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We are considering adding solar to our roof. The south side of our roof is the largest, and has an unobstructed view of the sun for the majority of the day, from roughly 9am until 7pmish during the summer.

Any thoughts on what we could potentially expect to pay for solar, if possible we would like to have a system that will generate enough to offset most or all of our consumption.

In summer 2015, pre volt, we consumed at our peak 2,729 kWh in July.

Are residential solar systems capable of producing this much power?
 

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We are considering adding solar to our roof. The south side of our roof is the largest, and has an unobstructed view of the sun for the majority of the day, from roughly 9am until 7pmish during the summer.

Any thoughts on what we could potentially expect to pay for solar, if possible we would like to have a system that will generate enough to offset most or all of our consumption.

In summer 2015, pre volt, we consumed at our peak 2,729 kWh in July.

Are residential solar systems capable of producing this much power?
If you do the math. kWh used in July/ number of hours of sunshine in July = rough idea of how big the solar array would need to be.

That will get you a starting point at least.
 

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There is a site, pvwatts, that can help with possible production, it gives results by month and takes local weather into account.
http://pvwatts.nrel.gov/pvwatts.php

There are a couple things you need to know first:
1) what will the utility do for you if anything.
2) what is the utility net metering plan. (maybe the most important item)
3) It is always and I mean always cheaper to conserve a watt than to generate a watt.
4) The cheapest way to do solar is grid tie system, which has no batteries. They only work while the utility is up.
5) Get one years worth of utility bill data out and make a spreadsheet of your consumption.

Actually the above recommendation for July consumption is way to generic. There is no way I would have enough roof space for panels to offset my August consumption which last year was 4 megawatts (4180 kWh). We only generated about 1800 kWh that month but we got to use net metering credit from the spring to offset a major remain chunk of that 4180 kWh. If the net-metering plan is consumer friendly you might do better, as in the California plans where a kWh generated during a peak price period is credited as a $$$ amount and can be used to offset the purchase of night time power (sometimes at 5 to 1 difference in price).

Installation prices are constantly falling, around $3 a watt installed for grid tie should be pretty reasonable, of course YMMV.
 

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Discussion Starter #4
If you do the math. kWh used in July/ number of hours of sunshine in July = rough idea of how big the solar array would need to be.

That will get you a starting point at least.
Yea... its a pretty rough starting point... I started doing some math which is probably very wrong.

At our peak, we would use approximately 91kWh per day, if the average panel can crank out 200 watts, that means it takes 5 to crank out 1kWh.

That means to cover that peak month, we would need 65 panels on the roof.

I'm not sure our home is capable of holding that many, OR that it would be in our budget / financing ability.

Our power company will let us buy blocks of solar in their solar farm for $25 per block... I might buy 1, they claim to put out about 400kWh per month. That would be enough to offset the car every day.
 

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If your Electric utility Cie has net metering, where you can send unused kWh back to the grid, and have credit for using more than you can produce at other times, gather your yearly consumption.

Once you know how many kWh you use yearly, check the exact orientation of your roof (degrees from North, south is 180) you can use Google earth for that.
Also try to figure out the approximate slant of your roof (many are 20 degrees)

Then go to the web site below
http://pvwatts.nrel.gov/

Enter your address

Then go to system info (right arrow on the right)

By default it will be set for a 4kW DC size system (Array panels power). If your roof is full south, the default azimuth of 180deg is right, if not change it to the correct value. Change the roof tilt if not 20 deg.

Then click the Right Arrow to Go to PvWatt results.

This will give how many AC Energy (kWh) a 4 kW Array will produce on your roof. If the total is less that your yearly consumption, go back and change the initial "DC size system" for 4 (kW) to something bigger or smaller, and do that until the array produces a total AC Energy (kWh) for the year that matches your consumption.

That will tell you approximatly how big of a solar panel array you need.

Then estimating how much that will cost you depends a lot on your local installers. A good price these day would be right under $4 per Watt. So if you need a 4kW array, that would be $16,000 before incentives.
But my experience is that it can prove difficult to find an installer that will do it for that price, and you will more likely be in the $5 to $6 per watt or more... for a 4kW array around $20,000 to $24,000.
Remember that you do get 30% of that off in federal tax credit and you may have other local incentive.
 

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We are considering adding solar to our roof. The south side of our roof is the largest, and has an unobstructed view of the sun for the majority of the day, from roughly 9am until 7pmish during the summer.

Any thoughts on what we could potentially expect to pay for solar, if possible we would like to have a system that will generate enough to offset most or all of our consumption.

In summer 2015, pre volt, we consumed at our peak 2,729 kWh in July.

Are residential solar systems capable of producing this much power?
Forget July and look at your yearly consumption then you will know how large of an array you need. An easy off the hand math is to simply estimate 1 panel=1KwH per day. Nothing wrong with putting an array on your roof, but if there is space, consider one in your yard instead as it will keep things cooler and increase overall production. I suggest doing it yourself, but if you are not inclined to do so, I understand. I suggest this setup either way.

Solarworld panels (they are considered the best as they basically never fail and most are made right here in USA)
Ironridge rails (they are incredibly strong and are made here as well)
Enphase microinverters (they are outstanding and provide many benefits even if shading isn't an issue...designed in USA, but made in China)

Pricing will vary by region, but you could expect to pay around $450-$500 per panel (total cost including everything you need) if you do the work yourself using the materials I suggested above which is REAL quality. This is before any tax incentives. If you price the work, make sure it is a fair comparison as you can go much cheaper if you use Chinese panels, inverters, rails...
 

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Discussion Starter #7
There is a site, pvwatts, that can help with possible production, it gives results by month and takes local weather into account.
http://pvwatts.nrel.gov/pvwatts.php
Thank you solar_dave! That is a fantastic site. It easily let me estimate based based on my roof from google maps! I hadn't taken into consideration any excess power sold back in other months.

Our electric co-op does net metering, but pays WAY less for any additional power we generate than what they charge for consuming it.

We have different rates for summer/winter. We can expect to pay about $0.154 per kWh in the summer and about $0.825 per kWh in the winter.

They buy back excess power generated at $0.042 per kWh.

Based on the estimates of that site, and our use patterns I could expect some credits 8 months out of the year.
 

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After 7 years of owning solar here is what I have seen.....

Each KW of solar produces (on average) 150KWH per month. My 3KW system averages 450 KWH per month. It varies by season, but not dramatically.

So to try to fully offset your peak usage of 2700 KWH you would need an 18 KW system. That is clearly more than your roof can handle.

You may want to set a lesser goal. Perhaps look at your off peak months and see if you can offset that usage. To offset the Volt, you need about a 1.5 KW system (+/-).

I'm out of touch on cost, so I'll let others speak to that...
 

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I agree with the others suggesting that you not try to size your system to meet your peak monthly demand. Since you pointed out that your utility will only pay you a fraction of the retail price per kWh for excess power, I would think you would want to size it to significantly less than your peak demand in order to avoid excess production during non-peak months. (Not to mention the fact that you'd need a HUGE array to produce 2,729 kWh in a single month.)
 

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All good advice and the Federal Tax Credit of 30% is a real cost saver at tax time, but I believe the credit stops this December so don't delay...
 

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Yea... its a pretty rough starting point... I started doing some math which is probably very wrong.

At our peak, we would use approximately 91kWh per day, if the average panel can crank out 200 watts, that means it takes 5 to crank out 1kWh.

That means to cover that peak month, we would need 65 panels on the roof.

I'm not sure our home is capable of holding that many, OR that it would be in our budget / financing ability.

Our power company will let us buy blocks of solar in their solar farm for $25 per block... I might buy 1, they claim to put out about 400kWh per month. That would be enough to offset the car every day.
Well it probably varies alot with site and specific equiptment. My 35 panels can deliver 50 KWh/day or so at this time of year. So that number isn't too far off.
 

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Our power company will let us buy blocks of solar in their solar farm for $25 per block... I might buy 1, they claim to put out about 400kWh per month. That would be enough to offset the car every day.
Several power companies in Ohio started offering 100% renewable (Wind and Solar) energy plans. I recently changed to one of these and actually lowered my generating rate per kWh.
 

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I think there are so many variables from location to location you will need to check with a couple of local solar installers, or your electric utility. Different utility companies deal with net metering in different ways. The info you receive here might not be accurate for your area.
 

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I am shocked and confused by your statement that you consume 2,729 KwH of electricity monthly. My personal consumption is 100 KwH at home and 125 KwH for my 2013 Volt each month. I wonder whether you actually mean that you consume 273 KwH monthly. Otherwise, I think that you should first consider conservation before building new solar infrastructure. Furthermore, if you are interested in constructing a parking shelter for your Volt, you can install a charging station for around $47,000 from Envision Solar (EVSI) http://www.envisionsolar.com/.
 

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I am shocked and confused by your statement that you consume 2,729 KwH of electricity monthly. My personal consumption is 100 KwH at home and 125 KwH for my 2013 Volt each month. I wonder whether you actually mean that you consume 273 KwH monthly. Otherwise, I think that you should first consider conservation before building new solar infrastructure. ...
I am shocked and confused by your statement that you ONLY consume 100 KwH of electricity monthly.

We probably use 100KwH per month on any/each of the following:

- charging 4 cellphones and two tablets,
- washer and dryer which seem to run constantly,
- pool pump
- lighting up rooms no one has been in for over an hour
- air conditioning a large suburban home when the temps and humidity are 90 and 90 for several months a year.
 

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I too was a bit taken aback by your usage, but since you indicated peak usage in July I assumed it was a hot place.
Air conditioning can really suck up electrons. We have it but rarely use it thanks to our moderate climate.
electric dryers really suck up the power as well

But one thing you may be able to do is change all your lights to LED's.
The power consumption is only about 10% of that of an incandescent and lower than compact fluorescents as well.
One of my friends spent $2000 on LED bulbs and knocked $100 per month off his electric bill.
We made room for our volt by changing from mostly incandescents to all LED's.
With the LED's it hardly matters if you remember to turn them off.

On the benefits of solar it also depends on whether you have a tiered pricing structure.
Here in CA tier 4 is more than twice tier one and its not that hard to hit tier 4.
So some folks put in solar just to get into the lower tiers.
 

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The average U.S. power consumption per month is about 900 kWh, so a peak of 4,000 kWh in the hottest month of the year is high but conceivable. As others have stated, the first priority should be conservation. Do you know what your big power draws are? Do you have a pool with pump? Do you have an inefficient clothes dryer (a heat-pump clothes dryer will pay for itself very quickly)? Do you have single or out-dated double-pane windows? Have you switched to LED lighting? Even in the most harsh climates, it would be very difficult to have a peak monthly usage of 4,000 kWh in a LEED-certified/energy efficient home.

I've been debating the size of solar array I want to put up for my family, but I've settled on on enough to cover the > Tier 1 consumption in peak months and total consumption in off-peak months. For my family, that amounts to a 3 kW array. I might go 4 kW just because we will probably be transitioning to full electric (dropping the LPG), and I will likely give my mother my Volt.
 

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The average U.S. power consumption per month is about 900 kWh, so a peak of 4,000 kWh in the hottest month of the year is high but conceivable. As others have stated, the first priority should be conservation. Do you know what your big power draws are? Do you have a pool with pump? Do you have an inefficient clothes dryer (a heat-pump clothes dryer will pay for itself very quickly)? Do you have single or out-dated double-pane windows? Have you switched to LED lighting? Even in the most harsh climates, it would be very difficult to have a peak monthly usage of 4,000 kWh in a LEED-certified/energy efficient home.

I've been debating the size of solar array I want to put up for my family, but I've settled on on enough to cover the > Tier 1 consumption in peak months and total consumption in off-peak months. For my family, that amounts to a 3 kW array. I might go 4 kW just because we will probably be transitioning to full electric (dropping the LPG), and I will likely give my mother my Volt.
Great post, Ladogaboy.

I can't believe Solar_Dave let the conservation part go unmentioned.:rolleyes:

We were able to shed ~30% of our pre-array usage before installing solar. We're in a climate more similar to the OP than all but a few that have commented. Our A/C load is unavoidable for us. (Edit: it's 79* @ 6:10 AM right now with a "Feels Like" of 82*) But we were able to mitigate our loads in other areas. Radiant barrier decking was installed when new shingles were installed - pre-array - along with 98% LED bulbs and CFL's where LED equiv. is not available/desired for a particular fixture just to name a few upgrades.

Our 56-panel array has equaled/surpassed our usage - including ~350 kWh/month for our Volt - for around 6 months every year. In 3.5 years of operation we've produced 995 kWh less (as of yesterday) than we've consumed.

Here's my online spreadsheet of our production/usage. Because of the way our utility does net-metering, we've paid them $710.55 since the array went live.

Again, conservation pays you back faster than solar. Solar is the icing on the cake after you've cleaned up your usage habits the best you can.
 

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Great post, Ladogaboy.

I can't believe Solar_Dave let the conservation part go unmentioned.:rolleyes:

We were able to shed ~30% of our pre-array usage before installing solar. We're in a climate more similar to the OP than all but a few that have commented. Our A/C load is unavoidable for us. (Edit: it's 79* @ 6:10 AM right now with a "Feels Like" of 82*) But we were able to mitigate our loads in other areas. Radiant barrier decking was installed when new shingles were installed - pre-array - along with 98% LED bulbs and CFL's where LED equiv. is not available/desired for a particular fixture just to name a few upgrades.

Our 56-panel array has equaled/surpassed our usage - including ~350 kWh/month for our Volt - for around 6 months every year. In 3.5 years of operation we've produced 995 kWh less (as of yesterday) than we've consumed.

Here's my online spreadsheet of our production/usage. Because of the way our utility does net-metering, we've paid them $710.55 since the array went live.

Again, conservation pays you back faster than solar. Solar is the icing on the cake after you've cleaned up your usage habits the best you can.
Go back and read it again Norm! LOL :D:D:D

3) It is always and I mean always cheaper to conserve a watt than to generate a watt.
 
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