I am lucky enough to have a pitched roof about 30-35 degrees from the horizontal facing approximately 185 degrees, so I’m thinking about some solar options.
Obviously one can purchase (expensive) consumer-orientated setups with inverters, storage, etc so that it basically integrates into your existing domestic supply and you just carry on as before but now using some of your own electricity.
What options are there for someone who’s happy to be more hands-on and happy to consider changes in the way they use power and/or certain appliances, hot water, etc? Someone who would prefer to purchase individual components and install them for a specific purpose (e.g. a DC immersion heater or some other water heating solution, a separate DC wiring system or perhaps a DC panel fitted somewhere to power anything that wanted DC anyway and under normal domestic use would be getting it via a device-specific transformer – e.g. laptop, phone charging, etc)?
The present setup is that we have an LPG-fired boiler for the central heating, and LPG also feeds the Aga in the kitchen. Hot water is from a cylinder, heated by the Aga (not the boiler) as well as an immersion heater which sees more use in the summer months when we switch the Aga off and thus depend on it for hot water. The immersion isn’t necessary with the Aga on unless we have guests and it needs help to reheat the cylinder quickly. The central heating is only used in the winter months as the walls are solid stone 2 feet thick. We also have a wood burner in the sitting room which means we can get away without using any central heating at all, although doing so in winter leaves the upstairs somewhat chilly.
The summer, when good solar output is available, actually coincides with when I need electrically-heated hot water since the Aga is switched off (if you don’t switch it off in summer the kitchen becomes unbearably hot).
Thoughts?
Graham wrote:
Obviously one can purchase (expensive) consumer-orientated setups with inverters, storage, etc so that it basically integrates into your existing domestic supply and you just carry on as before but now using some of your own electricity.
Most people I know use that option but add extra sockets & wiring for the “low power” things or “must be on things”, like fridge-freezer, for example, or home compute, some lighting as well.
Graham wrote:
What options are there for someone who’s happy to be more hands-on and happy to consider changes in the way they use power and/or certain appliances, hot water, etc? Someone who would prefer to purchase individual components and install them for a specific purpose (e.g. a DC immersion heater or some other water heating solution, a separate DC wiring system or perhaps a DC panel fitted somewhere to power anything that wanted DC anyway and under normal domestic use would be getting it via a device-specific transformer – e.g. laptop, phone charging, etc)?
I haven’t done it myself yet, but it’s exactly my train of thought for a future project. Lighting will certainly be DC-based. DC refrigerators available on the market are quite small, but swapping an AC motor in a regular consumer refrigerator for a DC one seems doable. Laptops may get a bit difficult as most of them operate on non-standard voltages; 12 or 24 V may well be suitable as well, but you won’t find that in the official specs. On the other hand, many power bricks will happily work when plugged into DC: some 15 years ago, I plugged a Toshiba laptop into 24 V DC instead of 230 V AC, and it worked fine.
In general, don’t forget that low-voltage DC will require much thicker wiring. On the other hand, when it comes to heating the water, by far the easiest solution is a direct solar heater. In Israel, solar heaters on the roof are mandatory in all new houses.
@Graham I live in a stone house with walls 2 thirds of a meter thick..
But one question. Are you using all the energy being produced by the AGA and the wood burner efficiently. For instance have you looked into forced air heating which could easily be combined with solar water heating especially for Spring and Autumn when in a stone house you might be using heating when the temperature outside is warmer than inside.
One advantage of the thick walled stone house is that you don’t need air conditioning even when its 40°C outside.
gallois wrote:
But one question. Are you using all the energy being produced by the AGA and the wood burner efficiently. For instance have you looked into forced air heating which could easily be combined with solar water heating especially for Spring and Autumn when in a stone house you might be using heating when the temperature outside is warmer than inside.
I think so.
I’m not aware of it ever being warmer outside than indoors during spring and autumn. Maybe on some unusually hot spring day when the temperature climbs rapidly in the morning and by lunchtime goes past the indoor temperature. At such times we would not be using the heating anyway, but the Aga would probably be on – mainly for cooking – and ‘trickle-heating’ the rest of the house. Of course in the summer it is frequently warmer outside than in and we like it like that – especially this summer just gone.
Right now we have variable weather with temperatures at max 20-21 during the day and down to about 10-11 at night. The indoor temperature does not really move from 20-21 the whole time day or night, no heating (and no Aga yet) required. I have quite a high tolerance for varying temperatures and am happy to wear sweaters indoors so don’t tend to put the heating on or light the wood burner until it’s pretty cold. The idea of living in a climate-controlled building at some ever-constant temperature is a relatively modern one I think, and I’m fine with the house being warmer in the summer and cooler in the winter. That said, the thick stone walls give far less variation that modern construction.
I would not buy an Aga. Used to live in a fair size 5-bedroom house (my ex still lives in it; all paid for by guess who 
) and the Aga was back in 1990s costing nearly £10/week in heating oil (~20p/litre then; ~95p right now). OK in the winter because you got “free” hot water (actually this is one of the oldest con tricks in “energy conservation” because hot water heating costs c. 100 quid a year, making solar domestic water heating pointless because you never recover the capital cost, and it never does useful space heating). Made the kitchen (a huge kitchen, of course; you don’t buy a “country house” with a small kitchen) too hot much of the year. Great for “heavy cooking” and especially good for the man in the house burning forgotten baked potatoes to a crisp; the smoke disappears up the chimney. They have always been high fashion for the “countryside ladies” with horses (nowadays with a Tesla too) and a 4x divorced long haul airline pilot husband but technically they are a waste of money and space. Also healthy food does not take hours to do. Fancy stodge does…
What options are there for someone who’s happy to be more hands-on and happy to consider changes in the way they use power and/or certain appliances, hot water, etc? Someone who would prefer to purchase individual components and install them for a specific purpose (e.g. a DC immersion heater or some other water heating solution, a separate DC wiring system or perhaps a DC panel fitted somewhere to power anything that wanted DC anyway and under normal domestic use would be getting it via a device-specific transformer – e.g. laptop, phone charging, etc)?
One should look at where the money actually goes. The vast majority of appliances draw just about nothing. Things like phone chargers are totally not worth even thinking about. Yes they will run off ~100V DC because their power supplies are switch-mode and designed for 110V-230V RMS AC. Next level is lights and LEDs help there a lot (less than one might think because the build quality is usually crap, so the life is perhaps 1% of what an “LED” should achieve). Then you have the harder to do stuff like properly zoning the space heating; I have always done that and it costs a fortune to install… the above “country house” had ~7 motorised valves, and my current one has 4. It does work really well. After that you get the tougher stuff e.g. a heat pump but that needs underfloor heating, and air to water is very marginal, while someone here has just been quoted 33k for a ground the water installation with a borehole.
Yes indeed, I would never buy an Aga. But it was in the house when we bought it and we like cooking with it, plus the residual heat it generates. It’s only too hot in the kitchen in June, July and August, so we turn it off. I don’t find it consumes an excessive amount of gas, not for the background heat it provides.
Removing it would cost a lot, because we’d have to replace it with something else substantial.
The really nice thing about cooking with it is never having to pre-heat an oven. You just open the door and put it in.
Peter wrote:
making solar domestic water heating pointless because you never recover the capital cost
So what is a practical and financially worthwhile use of solar panels on the roof? Does any exist?
Solar water heating – zero overall return, in nearly all scenarios.
It has kept a large number of conmen in bread and butter, ever since ~1978 when I started manufacturing the differential temperature controllers for them I did a google and found this flashback to my youth. It mentions the 802 – an unrelated product; a multizone heating controller which really did work, with self-learning optimised turn-on times, and the final version, c. 1988, did 8 zones.
The last couple of posts are possibly worthwhile of getting their own topic (Energy saving measures around the house), as the percentage of home owners among the EuroGA population is probably even higher than that of plane owners and most of us are affected by rising energy prices across Europe on way or another.
We bought our current house (detached house, 220 sqm of living space, 4-bedrooms) last summer and come September, the 20 year old central gas heater started acting up (it leaked). We had local specialist with an excellent reputation have a look, and decided to replace the unit before it became inoperable.
We looked at several alternatives. A heat pump was deemed unworkable because only half of the house was fitted with floor heating and you need that to have low-temperature heating as provided by heat pumps. For pellet heating we lacked the necessary store room for the pellets. Ultimately we decided on replacing the gas burner with a new one and combine it with a solar heating consisting of two 5 sqm panels. We recieved a German federal government grant worth a third of the costs and projections showed us saving about 10.000€ in gas over 20 years, including the initial investment of 40k€.
That was with 2021 gas prices, mind you, the savings are probably even higher right now.
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