Solar hot water heater

I'm cross posting from Alt Energy Renewable because I haven't got an answer yet.
Hello all you solar guru's :-)
I'm in Phoenix AZ and am about to take the plunge and replace my standard electric hot water heater with a solar system. I think I have decided on the system manufactured by Fafco sungrabber.com for those that don't know about them. I have had two companies come out so far to give me estimates and the differ by about $2000 and they are both Fafco systems. For those of you that are running a solar setup like this I have a couple questions. The first quote I got was for a 4 panel system and a 80 Gal tank and the second quote I got was for a 2 panel system and a 60 Gal tank. This is a family of four and we currently have a 50 Gal electric hot water heater. Would you say a 2 panel is enough or are we going to need the 4 panel setup? Secondly do any of you have a system by this company and would you recommend them? Lastly on figuring out the yearly savings of a system like this would my calculations be pretty close? I have APS for electric and over the last year I averaged that we pay .10/kWh. My Current hot water heater based on the Energyguide sticker uses about 5100kW per year. If the new system will only use about 2300kW per year then I should save about $280 per year
Cheers, Chris

On Tue, 25 Nov 2008 14:01:33 -0800 (PST), Chris wrote:

I'm cross posting from Alt Energy Renewable because I haven't got an answer yet.
Hello all you solar guru's :-)
I'm in Phoenix AZ and am about to take the plunge and replace my standard electric hot water heater with a solar system. I think I have decided on the system manufactured by Fafco sungrabber.com for those that don't know about them. I have had two companies come out so far to give me estimates and the differ by about $2000 and they are both Fafco systems. For those of you that are running a solar setup like this I have a couple questions. The first quote I got was for a 4 panel system and a 80 Gal tank and the second quote I got was for a 2 panel system and a 60 Gal tank. This is a family of four and we currently have a 50 Gal electric hot water heater. Would you say a 2 panel is enough or are we going to need the 4 panel setup?

Hot water consumption is extremely variable owing to differences in family habits. For example, a single individual taking long showers could use more hot water than a thriftier family of four. Therefore it would be better to quantify how much hot water you actually use. Perhaps by putting a water meter on the inlet line of your current tank.

Secondly do any of you have a system by this company and would you recommend them?

Don't know them, but their setup seems reasonable. Here's an outfit from which I've purchased copper collectors at a competitive price http://www.sunraysolar.com/index.php. They sell complete systems as well, you could compare their prices with your quotes so far.

Lastly on figuring out the yearly savings of a system like this would my calculations be pretty close? I have APS for electric and over the last year I averaged that we pay .10/kWh. My Current hot water heater based on the Energyguide sticker uses about 5100kW per year. If the new system will only use about 2300kW per year then I should save about $280 per year

The rating on that sticker is somewhat useful for comparing one conventional heater to another, but not much good for the purpose at hand. If you knew how much hot water you were using, you could make an indirect but reasonable estimate of your current heater's energy consumption. Better would be to install an energy meter on the power line to your tank. There are several ways to do that, if you're interested then there a few here who can make recommendations. In the meantime, here's a $140 device that would do the job http://www.theenergydetective.com/store. You could install it on the water heater circuit to get the info you need now, and later move it to your main supply. After that all :-) you'll need to make a good estimate of the savings is a reliable number for the new system's performance.
Wayne

wrote in message

On Tue, 25 Nov 2008 14:01:33 -0800 (PST), Chris chris.holub@gmail.com> wrote:
I'm cross posting from Alt Energy Renewable because I haven't got an answer yet.
Hello all you solar guru's :-)
I'm in Phoenix AZ and am about to take the plunge and replace my standard electric hot water heater with a solar system. I think I have decided on the system manufactured by Fafco sungrabber.com for those that don't know about them. I have had two companies come out so far to give me estimates and the differ by about $2000 and they are both Fafco systems. For those of you that are running a solar setup like this I have a couple questions. The first quote I got was for a 4 panel system and a 80 Gal tank and the second quote I got was for a 2 panel system and a 60 Gal tank. This is a family of four and we currently have a 50 Gal electric hot water heater. Would you say a 2 panel is enough or are we going to need the 4 panel setup?
Hot water consumption is extremely variable owing to differences in family habits. For example, a single individual taking long showers could use more hot water than a thriftier family of four. Therefore it would be better to quantify how much hot water you actually use. Perhaps by putting a water meter on the inlet line of your current tank.
Secondly do any of you have a system by this company and would you recommend them?
Don't know them, but their setup seems reasonable. Here's an outfit from which I've purchased copper collectors at a competitive price http://www.sunraysolar.com/index.php. They sell complete systems as well, you could compare their prices with your quotes so far.
Lastly on figuring out the yearly savings of a system like this would my calculations be pretty close? I have APS for electric and over the last year I averaged that we pay .10/kWh. My Current hot water heater based on the Energyguide sticker uses about 5100kW per year. If the new system will only use about 2300kW per year then I should save about $280 per year
The rating on that sticker is somewhat useful for comparing one conventional heater to another, but not much good for the purpose at hand. If you knew how much hot water you were using, you could make an indirect but reasonable estimate of your current heater's energy consumption. Better would be to install an energy meter on the power line to your tank. There are several ways to do that, if you're interested then there a few here who can make recommendations. In the meantime, here's a $140 device that would do the job http://www.theenergydetective.com/store. You could install it on the water heater circuit to get the info you need now, and later move it to your main supply. After that all :-) you'll need to make a good estimate of the savings is a reliable number for the new system's performance.
Wayne

Regarding monitoring the electricity used by the water heater, I purchased a watthour meter on ebay. The cost was $8.00-- plus $13.50 for shipping. Anyway I have had it installed for 24hrs and it reads 23 kwh. My per kwh cost is 10.4 cents, so that is $2.40 cents. I hope this first day is just a high use day. I'll have a better measure in a month or two. Here's a link to one, about $20.00 now. http://cgi.ebay.com/200-AMP-WESTINGHOUSE-WATTHOUR-METER_W0QQitemZ180308738881QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item180308738881&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A15|39%3A1|240%3A1318

I think the idea is get the big tank, because as you use hot water in the evening, the incoming cold brings the avg temp down. If you could shut off the cold water input when the collector wasnt pumping, and use compressed air or something to squeeze the remaining hot water out the pipe, it would stay hot right down to the bottom.

"BobG" wrote in message On Dec 7, 10:37 am, "amdx" wrote:

It's been two weeks since I put the watthour meter on my water heater. Average daily electricity cost to heat water is $1.77. Family of four, two teens. ======================================================

Hi Mike, Can you tell us 1)how long a tank full of hot water will sit and hold its heat with no hot water use until the element comes on and 2) how long it comes on to top off the heat in the tank. It might be hard to get everyone to not use any hot water for an hour or two, but I wonder exactly what the 'maintenance' energy consumption is to keep it hot in the tank. The cost to heat up the incoming cold water is the same for the tank and tankless versions, so this small 'keep it hot' cost is the theoretical savings from the tankless models.
I didn't get 100% precise times, but a good ballpark. My daughter finished her shower about 6:25. The meter stopped just before 7:00 There was 1/4KWH used before 8:00 There was 1/2 KHW used before 12:15 There was 1/4 KWH used before 3:00 The meter just stopped at 3:00 so I'm guessing it would not start again until at least 4:00. That is 7:00 am till 4:00 pm with 1 KWH used for maintenance. My math says 2 2/3 KWH per day for maintanance. or 0.104 x 2 2/3KWH = $0.28 per day. $ 8.40 per month. I'll try checking it overnight. I use a 13 year old 40 gallon Reliance water heater. The heater has 3600 watt elements. Or so the label says. It's in the garage and air temp was about 60* F today.
Mike

"amdx" wrote in message

"amdx" wrote in message
Regarding monitoring the electricity used by the water heater, I purchased a watthour meter on ebay. The cost was $8.00-- plus $13.50 for shipping. Anyway I have had it installed for 24hrs and it reads 23 kwh. My per kwh cost is 10.4 cents, so that is $2.40 cents. I hope this first day is just a high use day. I'll have a better measure in a month or two. Here's a link to one, about $20.00 now. http://cgi.ebay.com/200-AMP-WESTINGHOUSE-WATTHOUR-METER_W0QQitemZ180308738881QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item180308738881&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A15|39%3A1|240%3A1318
It's been two weeks since I put the watthour meter on my water heater. Average daily electricity cost to heat water is $1.77. Family of four, two teens. Mike

I'm now up to 26 days with the electric meter on my water heater. The meter reads 440 Kwhs. 440/26=16.9Kwhs per day @ $0.104 per Kwh that is @ $1.76 per day or $53 per month, or $642 per year. Mike