Tankless on demand (propane, cheaper, bank)

[terracore]

"And if they can't handle an electric bill - they should - move."


Good plan. We'll send them to your island.

[Amadrid]

Originally Posted by Pyramidsurf

Are you talking solar PV system or solar hot water heater? There is no way a solar water heater cost 11K.

The house I purchased has a solar hot water heater system and its great. I actually don't even need to turn on my hot water heater unless there is multiple days of overcast. I leave the system off and let the tank hold the hot water. I can't see why anyone would want to go with a tankless system in Hawaii. My electric bill on Oahu is down to about $120 per month.

I’m guessing that the quote was for a PV system. If I was going to go solar, that’s what I would do, not just solar water heater. My current water heater is propane. In the winter our electric bill gets high because of space heaters. We have an HVAC system that was in the house and installed by the previous owners but when we purchased the property, the system did not function. I suspect running it will really push the electricity bills

[hotzcatz]

I kinda looked at solar water a couple years ago and got a rough estimate of $5K. That was an off the cuff answer, the number could be lower.


HOWEVER, since your current water heater is propane, it's not the one making the electric bills high.


If that $11K is for a PV system big enough to run the house, that's really good price, IMHO. We paid twice that plus another quarter for the first big PV install and then twice that again for the big PV on the next house. It's really nice having $20 electric bills, though.

[Frankjake]

I’m a CA licensed plumbing contractor and have been for nearly 30 years. Regarding tankless or “on demand” water heaters, to this day I honestly can’t answer if they are any better or cheaper than a standard tank type water heater. Everybody has different needs. So it kind of translates into the right tool for the right situation.

I don’t know what most people consider a “normal” electric bill or propane bill. We have now been in our Ocean View home for two full months. Both of us are here everyday and all day long except for the occasional trip to Kona or Hilo. Retirement is great!

For us, all we have to compare electricity and gas (propane) is what we were paying in Southern California in a beach community north of Los Angeles. In CA we had natural gas for cooking, heat, hot water and clothes dryer. Electricity was basically lighting and the fan for the furnace. Gas and electric combined would average $150 to $160 a month. We both worked and were gone 10 hours a day. We were out most of the day on Saturday and home all day Sunday. No heat or A/C left running when not at home.

The past 2 months in Ocean View we’ve both been home 6 days a week, all day. Our Hawaii house is 400 sf larger, (2,000sf). We have propane cooking and tank style water heater. Dryer is electric and any heat comes from portable electric heaters. Propane via two 30lb tanks (about 7.5 gallons each) & two 20lb tanks cost us $70 each month roughly. That’s probably $4 or $5 on the high side. Electricity bill has averaged $150 a month for the last two months. Combines that’s about $210 to $220 per month.

So it seems our gas and electricity is costing us about $70 a month more than it was costing us in CA. The price per kilowatt here is double of what we were charged in CA. Gas, well I don’t want to take time to figure out gallons and cubic feet.

I don’t know how long it would take to pay for itself by buying any type of solar. Most people I’ve talked to can’t really give me a real figure as far as savings. Then they forget to include any unforeseen issues such as roof repair/replacement or repairs to the solar system itself. While the idea of free hot water and free electricity sound great, how long would it truly take to get to that point!

Even spending $5,000 for a solar hot water system at a savings of propane of $50 a month (guessing), it would take 100 months just to break even. Would that system last 8 years? How many people stay in that same house for 8 years? What system repairs would be needed in that 8 years? There are so many variables to consider. I don’t think there’s one answer for everyone. Just my two cents worth. Thanks for reading and please forgive any typos.

[whtviper1]

Originally Posted by Frankjake

I don’t know how long it would take to pay for itself by buying any type of solar. Most people I’ve talked to can’t really give me a real figure as far as savings. Then they forget to include any unforeseen issues such as roof repair/replacement or repairs to the solar system itself. While the idea of free hot water and free electricity sound great, how long would it truly take to get to that point!

Even spending $5,000 for a solar hot water system at a savings of propane of $50 a month (guessing), it would take 100 months just to break even. Would that system last 8 years? How many people stay in that same house for 8 years? What system repairs would be needed in that 8 years? There are so many variables to consider. I don’t think there’s one answer for everyone. Just my two cents worth. Thanks for reading and please forgive any typos.

But you aren't going to pay $5,000 - you've got a 30% Fed tax credit - a 35% cost credit from Hawaii - a $750 Hawaii instant credit - and it should certainly last more than 8 years and potentially increase the value of your home.

[hotzcatz]

Usually the big financial savings on solar hot water is when the water heater is electric, but ecologically, heating things with solar is much better than fossil fuels.


Solar hot water doesn't have any moving parts other than the pump and that's usually a small quarter horse pump or even smaller. PV doesn't have any moving parts either. Either system should last for decades without much maintenance.



I've still got functional solar PV panels from 1984 that are still working fine. Stand alone PV systems need batteries, which need replacing every 7-10 years (now that there's charge controllers for the battery banks). If you have a grid tie system, you don't need the battery banks.


By not having the electric or propane bills, it makes month-to-month expenses much lower. Then you can chunk money at various other cost savings options.


Given a choice between a solar water heating system and an on demand water heater, I'd opt for the solar - absolutely. Much better experience with the hot water usage as well as less cost of running the system.

[Frankjake]

Thank you both for that good information. There must be a need for some better salespeople. The few professionals we’ve talked with don’t make the discounts sound nearly as good as whtviper1. Nor do they sell the customer on the longevity of the system. Decisions Decisions ��

[terracore]

"Even spending $5,000 for a solar hot water system at a savings of propane of $50 a month (guessing), it would take 100 months just to break even."


After rebates, credits, tax situations, etc our "our of pocket" price was WELL under 2k. I remember at the time thinking the repayment period was about 3-4 years. 7 years later we're enjoying our "free" hot water.

[Pyramidsurf]

I'm not sure on costs but I do know my solar hot water heater saves 50 to 60 dollars a month in electricity. I didn't pay for the system but it seems to work well. Like I said earlier, I keep my water heater off 95% of the time and have more than enough hot water.

[MickeyE]

Uuummmm - remember this?: https://metaefficient.com/news/solar...in-hawaii.html and I quote:

Solar Water Heaters Now Mandatory In Hawaii

June 29, 2008

Hawaii has become the first state to require solar water heaters in new homes. The bill was signed into law by Governor Linda Lingle, a Republican. It requires the energy-saving systems in homes starting in 2010. It prohibits issuing building permits for single-family homes that do not have solar water heaters.

Some interesting info on variances are at Hawaii State Energy Office | Solar Water Heater Variance .

Y'all might want to look at Hawaii State Energy Office too. Some interesting and ambitious things going on there.


Mickey