Break even

Martyn1981

MFW_ASAP wrote: »

Solar stops at night and the panels are only 8% or so efficient,

Apologies for going off on a small tangent, but that 8% figure gave me deja vu, and it's taken me a day to remember why.

This quite old article looks at "efficiency snobbery", and explains why there is nothing wrong with 15 to 16%. But what I found interesting was the world map (about a 1/3 of the way down the article), that illustrates just how little area is needed to generate our leccy from PV. The map is based on 8% efficiency (hence the deja vu), rather than a more accurate 16% figure, to reflect the use of cheaper thin film PV.

Don't be a PV Efficiency Snob

Mart.

MFW_ASAP

silverwhistle wrote: »

Well, yes, and it's happening - local schools where I live, for example. But it's private individuals with the ability to quickly take decisions and act who have invested their money. We're not all rich either: my panels cost me more than 50% more than my second-hand car.

I'd also point out that even empty houses during the day can be using their own power, and hence diverting demand away from peak times, thus helping the network. I'm semi-retired, but even in the summer when working my socks off at summer school I didn't put my washing/dishwasher on when I got home!

As for your efficiency argument: no issue there either. But you'll probably find that the people who've 'blighted' their houses are also the ones who take efficiency seriously as well. My appliances are A whatever rated, most of my lights are LED now, well insulated etc. and odds are my power bills are far less than yours.

I'd take that bet, providing we exclude your PV

zeupater

MFW_ASAP wrote: »

I'd take that bet, providing we exclude your PV

... can others play this game too ?? ...

There was a time when we used around 3x the average household's gas and well over 50% more electricity .... we don't anymore & comparatively little is due to what's on the roof ...

Now, how do we want to play this game ? ... annual energy cost total ? ..or.. monthly energy cost per square meter of living space ? ....

Z

EricMears

zeupater wrote: »

Now, how do we want to play this game ? ... annual energy cost total ? ..or.. monthly energy cost per square meter of living space ? ....
Z

Results should perhaps also make an allowance for the number of occupants in the house ?

silverwhistle

MFW_ASAP wrote: »

I'd take that bet, providing we exclude your PV

Difficult to calculate really, well, with my record keeping! I tend to just look at the bottom line.

Anyway, you probably live on a boat, or summat.. But having A rated appliances, LED lights, no tumble drier and no TV means I'd still be difficult to beat, I reckon.

EricMears wrote:

Results should perhaps also make an allowance for the number of occupants in the house ?

Next you'll be wanting an allowance for having a teenager in the house!:D

zeupater

silverwhistle wrote: »

... Next you'll be wanting an allowance for having a teenager in the house!:D

... Nooooooo, please - kids don't count, adults only ..... you can't have a situation where the best way to lower the household carbon footprint is to cheat and breed like rabbits!! .... The most 'ungreen' thing you can do is make the next generation bigger than the current ....

If there are any offspring in the house take pleasure from their company (?:whistle:?), but don't try to offset the inevitable energy wastage against headcount ...

HTH
Z

MFW_ASAP

ed110220 wrote: »

'Blight' is rather a strong opinion. Fair enough solar PV can look out of place on historic homes, but is it really worse on the average home than TV antennas, satellite dishes, unsympathetic UPVC windows, mismatched and tacked on porches that don't match the house style, untidy external plumbing, wiring and all the other things we don't notice anymore just because we're so used to them? I would say it compares favourably with most of those things.

I wouldn't, I think that all of the above can be sorted out. We have our TV aerial in our loft without any problems. Satellite dishes can be attached to chimney stacks rather than stuck on the side of a house (it's just that Sky installers want to do a quick job and they're often not insured to go above the roofline), aerial wires can be moved inside the house instead of trailing all over the outside - something we have done, the vast majority of upvc windows more often than look much better than the tired wooden ones they replaced, external pluming can be internalised or tidied up - cast iron looks great, etc.

There is nothing you can do with solar panels except sit them on the roof of a house like a hat. If they are removed in decades time, the roof underneath will have a different patina than those uncovered and so the shape of the panels will be forever recorded on the roof tiles. In-roof panels look slightly better but I have heard about issues with PV overheating and roofs leaking.

silverwhistle wrote: »

having A rated appliances, LED lights, no tumble drier and no TV means I'd still be difficult to beat, I reckon.

Depends what the competition is, I thought it was to see who had the more enery efficient home, rather than who used less electricity per se? Cavemen used zero electricity but their caves could hardly be descibed as energy efficient.

In our house we have installed an insulated floor slab, underfloor heating, 100mm fibreboard internally on external facing walls, 100mm rockwool in the floor/ceiling voids, 100mm kingspan and 50mm multifoil to create a 'warm roof', airtight and high efficiency windows and the chimneys are filled with leca and we have H-shaped chimney pots (to make the woodburners more efficient). That sorts out the heating (you never mentioned this in your post, but I understand that this board is electricity-centric).

Electrically we have all LED lights, A++ rated appliances and TVs, Induction hob and we'll be buying a heat pump tumble dryer when our existing tumble dryer fails.

Only after doing as uch as we can to conserve energy would we look at generation. We have an out-building that I think will look OK with in-roof panels. If the panels are superceeded by new technology, then they can be removed and replaced with large roof windows. If the panels leak, then it's not a major problem as this is just used as a garage and a workshop.

EDIT: Almost forgot, I'm currently digging out a french drain around the periphery of the house that I'm filling with foam glass and a thin layer of decorative gravel. This will drain water away from the stone walls that could cause damp (which also makes the walls colder) and the foamglass insulation will help insulate the foot of the wall.

zeupater

MFW_ASAP wrote: »

I wouldn't, I think that all of the above can be sorted out. We have our TV aerial in our loft without any problems. Satellite dishes can be attached to chimney stacks rather than stuck on the side of a house (it's just that Sky installers want to do a quick job and they're often not insured to go above the roofline), aerial wires can be moved inside the house instead of trailing all over the outside - something we have done, the vast majority of upvc windows more often than look much better than the tired wooden ones they replaced, external pluming can be internalised or tidied up - cast iron looks great, etc.

There is nothing you can do with solar panels except sit them on the roof of a house like a hat. If they are removed in decades time, the roof underneath will have a different patina than those uncovered and so the shape of the panels will be forever recorded on the roof tiles. In-roof panels look slightly better but I have heard about issues with PV overheating and roofs leaking.

Depends what the competition is, I thought it was to see who had the more enery efficient home, rather than who used less electricity per se? Cavemen used zero electricity but their caves could hardly be descibed as energy efficient.

In our house we have installed an insulated floor slab, underfloor heating, 100mm fibreboard internally on external facing walls, 100mm rockwool in the floor/ceiling voids, 100mm kingspan and 50mm multifoil to create a 'warm roof', airtight and high efficiency windows and the chimneys are filled with leca and we have H-shaped chimney pots (to make the woodburners more efficient). That sorts out the heating (you never mentioned this in your post, but I understand that this board is electricity-centric).

Electrically we have all LED lights, A++ rated appliances and TVs, Induction hob and we'll be buying a heat pump tumble dryer when our existing tumble dryer fails.

Only after doing as uch as we can to conserve energy would we look at generation. We have an out-building that I think will look OK with in-roof panels. If the panels are superceeded by new technology, then they can be removed and replaced with large roof windows. If the panels leak, then it's not a major problem as this is just used as a garage and a workshop.

EDIT: Almost forgot, I'm currently digging out a french drain around the periphery of the house that I'm filling with foam glass and a thin layer of decorative gravel. This will drain water away from the stone walls that could cause damp (which also makes the walls colder) and the foamglass insulation will help insulate the foot of the wall.

Hi

Looks good and it's the right way to go ... get the energy requirement right down, then look at energy provision - I really despair when people justify expenditure against a high energy requirement only to reduce the requirement later ....

Anyway, regarding 'Depends what the competition is, I thought it was to see who had the more enery efficient home, rather than who used less electricity per se?' .... I'd say that many on these boards would agree, I certainly do & that's why the recent posts have mentioned total energy and go on to find a fair way of comparing properties of different sizes (and potentially different levels of occupation) ... should we also compare food miles, fuel miles, personal transport etc ?? ... I don't know anybody else's thoughts on this, but maybe a carbon footprint calculator could standardise the comparison methodology ... Last time I used the 'Act on CO2' calculator our footprint was somewhere around 10% of the UK average using their methodology, which I guess would take some beating by anyone ... What I'm trying to convey is that just because the majority of 'conversations' on these threads sway towards pv, it's probably more than a little misguided to believe that other efficiency measures haven't also been addressed ...

HTH
Z

silverwhistle

zeupater wrote: »

What I'm trying to convey is that just because the majority of 'conversations' on these threads sway towards pv, it's probably more than a little misguided to believe that other efficiency measures haven't also been addressed ... Z

Indeed! My efficiency could be a bit better - my back door probably needs replacing but that will be part of replacing steel lintels etc etc, so will have to wait whilst I save..

I've had cavity wall insulation since the 80s, double glazing before that to avoid the ice on the inside of the Crittal windows, and good roof insulation, including insulation/boards/celotex/boards for my storage areas in the loft. PV makes sense though, because the return is the best I could hope for for that amount of investment.

On the heating front I haven't yet had the central heating on this year due to the new wood-burner. All free wood, of course, although I admit I've bought some briquettes for emergencies and to avoid faff when aged parent visits.

There's not much else I can do with my particular income and circumstances, although MFW_ASAP has certainly done a good job. But I still think we should think about what we use: not having a TV is choice for me and no way due to keeping energy use low, and I've no need for a tumble dryer. But I could have the most efficient car and still use it inappropriately, or have the lowest consumption Christmas lights all over my house lighting up the road.:D

My own particular guilty energy secret is being a skier, but as I used to live over there my visits are reasonably low cost.. I'm very aware of global warming: most of the resorts in the area I used to live in have already had two postponements of their openings due to lack of snow and high temperatures.

Smiley_Dan

It becomes a question of what your goals are. PV makes a lot of financial sense. But for carbon reduction it's often your space heating you need to look at, and cavity wall insulation (unless you have enormous cavities) doesn't really cut it.

In your case, burning scrap wood, maybe less so. But the wood would go further with more insulation.