Are Solar Panels really worth it?

Select to expand quote

musorianin said..
....Unlike a timer, a diverter only sends power to hot water when it is available from PV. On the odd occasion you don't get enough solar in a 24 hour period you can override. I've had to do that less than a dozen times since install a year ago. Converts your hot water into a kind of battery, so to speak.

Don't you want both?

You don't want any PV energy going into the hot water if it's a sunny day and it's going to heat up anyway, and/or if you're not going to need hot water during that time.

My solar hot water gets boosted towards the end of the day to top up the temperature after a day of sun, and a boost just before were get up to make sure we have hot water for showers and stuff and to top up anything used the evening before. True the morning boost is a little redundant but the missus wouldn't be happy if the morning shower wasn't properly hot.

In the depth of winter I extend the morning boost so that the hot water is topped up after the morning showers. If I don't there a chance we don't have hot water during the day. The only real need for hot water in winter is I go out for a session almost every afternoon and I like to take a bottle of hot water to rinse down with afterwards.

Select to expand quote

Gorgo said..

musorianin said..
....Unlike a timer, a diverter only sends power to hot water when it is available from PV. On the odd occasion you don't get enough solar in a 24 hour period you can override. I've had to do that less than a dozen times since install a year ago. Converts your hot water into a kind of battery, so to speak.

Don't you want both?

You don't want any PV energy going into the hot water if it's a sunny day and it's going to heat up anyway, and/or if you're not going to need hot water during that time.

My solar hot water gets boosted towards the end of the day to top up the temperature after a day of sun, and a boost just before were get up to make sure we have hot water for showers and stuff and to top up anything used the evening before. True the morning boost is a little redundant but the missus wouldn't be happy if the morning shower wasn't properly hot.

In the depth of winter I extend the morning boost so that the hot water is topped up after the morning showers. If I don't there a chance we don't have hot water during the day. The only real need for hot water in winter is I go out for a session almost every afternoon and I like to take a bottle of hot water to rinse down with afterwards.

Hi, I can't help but wonder if water heated from the sun may be more economically done with a slightly larger solar array than a separate solar hot water system.
This is assuming that there is a pv system, if not then the solar hot water system works.

Select to expand quote

Gorgo said..
I just got 4 quotes for solar panels, then decided to put the process on hold while I think about how it's all going to work.

It is going to work like this :

1) professional salespeople who spend 40 hours a week for twenty years selling stuff to people are going to sell you a dream that solar panels are the solution to all your problems
2) you agree that solar panels must be the answer to all your problems, why haven't you realized this already, and you pay these people lots of money for something you don't really understand
3) you don't really understand it because the salespeople have convinced you it is quite complex and that's why it is a lot of money, but don't worry because as you are paying a lot of money you don't have to understand it because you have paid a lot of money so somebody else can understand it for you
4) they give you a great 4 year warranty, that is all you need, they will tell you so
5) after 4 1/2 years the whole thing stops working
6) you obviously have no claim for warranty, it is plain-as in the original agreement, didn't you understand the technical limitations ? why did you pay so much for something you didn't really understand ?
7) you can't get it fixed because that technology is so out of date and these new systems are so much better, best thing is to scrap what you have and buy a whole new, much better-er system that will be the solution to all your problems
7) you wonder if there is any link between being able getting a seven year unlimited warranty on a petrol car with complex moving parts that rub and wear and a simple PV array with solid state electronics that only offer a 3 year warranty. You assume you must be dumb because obviously inefficient solar energy and big heavy very inefficient batteries are the answer to everyone's problems - so says everyone.

8) it will all be irrelevant because in 5 years time you will have a EV in the garage 90% of the time with a broken battery that cost loads more than the two broken PV systems on your roof did, and it is also old tech that is out of warranty. And you can still fall back to using the electricity coming from the cables from the coal-fired power plant, and your old V8 landcruiser.

Select to expand quote

Gorgo said..

musorianin said..
....Unlike a timer, a diverter only sends power to hot water when it is available from PV. On the odd occasion you don't get enough solar in a 24 hour period you can override. I've had to do that less than a dozen times since install a year ago. Converts your hot water into a kind of battery, so to speak.

Don't you want both?

You don't want any PV energy going into the hot water if it's a sunny day and it's going to heat up anyway, and/or if you're not going to need hot water during that time.

My solar hot water gets boosted towards the end of the day to top up the temperature after a day of sun, and a boost just before were get up to make sure we have hot water for showers and stuff and to top up anything used the evening before. True the morning boost is a little redundant but the missus wouldn't be happy if the morning shower wasn't properly hot.

In the depth of winter I extend the morning boost so that the hot water is topped up after the morning showers. If I don't there a chance we don't have hot water during the day. The only real need for hot water in winter is I go out for a session almost every afternoon and I like to take a bottle of hot water to rinse down with afterwards.

I don't have solar hot water, just electric.

From that link

Green CATCH is best suited to these situations;
Those who don't have the internet

This I don't understand. How is "The Internet" involved in switching your water heater on?

Lots of different opinions on here, but it really depends on your own personal situation.
The one thing that a PV system with monitoring can help with, is being able to constantly see how much power you are using / producing, which can help you make decisions to reduce your daily energy cost.

I was lucky enough to be in the position to recently built a highly efficiency house.
15 years of research and planing, with a lots of informed decisions being made about the thermal performance / energy required to heat and cool it. It is all electric and we have a 10kW of PV all facing North and unobstructed.
We have a Sanden heat pump for Domestic hot water and a different one for in slab hydronic heating. No aircon.

Our predicted electricity bill is going to be about $700/pa. This is for all of our energy and our thermal comfort in the house is high.
FIT is $0.10 cents, import is about $0.21 cents and a daily charge of $1.20

We also have a mid size EV as a daily driver (About 50km per day). This can be charged only by solar as the unit knows when you have excess, or it can also be charged over night when the tariff is less if needed (Grid demand is lower), or a combination of both.
(Don't worry I still have a diesel van for windsurfing... but I much prefer to drive the EV, it so much fun!)

I believe reducing your energy needs and producing your own it is a wining combination.
Sort of like eating the veggies you have grown, drinking the beer you have brewed. There is great satisfaction in it.
You become obsessed with your excess solar and what you can use it for.

Home batteries are still evolving and I am going to wait for this to settle a bit as the payback time will be awhile at our current $700 / year power bill. I also have no need / desire to go "off grid". Although, now there are Virtual Power Plant schemes where if you buy a battery from them, they will pay you 40c/ kW for any excess power you send back to the grid during peak times.

So, is PV worth it? For me, yes I think so.
For you? You will have to study it a bit and make an informed decision on if it is worth it for you.

Or, get the builder to improve the star rating of your house with better windows / insulation, as that will be a benefit for the life of the building. Just get them to provide the cabling for the PV, then get it installed after handover when you can afford it.

It has been a really nice few days for PV down here in COVID VIC
Here you can see where the DHW finished heating at around 2pm.

Select to expand quote

Paddles B'mere said..
Loving your work Gav, we did the same ............. but 12 years ago. It means you cough up a little more CAPEX up front (from an investment perspective) but save money on the OPEX in the long run.

Thanks. Yep, the upfront is more, was about 15% with lots of people asking abut the ROI
For this house, I did not care about the ROI as it should be the last one I build and, how do you put a price on comfort?
Maybe we should be building houses 15% smaller to cover the cost of energy efficient building methods....

Why not take the free solar as well? In 5 years time, you would have passive income, and the fact it is being installed as part of a new build means you should avoid most of the potential problems of having solar installed on an existing house.

The insulation will mean any heating or cooling is super efficient, so you'll have more power to sell back to the grid. Hard to see the downside.

Setting up (or designing) a house to not need a/c is a pretty good passive solution Storm Ahead, especially if you have access to sea breezes like we do along the SEQ coastal fringe. Houses here in Australia are generally built to a price to satisfy the property speculators and are rarely built to be energy efficient for the long term (and energy efficient houses are rarely built by project builders).

But traditional house design uses cross ventilation for cooling. Try leaving your windows open day and night up there in Qld and your house might be cool, but all your riches will be migrating to the local pawn shops.

@MM .............. that's why we used a combo of louvered windows and security screens so we could make the whole house a breezeway in summer and keep the grubs out (if they want to get in bad enough they can still smash their way in anyway but what do ya do?)

@StormAhead .................. please tell me you resisted "fashion" and got a reflective colourbond finish colour like "Surf Mist" .............. I cringe when I see houses with dark/black roofs and fascias/gutters. Spend the money and get the widest eaves you can buy to shade your walls for as long as possible.

@cisco ........... yep, sensible design can solve a lot of issues

Select to expand quote

Paddles B'mere said..

@StormAhead .................. please tell me you resisted "fashion" and got a reflective colourbond finish colour like "Surf Mist" .............. I cringe when I see houses with dark/black roofs and fascias/gutters. Spend the money and get the widest eaves you can buy to shade your walls for as long as possible.

the black / dark grey roof + white wall for everything had been a trend for almost 10 years here on the gold coast, particularly by reno / flippers. It will probably soon be considered the pink-and-grey of the late 1980's now the terracotta trend seems to have started

Select to expand quote

Ian K said..

Mr Milk said..
But traditional house design uses cross ventilation for cooling. Try leaving your windows open day and night up there in Qld and your house might be cool, but all your riches will be migrating to the local pawn shops.

I suppose after a while you get used to it and don't notice. But those of us who live in houses where the doors and windows are always open do. Why not one internal strong room if you keep stuff of value?

The other problem with open windows in suburbia is your neighbours' appalling taste in music. My current lot think that rap should be shared with the world I think, yes, tongue twisters are fun, but don't you play that game with children and let it go?

Here's a PV related question for the 'breeze brain trust, hoping it's not already buried too far...
I had my PV system installed soon after purchasing my property in 2012.
1.5 Kw of Northish facing panels tied to a 2Kw inverter.
Can I throw up a couple more PV cells facing west to catch more sunlight through the afternoon? Will excess solar "production" degrade or overheat the system? Will 'the Man' be upset?

Select to expand quote

Paddles B'mere said..
Check your contract with "The Man" .................. if it states 2kW for grid connection then go for it, if it states 1.5kW then be wary.

Roger!