Solar panels

[ACORN]

So how did the meeting go?

There is a multi-step approval process. We passed step 1.
We are only looking to put them on the rear side of the house. The side you can’t see from the street.
They are supposed to be working on a proposal based on that.
Waiting to hear.

 

[oldbrownhat]

...Nobody wants to mention the 'passive' methods of improving energy efficiency. I assume that is because they are a 'one and done' affair with no further profit to be made down the road. I had the attic redone to R-49 just before COVID, and the difference has been huge...

...The benefit of new windows can vary greatly depending on where you live, how many windows you have, and the aspect of the house. This house would certainly benefit, but to what degree given the outlay I cannot say. My wife's former employers (Mr and Mrs Loaded) had fantastic windows in their new build. It felt like almost no radiated heat made it through at all. I didn't ask the price, because I'm sure I could not afford it.

This ^^ Improving insulation & windows are the two things often recommended before embarking on other "active" methods. In older homes, properly sealing up the rough openings around doors & windows with low-expansion foam and making sure vapor barrier is sealed around them is one place to start. And most "green building" specialists say windows are the worst offenders of all. Even the very best high-perf windows like "Mr. & Mrs. Loaded" installed - probably coated, triple-glazed, argon-filled fiberglass frame - are probably only about R-8 equivalent The average double-glazed windows are around R 2.5 equiv.

When I built this house in 2009, the local (coastal BC) building codes required R-40 in the ceiling and vapor barrier to be sealed to the frames around doors & windows, but only specified "double-glazed windows", and they are the weakest link here. Mine are "good", but only U 0.34, which is about R 2.94 (according to this online calculator). The house is a prefab. with solid insulation EPS walls and 1.5" thermal break over the studs, so they're excellent. I have a light-coloured standing-seam metal roof but when it hit 100ºF the last 2 summers (no snickering!) I began to wonder if heat from the attic was getting into the ceiling but I measured the ceilung temp. with a thermocouple and found it wasnt an issue.

When/if I build another house, I'll use the same prefab company, but go for better windows from a local manufacturer who are LEED and Passive House certified. And I'll put in fewer windows to try and keep the costs down!

As you probably know, in UK they have been on a heat-pump binge, but with so many poorly-insulated older homes, it's very expensive because they have to improve the insulation & glazing before installing a heat pump.

 

[Farmer17]

My sister put them on her 1400sf house and she said its nice getting a $25 electric bill in the summertime but overall it was probably one of the worse decisions they ever made. She paid about $55,000 for her panel system and the roof is needing replaced and she doesn't even want to know what it will cost to remove and replace them. They were retired and debt free until the $55K system with monthly payments for many years.

 

[LVSteve]

I keep reading "replacing the roof" in many threads. Is this because the roof materials you are allowed to use because of tornadoes, hurricanes, and building codes have a limited life? Here it is concrete tile, so failing attack by a 30 lb pigeon, it deos not wear out.

 

[HOUSTON RICK]

The main problem with solar is that the technology is moving so quickly that by the time you install something it is obsolete. Similar to a computer, but the investment is a little steeper. You will be able to get something twice as good in three months, so it is hard to know where you draw the line for good enough.

 

[Jeff423]

I have solar panels which was installed free though a federally grant. The panels saves me approx $100.00 month on my electric bill. Downside is you have to sign a 25 year lease. Also here in Florida the Home Owner Insurance Companies require a new roof be installed before they will insure your house. I had to pay the solar panel company $1784.00 to remove the panels where the new roof could be installed. After the new roof was finished I had to pay the solar panel company another $1784.00 to reinstall the panels.

So you paid $3,568 plus the cost of a new roof? (I just had to have a new roof installed due to hail damage and it was about $20k.) I'm either missing something or there isn't much of a gain here. Unless your roof didn't cost much?

 

[PatriotX]

The main problem with solar is that the technology is moving so quickly that by the time you install something it is obsolete. Similar to a computer, but the investment is a little steeper. You will be able to get something twice as good in three months, so it is hard to know where you draw the line for good enough.

In my limited experience, the residental panels have been at or just over 20% efficiency for at least the last 20 years.

There is a commercial install going on at work that has panels that claim 24% conversion efficiency.

Quality and longevity is probably a greater concern at this point.

 

[LVSteve]

The main problem with solar is that the technology is moving so quickly that by the time you install something it is obsolete. Similar to a computer, but the investment is a little steeper. You will be able to get something twice as good in three months, so it is hard to know where you draw the line for good enough.

Sadly, solar panels is an area where physics has proved to be a bit of a road block to increasing efficiency. The improvements have been in small increments, nothing like Moore's Law for computers.

There is a bunch of stuff on Wikipedia and elsewhere that explains the sticking points way better than I can, but it all comes down to having a photoelectric material where the electrons get moving quickly in the presence of light. Somebody needs to brew up a new, magic, super-efficient material that is affordable. Up until now, that simply has not happened, mostly because of semiconductor physics.

 

[oldbrownhat]

...There is a bunch of stuff on Wikipedia and elsewhere that explains the sticking points way better than I can....

If you say so... One look at the NREL graph at the beginining and my eyes gave out, followed by brain cells.

"The record in real-world conditions is...held by NREL, who developed triple junction cells with a tested efficiency of 39.5%" But it seems like around 24% is the practical maximum efficiency at the moment.

 

[swsig]

Here's an article from NPR that may be useful:

Thinking about rooftop solar? 4 things to consider and how to protect yourself