Hi all!

Just found this forum and am starting to read through back topics, wow! what alot to learn.


We (2 of us no kids) have a single storey bungalow and we are looking at our options for better/more efficient/greener options for heating and hot water.

We have an old oil boiler and a tank that urgently needs replacing, as we are now on mains gas, a new gas boiler is a given I think.

We definitely want to add Solar hot water, and a we want a stove (open fire currently).

I thought I understood all this until we thought of back boilers, and then somebody mentioned Thermal Stores.

So now what?

How expensive would it be to combine all of the above compared to just Solar HW and gas?
Do installation companies/plumbers understand it (we are in Fife)
How much benefit would we get?

I realise these are "how long is a piece of string" questions.

Does the added hardware and installation cost give extra benefits?
Is the complexity an added hassle?

Thanks
Ian

Unless you've got a plentiful and cheap supply of wood a back boiler will still cost a fair bit to run, may be more than a good mains gas boiler, and it will certainly be hard work.

I dont beleive that burning wood is as green as some people suggest- I dont know anyone who burns wood that replants anything like the volume they use so eventually we'll have burnt all the trees available!!!!! I've planted quite a few trees on our land but nothing like the volume of wood I'm burning.

Install solar HW and insulate to the extreme if you want to be green.

Tricky one for you to decide.

My sister got a little morso squirrel, no back boiler, and a few logs renders the room it is in lovely and toasty, and she always says she regrets not having the back boiler option.

However, the whole point of boiler stoves is that they heat the water; not much heat goes into the room, so you need loads more wood to get the water warm AND the room warm.

I personally really enjoy the whole cycle of coppicing now, splitting and seasoning, and bringing in the wood for the heating, but I can see it won't be everybody's favourite task.

...so if your primary water heating is coming from gas, and you don't have free wood, maybe a straight highly efficient and fairly small wood stove (no boiler) is the thing.

ianmack:

Martin makes a very valid point. There is a world of difference in wood consumption between say, a squirrel (great little stove) with a DHW + 1 rad (8-10 000 Btu/hr) boiler, and a full-on woodburning CH boiler. And not just because you have a bigger maw to fill - but because to harness the additional useful energy produced by a wet stove, you have to run it harder.

The squirrel with boiler could burn just about the SAME amount of wood as a dry version, albeit with less heat going to the room (the corresponding loss of room heat going to water) - so in this respect, you might say that the 'waste' heat goes to water for very little extra wood, but at the expense of room temperature - which may be toasty anyway so it doesn't matter. Good gig.

While thermal stores - my own and customer's - are a passion of mine, be in no doubt that you will use several tonnes more wood PA by opting for a big stove and boiler. This is true whether it is a room stove like my Clearview 650 and wrap boiler, or Vigas gassification unit, though the latter is undoubtedly more efficient at water production. The added wood consumption does bring benefits, but you have to decide if they are benefits you need or whether you could get away with a dry stove/maybe plus DHW boiler for DHW and a gravity rad.

If you use a suitable thermal store, benefits are semi-automated use, a reduced fossil fuel footprint and the ability to harness future, possible more automatic technology.

For now, you could of course add other eco-appliances into the mix to reduce the wood consumption. I shall be running a 9 KW ASHP and 6-8 solar panels when I get round to it. Constant tinkering in the name of science is such good fun :))

Meantime, however much wood you burn, get it in bulk and store 18 months - 2 years min. Split into 2 piles. Use one til pile is empty, then switch to other pile while replenishing first. Make each pile around a year's worth or more, and you'll be a happy woodburner. For best woods to use and an amusing bit of doggerel re firewood, go to www.aie.org.uk

Even Ash, one of the few grade four hardwoods and one of the best woods to burn green (not recommended) fares better if you can season it. And yes, Martin, I agree, it is therapeutic getting wood in - they say it warms you twice, once when you cut/split it it, once when you burn it :) Tho coppicing can be hard work!

Happy hunting

Crusoe