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Solor Hot Water for my home. An exploration in feasibility and affordability.

24 March 2009

If anyone is inclined to read this, I will post my path to solar hot water for my home. It appears to be the most affordable way to get in the renewable energy game.

I'll post here on my updates through this journey. So far here's what I have to start:

- Significant space on south facing roof.

- Hot water tank is 50 gal, natural gas heated.

- Four people in my home that use water for showers, baths, etc.

- Two rooms in my home that are cold all winter due to north facing location and poorly installed ductwork. Made improvements to ductwork including sealing and inline fan. Still need supplemental heat - currently use electric space heaters (ugh!)

I'm in the process of contacting contractors for an estimate. I'll keep you posted...

24 March 2009

Headed to an energy seminar put on by one of the local solar hot water contractors. They do geothermal, PV solar and solar hot water. Hope to learn more and will share.

30 March 2009

Attending a local seminar on solar thermal including hot water and heated air. Very simple yet effective options for both. I expect to have an appointment in April to estimate solar panels for hot water. I'll share my ROI numbers. This company is not far from my home and manufacture their own panels (www.mes1.com).

07 April 2009

On spring break vacation with my family. Expecting to arrive home to a few quotes. Had two seperate companies visit and assess my options. They both were very different in terms of their experience but appeared very capable.

19 April 2009

Recieved my first bid last week. Included 3 4'x8' panels, storage tank, heat exchanger and radiant flooring in two rooms. I really need to explore whether radiant flooring will work efficiently with solar hot water. Especially in the winter.

24 April 2009

The last bid I received included radiant flooring. A new bid was just for domestic hot water. Basically $13k for solar hot water with radiant flooring (in two small rooms). For solar hot water only, it's about $8-9K. After figuring out by hot water usage/cost, it's about 11 year ROI. I was hoping for about 7-8 years. Hmm.

24 May 2009

Well it's been a month since my last update. I have little progress. Only one of the two contractors that looked at my house for solar hot water actually provided me with a quote. That was the 7+ year ROI. That was with every possible incentive, rebate, etc. built into the equation plus anticipated increase in natural gas and electricity costs. So now what? I'm not sure really. I'm going to explore retorfitting foam insulation into the walls of my home to keep it comfortable and lower my heating/cooling costs. I may looking into solar PV panels again too. Hey, I'd love to hear from someone that has tried there own experiment with green technology. I'll post when I have more news to share...

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Comments Login to leave comment

Vote: +1

"Have look at ground thermal heating for space heating rather than solar thermal, which is better just for water heating I think- depends on where you live of course"

By: Natural Choices :: 2 years ago

Vote: +1

"I have explored ground thermal heating. GeoThermal in our area would run about $30,000. I have an energy star furnace that's only about 9 years old. There are cost savings by going Geothermal but it would take about 15-20 years for any payback. I think in that time there will be more innovative solutions. Instead I have been insulating the heck out of our home to retain every penny spent on heat that is possible."

By: Craig :: 2 years ago

Vote: +1

"We're also considering -- see our post on this at ThinHouse ( http://thinhouse.net/?p=428 0 and the comments. Good luck and keep us posted! Tom"

By: Tom :: 2 years ago

Vote: +1

"Definitely Craig. Keep us posted. we want to follow your journey."

By: Hess :: 2 years ago

Vote: +1

"Hi Craig,
What part of the world do you live in and what kind of kWh and Therm usage do you have?
I may be able to help you find a cost effective way to get as energy independent as possible without selling all your blood for the next 30 years."

By: Solar-Guy :: 2 years ago

Vote: +1

"Updated my blog for anyone interested in my numbers."

By: Craig :: 2 years ago

Vote: +1

"I've installed radiant floor heaters. You need a tremendous amount of storge space, and even then the benifit is minimal in the winter when you need it.

Much more cost effective to put in a flash tankless electric water heater. The whole house model is about $825. Then put up PV panels which produce electricity anytime you have sunlight. Thermal systems need hot sun, which isn't available in the winter.

For your space heating, you could add baseboard electric heaters at a low cost. Use your PV system to generate the electricity to run them.

Any questions on PV, I'll be happy to help. Your payback should be"

By: Solar-Guy :: 2 years ago

Vote: +1

"...less than 8 years"

By: Solar-Guy :: 2 years ago

Vote: +1

"By the way, the three 4X8 panels for solar thermal is just enough to do your DHW; up to 80 gal, with nothing left for heating the rooms. To heat 400 square ft. of living space you need 300 gal of storage, with 10 4X8 panels to heat the tank. It will not work otherwise; you'll still have to supplement it with gas anyway.
Don't do it; it's not the way to go!"

By: Solar-Guy :: 2 years ago

Vote: +1

"Here's the link for that whole-house tankless water heater. You'll have instant hot water, at a fraction of the cost. If you don't go solar PV, use the gas version, it's 10% of the energy you're using on your traditional water heater. I found one for about $650.
http://www.discounttankless.net/store/EEMAX01.html
Good Luck!"

By: Solar-Guy :: 2 years ago

Vote: +1

"Thanks for your comments Solar Guy. I too am concerned about the radiant flooring and solar hot water for some of the same reasons you mention. When you need it most (winter) is when you have the least amount of sun. The storage tanks are pretty efficient but would need to keep the water hot for more than 18 hours assuming the peak sun is at 2pm in winter and needed first thing the next morning to warm up the bathroom. The system I am looking at would pre-heat the water in our existing natural gas based hot water tank. I would need more panels and larger storage all for about 3 or so months of the year. I still want radiant flooring but need to find a better solution. What PV panels do you recommend?"

By: Craig :: 2 years ago

Vote: +1

"A 3.88 kW DC system using Sharp 216U and a SMA inverter will produce the following...
(I used .25 per kWh as that's about average) I picked a zip code in Ann Arbor and this is with a south facing roof.

"Station Identification"
"Cell ID:","0249366"
"State:","Michigan"
"Lat (deg N):", 42.42
"Long (deg W):", -83.02
"PV System Specifications"
"DC Rating:"," 3.9 kW"
"DC to AC Derate Factor:"," 0.790"
"AC Rating:"," 3.1 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 42.5"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:","25.0 cents/kWh"

Chart
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 2.71, 271, 67.75
2, 3.61, 321, 80.25
3, 4.43, 423, 105.75
4, 5.14, 457, 114.25
5, 5.50, 486, 121.50
6, 5.71, 475, 118.75
7, 5.60, 471, 117.75
8, 5.36, 462, 115.50
9, 5.05, 429, 107.25
10, 3.85, 351, 87.75
11, 2.46, 217, 54.25
12, 1.99, 192, 48.00
"Year", 4.29, 4556, 1139.00

If you have less room, Sanyo 205 would be a better choice. They are more expensive per watt, put have more output per sq. foot.

Let me know if that makes any sense. The chart would copy to the blog.
My best!"

By: Solar-Guy :: 2 years ago

Vote: +1

"It will be dark out when we need it most (early morning winter). We'll need batteries if we go the PV route."

By: Craig :: 2 years ago

Vote: +1

"No, you tie the pv system to the grid. You run the meter backwards when you have sunlight and use the power just like you do now when you don't. It doesn't change your lifestyle at all, you just have no or little electric bills."

By: Solar-Guy :: 2 years ago

Vote: +1

"Thanks Solar Guy. That's an option."

By: Craig :: 2 years ago

Vote: +1

"Very cool, Craig. I look forward to further updates."

By: Penelope51 :: 2 years ago

Vote: +0

"Have you considered a solar heater?

This basically simply reflects sunlight into a black box full of water, collecting a surprising amount of heat for free. If the black box has an additional water pipe running through it, any water flowing through this pipe will pick up heat from the hot water surrounding the pipe.

Convection alone should be sufficient to send it to an insulated storage tank (in the roof, for example). This is much simpler and cheaper than probably any other method.

Try putting 'solar heater Youtube' into a search engine - there are many illustrations out there. Also look at 'solar oven YouTube' - same idea, different application.

You can at least see the principle at work then, and adapt it to your own situation."

By: Brian Balloo :: 2 years ago

Vote: +0

"I've been inspired by this to try and get my parents to look into solar heating. If I find anything of note, I promise I'll let you know."

By: taffygirl :: 1 year ago