the cost of my petrol and time to get it. It doesnt take up as much time as people may think either.

Its always in the news about oil running low and sky rocketing. I work in the oil and gas industry, albeit not involved with estimating resources, but the truth is that the world is huge and only a fraction of it has been explored for oil. A figure I heard banded about was 3% has been explored. With advances in deepsea drilling and exploration, I think the scaremongering about oil reserves is that, purely scaremongering. I cannot see it running low in my or future children's lifetimes.

In the mean time I'll save my cash for a 5.0 supercharged instead of spending it on the latest "green technology" MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Sounds like a plan fella

Are you going to run one great big tank or 2-3 smaller ones in the attic space to spread the load across the beams and capture every last kW of heat output?

One design I came up with a fair while back had small stove with back boiler outside the house with manual control valves on the in and out pipes, that way it could be run every now and again in summer and not heat the house up.

Side benefit was that it would likely have been in the leanto that would be a store for drying wood and a mini greenhouse.

Used stoves and backboilers are pretty cheap. FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

Thats a really good idea having an outdoor stove with quater turn valves to use in the summer... Im not to sure yet about what sort of tank to use. I will need at least an cylinder for hot water and a thermal store. I currently have about £1500 worth of unvented indirect cylinder and all associated valves and pressure vessel that I bought for my current house, but never needed to use as the 40kw combi was plenty. so i would like to use that if possible. the general consensus is that you cannot connect a solid fuel stove to a unvented cylinder, but it seems you can get around it by not having it connected directly, by using a thermal store. I really need to get a heating engineer's opinion as the more you go into it, them more comlpex it gets. Broseley make a stove with saftey features built in so that it can be connected directly to a pressurised system. MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Iirc some self installers got away with a decent sized bath room towel rail fed directly from the backboiler then upto the store tank.

You could in theory use two tanks. One for heating one for hot water. That way storing up for both systems and along good use of the runs from a secondary external stove unit.

Downside would be you would need 3 header tanks to keep the two separate systems and the hot circuit always filled with water and for the heating and hot circuit antifreeze corrosion inhibitor stuff. FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

My understanding of the RHI tariffs is that while the commercial side get 20 years of payments the amount paid is much less each year which is why its over 20 years.

While with domestic RHI the payments are much higher over a shorter 7 year period to help popularise the tariff as many domestic users did not want to wait 20 years to get there money back.

Maybe I am over simplifying things but it might be worth adding up the total RHI payments over the respective periods to see if there is a substantial difference or not. If the RHI payments are approx. the same then it might be better to get your money back in 7 years rather than 20.