On Wednesday, August 16, 2017 at 9:50:04 PM UTC-4, micky wrote:
In alt.home.repair, on Wed, 16 Aug 2017 15:52:33 -0700 (PDT), trader_4
wrote:

On Wednesday, August 16, 2017 at 5:04:17 PM UTC-4, micky wrote:


How much sun does the north side of a roof in your area get
even in summer?

Whatever Derby Dad's page said.

It's not about summer just summer
months, it's about how much sun falls on a given roof face
during the entire year.

It depends on what you mean by "it". You appear to be talking about the
annual solar input, but I was talking about "The sun is overhead in the
summer".

Do people typically buy these systems based on it's output versus
it's cost savings based on the summer only or on a whole typical
year?

Let me say again, I wasn't talking about annual output or how people
decide whether to buy solar panels or not.

I was talking about "The sun is overhead in the summer". If you want to
call it thread drift or OT, feel free.






South facing is best, sw is still
very good. North, forget about it. I've never seen an array
facing north, have you?

I have. Did you read Dad's page. It's not such a bad idea,depending on
the latitude and slope of the roof, and maybe there were other factors.

I just read it now. Let's start with this:

How much worse are north-facing solar modules?

"We start with a typical residential system in Charlotte, North Carolina. We designed and modeled the system in HelioScope, our sales and design software platform. With a 2/12 pitched roof...."


So, they don't start with a "typical residential system", unless 2/12
roofs are typical in NC. Are they typical in MD? They aren't typical
here, 6/12 would be typical. Then they say that if it were a shallow

Now you are talking about roof pitch when I was asking your question
about whether I had seen an array facing north. As I said, I have seen
it and it's not such a bad idea, depending on atleast 3 factors.

If you want to change the subject, fine, but I think you should make
clear that you're not relating your new topic with my topic.

I am relating it to your topic. You said someone in your
neighborhood got solar panels installed. That was the topic.
Seems to me that system, the economics of it, whether it's wise
to install or not depends on using it year round, not just during
the summer. You apparently then swallowed that article about north
facing roofs not affecting performance much without realizing they
start off with a very misleading analysis, they use a 2/12 roof and
then say that it gets even better with a low pitch roof, 1/12?
2/12 is already a low pitch roof, the lowest code allows for shingles,
but then they want to sell solar systems, so they probably aren't
the most objective, eh?

The problem is that solar is only feasible for most people because
it's being subsidized, it has a long payback period and when you
further cripple it by putting
it on a north facing roof, it gets worse, a lot worse if it's
a typical 4/12 to 6/12 roof instead of a nearly flat roof in the example.






But since you've changed the subject, yes, there are 2/12 roofs here.

Probably some 1/12 roofs but I don't remember any in particular.

On homes here, a 2/12 roof isn't common, I've never seen a 1/12
roof. And where I have seen a 2/12 kind of roof, it's been as
just one smaller part of an overall structure, like part of a
contemporary house design. I have one roof plane close to that
on mine, over the garage, but it's not big enough for a typical
array either.

If you want to put a solar array facing north and understand the
economics, that's fine. I'm just saying if you read that article
where they claim to use a "typical" installation and then use
a 2/12 roof and talk about a 1/12 roof, to show that the output
only takes a 16% hit, it's very misleading. Eventually they do
say that a more typical 4/12 roof takes a 29% hit, which is why
you don't typically see them on the north side of homes. It
changes the economics significantly.