Renewable heating dilemma

[dalivar]

I've got so many things in my head at the moment, its keeping me awake at night Sorry this is a bit long.
The oil boiler needs replacing, so we're looking at renewables. We're also about to get a wood burner anyway and so I'm fairly convinced our best bet is to get a burner stove and link it to an accumulator tank to make enough hot water to heat the radiators in the winter. I'd also like to invest in solar PV or solar thermal to give us hot water during the summer (luckily we're south facing) and not bother with any regular boiler. Has anyone here done this?

We're not greedy when it comes to heat, we've coped with a single open fire for the last month and don't have a great need for hot water (electric shower, very, very rare baths). The house is mostly stone so we feel underfloor heat won't be sufficient and are happy to keep the radiators.
The solar PV or solar thermal would both provide some income to help cover the installation costs, as could the stove if we get an approved one. We're also lucky in that there is a good MCS approved installer very local to us.
I know its worth looking into but its such a big decision, it would be the first big investment into our house - every thing else so far has only cost a few hundred quid.
Can anyone help with similar experiences?

 

[MdB]

Think hard about solar PV. When I looked, the payback was 5 to 10 years and that was before the subsidy value was dropped so it will be longer now. If you come to sell your house before this period is up you won't get your money back through increased value of the house. I spoke to four or five estate agents and they all said the same thing, it may make your house easier to sell but it won't increase the value. Conclusion was, that unless you can guarantee that you will be in the house for longer than 10 years, you won't get your investment back.

If you are doing it from a "green" perspective rather than a financial perspective then solar PV isn't great either in the UK. Our weather just isn't ideal for it with current technology. Solar thermal is a lot better.

 

[Flyfisher]

I can claim a lot of experience with the dilemma but much, much less with the best solution.

A big part of the problem, I think, is that people's circumstances are so different - and I don't really mean financial, although that too is a consideration. If you're at home all day then it's easier to keep topping up a wood stove, but if you work all day do you really want the bother of lighting a fire and waiting a couple of hours before the place warms up and you have enough water for a shower? Also, unless you have a ready supply of free wood it's very expensive to buy these days. But if you do have a wood stove then it seems a shame not to use it for hot water as well, but you may want to consider it as supplemental rather than the main source of heat.

If you're competent with a spreadsheet, I'd suggest playing around with various scenarios. You,ll need to determine your energy requirements whatever system you eventually choose so it's good to start with some basic figures. Thereafter, it's not too difficult to estimate operating costs using various fuel options. Start with electricity, including the cheap overnight tariffs, to give yourself a baseline reference point. Then gas (if you have it), oil, coal, wood, and solar Thermal and PV.

You may find the results surprising. I did and my conclusion is that a mains gas system will be the cheapest to run and this has caused me to change my focus from a wood boiler-stove plus heat store as the primary heat source plus gas as a backup, to gas as the main system with the wood boiler stove as supplementary.

My hope is that we'll only use gas heating for the very coldest months and use wood for the other 'cooler' months. During the summer, gas would only be used for DHW. This is the plan and everything will be installed before the summer so this time next year I'll know what sort of mistakes I've made!

I've also considered solar PV but, regrettably, I have to agree with MdB. I may revisit it in the near future as its an instinctively good idea, but the current economics soon takes the shine off it.

 

[dalivar]

There goes my simple answer then :roll:
I have read that solar thermal would work best with my proposed idea, I just prefered the idea of being able to use solar electricity for other things as well. Flyfisher makes a good point though, I had read that the accumulator tank is so well insulated that a single burn can store water for several days, however if I'm running the radiators off it then I will be losing the accumulated heat. I suppose so long as we use the stove every evening then there should be enough hot water stored overnight to at least start the next evening of radiator heat before the burner is properly up to temperature.
We do have access to some free wood but as we are in a fairly rural area there is cheapish wood to be had. Of course when everyone has changed to timber as a fuel I'm sure the cost of that will rocket too. We are looking into pellet boilers too since we don't have gas (the gas main ends about 30m away from our house), but I was put off by having to buy prepared pellets which are also likely to increase in price. Its so hard to know what to do, and as for staying in the same house for 10 years, who knows what might happen. I wouldn't like to commit to that.

 

[dalivar]

Out of interest what sort of installed prices have you both seen for solar PV? Our installer will fit 4kw for just over 6k.

 

[Flyfisher]

My thoughts on the heat store were that, first, the boiler stove could be given a good burn, which I understand is the most efficient way to burn wood and, second, that the stored heat could be used to drive the radiators via a timer to take the chill off the house on cold mornings before getting up.

As for mains gas being only 30m away, I'd say that makes it a very feasible option. We had no gas to the house but the main supply wasn't a lot further than yours. I spoke to the gas people and they said the standard connection charge was £250 but because we were further it would be £300 plus the cost of digging the pipe trench. They advised me to arrange the trenching if possible because they said they just subcontract it and it's very expensive. I found a 'man-with-a-digger' who did the job for £200. This was about 3 years ago.

 

[Flyfisher]

Last time Imloked at solar PV the cost was going to be around £10k but I can't remember the capacity. I did't pursue it too much because I had other priorities for the money and I knew the FIT rate was about to be reduced. Also, being listed, it would have taken a while to sort that out so all-in-all I became distracted by other more urgent things.

I'd really like to revisit it sometime though because it 'feels' like a good thing, though I do worry about the payback period.

 

[worms]

I guess most of us are somewhere in the same dilemma. What I struggle with is the crystal ball needed to work out payback times. The capital cost is fixed at installation, but the utility cost is rising all the time as are the running costs from the various fuels. Will electricity continue to rise at 8-10% per year? When the global recession ends will oil and gas prices rocket? Will wood fuels simply track oil prices? And that's without even factoring in currency risks!

 

[Flyfisher]

And in addition to those valid points, what about the technology variables? Will PV systems generally become cheaper and more efficient, thereby significantly reducing the payback times?

I'm beginning to wonder if I shouldn't just use mains gas while I can still afford it and leave the trees until the time comes that fossil fuels are unaffordable - though by then we'll probably have rioting on the streets and marauding gangs of people looting every tree and bush still standing. :wink:

I heard something on R4 during the week about the "new deal" for energy (or whatever they call it) whereby you have an energy survey done and identify what energy-saving improvements can be carried out. You then take out a loan to cover the work and the repayments are made from the energy savings. So, in theory it doesn't cost you anything. However, the loan remains tied to the property so any future purchaser still has to effectively pay higher energy bills until the loan is repaid. At least I think that's how it all works, though anyone interested should find out the real facts and not rely on my half-baked description.

 

[skier-hughes]

I have A 40kW wood burner with back boiler, a 900l accumulator tank, radiators, 50 x solar thermal tubes and 4kw solarpv.
What would you like to know.

The solar thermal gives us plenty of hot water all summer long, well about April to September, only on the very odd occasion do we have to light a fire to heat the water.
In it's first year our solar pv produced 3068kWh, returning us about £1300 from the FiTs and cost us £12 to install, but we did go for high quality panels and due to the tubes being on the roof we had to either go for a lot less pv panels or in the end we decided to have 3 inverters fitted, as one chimney causes shading at times.
The 40kW fire eats wood, we have a plentiful supply of free wood, fallen trees, trees I chop and also timber from a shed manufacturer and also a fence manufacturer. We have a lot of space tied up in wood store, and I spend a lot of time cutting down trees, chopping wood, storing it and then bringing it in each day. I reckon I get through 2 x tonne builders bags of wood each week, more in the very cold weather.
The 900l tank was the biggest we could fit in the space it was going in, and is sufficient for us to have a couple of hours central heating first think of a morning on the really cold days, or a days worth of background heat on just cold days.
Inside our 900l tank is a 200l domestic hot water tank, so we have around 700l as heating water.
I would in hindsight and room gone for a slightly bigger tank, but it would have take much longer to heat it up properly, needing bigger fire and more tubes!!!
We have 19 rads of quite large sizes. We are working at home nearly every day.
We used to have an oil fired rayburn supplying all hot water and heating, but it just couldn't cope.
The house is a decent size, 1300's, very well insulated in loft, poor on walls and has double glazing.

There you go, feel free to ask more questions or pm me if you want a chat.

Personally as the gas is only 30m away I'd get connected, the one thing I'm not looking forward to is chopping and carting wood around when I'm 90!!!!!! Our nearest gas main was over 500m away.

 

[MdB]

Having gas 30m "can" be expensive to connect up. In a previous property we had gas a similar ish sort of distance away and the quote was £3k to connect up as it involved digging up the estate road. No option to dig our own trench unfortunately.

 

[worms]

Our nearest gas is also about 500 m away, but in our case it is the high pressure gas grid line and the nearest domestic line is about ten miles away!

 

[Flyfisher]

Having gas 30m "can" be expensive to connect up. In a previous property we had gas a similar ish sort of distance away and the quote was £3k to connect up as it involved digging up the estate road. No option to dig our own trench unfortunately.

In our case, I only had to pay for digging a trench to the boundary of our property and the gas people did all the necessary work from that point to their gas supply. That involved digging a few holes in a roadway and using a mole to get the pipe between them.

A good driver with a mini-digger should be easily capable of digging a 30m trench and refilling it in a single day and I'd be surprised to have to pay more than £300 for that. I'm in no way disputing your £3k figure though, because the gas people told me it would cost 'thousands' if they had to arrange it.

The £300 I had to pay the gas people included their work up to our boundary, laying the new gas pipe in my prepared trench, installing the gas meter and connecting and testing everything. It was clearly a very subsidised price because they had three people on the job for two days plus a subcontractor to repair the holes in the roadway.

Having said all that, I wouldn't be at all surprised if things vary around the country, but it's certainly worth making enquiries.

 

[Flyfisher]

Our nearest gas is also about 500 m away, but in our case it is the high pressure gas grid line and the nearest domestic line is about ten miles away!

Sounds like a similarly frustrating situation to our lack of mains sewerage even though there are two pressurised sewer pipes that run under our garden!

 

[Zebra]

I reckon I get through 2 x tonne builders bags of wood each week

Lordy!

 

[worms]

Sounds like a similarly frustrating situation to our lack of mains sewerage even though there are two pressurised sewer pipes that run under our garden!

Pressurised sewer pipe? :shock: I didn't know they did such a thing! That would make a bit of a mess if the pipe blew! Although so would our high pressure gas main!

 

[LadyArowana]

Sounds like a similarly frustrating situation to our lack of mains sewerage even though there are two pressurised sewer pipes that run under our garden!

Pressurised sewer pipe? :shock: I didn't know they did such a thing! That would make a bit of a mess if the pipe blew! Although so would our high pressure gas main!

I think it's a case of "been there, done that" as far as FF is concerned :lol:

http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=12742

 

[worms]

I think it's a case of "been there, done that" as far as FF is concerned :lol:

http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=12742

Well remembered, LadyA! I remember that thread but must have missed the "pressurised" bit!

 

[Flyfisher]

Yes, not the nicest sort of leak. Fortunately it was well away from the house so not a big problem. The grass has certainly recovered very well though!

The pipes in question run from a small pumping station where all the foul drainage from the village is collected. It is then periodically pumped to a small treatment plant about three miles away. As you can imagine, it takes a fair bit of oomph to pump a three mile pipe full of, er, you know what, so a break in the pipe about half a mile from the pump house means that the contents will take the easier route up through the soil to freedom.

 

[88v8]

If you mean it's 100 ft away, then forget all other ideas and get digging.
If it's 30 miles, that might be another matter.

Says me, who lived 35 years with gfch and now has storage rads + 2 x woodburners.

Ivor