The process of converting a house to renewable energy begins with:
1. Upgrading its passive solar features, then,
2. Tightening the envelope through adding insulation, upgrading windows, and so forth.
3. The next stage is adding solar hot water heating. Heating water accounts for a quarter to a third of energy usage in a home and using solar water heating can substantially cut the energy bill.
4. Then PV.
5. And then whatever is still needed.
Let's look at three options for adding solar water heating to our homes.

We're now starting to look into solar hot water - hopefully to install before this coming winter, finances depending. (Yes, winter is coming :=) Here's what I've learned so far.

1. Older Tube Solar Hot Water Technology

Here is a good explanation of the older process http://www.solarhotwaterheaters.org

There are 2 types of solar heat collectors - Flat plate solar collectors and evacuated tube solar collectors.
Evacuated tubes are glass tubes with a vacuum inside them and copper pipes are in the center.
Heat is drawn from the dark glass and absorbed into the copper pipes which share a manifold where a circulating pump moves the heated water into a insulated storage tank. This storage tank allows the water to be used that night or the next day.

Flat plate collectors work using copper lines running in a glass covered collector which sometimes has a external storage tank right on the unit. The hot water can then be drawn right from the tank.

Evacuated tube collector based systems are the better choice:

• Captures more sunlight as they have a greater surface area exposed to the sun
• Are more efficient in the transferring heat
• Can be used in freezing temperatures
• If a tube breaks, it can be replaced
• Excellent operation in overcast conditions on cloudy days
• Require a smaller roof footprint compared to flat plate collectors
• Low level of corrosion problems compared to flat plate collectors

http://www.solarhotwaterheaters.org

2. New PV Hot Water Systems

Martin Holladay is senior editor at Green Building Advisor, a site filled with tasty goodies.
http://www.greenbuildingadvisor.com/team/martin-holladay-gba-advisor
He concluded in the late 200s that the drop in PV costs and the relative simplicity and less maintenance makes solar thermal obsolete. He revisited it in 2014 and found that the case ws then overwhelming for PV solar heating systems.

Comparing three systems

My latest approach to comparing the cost of solar equipment used to make domestic hot water starts with the assumption that the typical solar fraction of a cold-climate solar thermal system is 63%.
Keeping that solar fraction in mind, I have calculated the cost of equipment for three scenarios:
House A has a solar thermal system (two rooftop collectors and a solar storage tank in the 80 to 120 gallon range) and an electric-resistance water heater for backup.
House B has an electric-resistance water heater and a PV system sized to provide enough electricity on an annual basis to meet 63% of the family’s hot water needs.
House C has a heat-pump water heater and a PV system sized to provide enough electricity on an annual basis to meet 63% of the family’s hot water needs.
The table below compares three homes in Boston, each of which uses 44 gallons of domestic hot water per day.

According to this analysis, the PV plus electric-resistance approach is about 25% cheaper than the solar thermal route, and the PV plus heat-pump approach is about 50% cheaper than the solar thermal route.

Everyone's numbers are going to be different
What if you are a solar thermal buff who thinks that my assumptions are unfair to solar thermal? Well, let’s change a few numbers. We’ll assume that a solar thermal system costs only $6,000 to install and that the solar fraction is 75%.

I think that the assumptions made in the above table are unrealistic, since it's hard to find a contractor willing to install a good two-collector solar thermal system for $6,000, and because in a location with a solar fraction of 75% a PV system is likely to produce more electricity than this table shows. But according to this analysis, the PV plus heat-pump approach is still about 23% cheaper than the solar thermal route.

http://www.greenbuildingadvisor.com/blogs/dept/musings/solar-thermal-rea...

3. Geothermal

Then there's the enticing option of geothermal, where technology has also vastly improved.
Today's geothermal uses 3' copper tubing instead of the old space-eating gigantic plastic loops.
Which means the heating and cooling system can also heat water.
I'm looking at an installer in Ottawa, http://www.geothermalexperts.ca/products_earthlinked_heating.php.php.
They are a dealer for the products of a U.S. company called Earthlink Technologies http://earthlinked.com/products/

Here's the three earth loop options available:

http://www.geothermalexperts.ca/pdf/DXEarthLoops-Options.pdf

Here's their marketing spiel:

http://www.geothermalexperts.ca/pdf/EarthLinkedSHC-factsheet.pdf

Solar Energy from the Shallow Earth
Reduced fossil fuel consumption, reduced emissions and increased comfort result from the use of renewable solar energy stored in the shallow earth. These benefits are delivered by the EarthLinked® heat pump system.

Almost half of the sun’s energy that reaches the earth is stored in the ground, resulting in a solar battery that can be used for heating anytime, anywhere that people live. The constant and favorable temperature of the earth also makes it a favorable heat sink to receive unwanted heat in the cooling season.

The EarthLinked system is a heat pump that uses the refrigeration cycle to move heat from one location to another, like an air conditioner that can also operate in reverse. It’s a unique heat pump because the patented refrigerant flow controls enable it to directly connect with small earth loop tubes that can be installed vertically, diagonally or horizontally in 3” bore holes 50 to 100 feet (15 to 30 m) in length. Typically, the earth loops are 100 feet per ton (12,000 BTU) of capacity.

The diagonal loop configuration exchanges heat in a large subsurface area but impacts a small six foot diameter area at the surface during installation. The system, the earth loops and the boring equipment are small, so the installed footprint is small and the system is very adaptable for retrofit installations.

Because of its efficient use of the favorable earth temperature as a heat source/heat sink and its direct heat exchange method, the EarthLinked system is more efficient than an air source heat pump (ASHP) and other geothermal heat pump (GHP) units that must circulate water for heat exchange.

One System, Multiple Uses
Whether you live in Australia or Alaska, the EarthLinked system is the simple solution to a comfortable environment throughout your home. A single unit can provide space heating and cooling, and water heating, no matter the climate conditions. Because of its small size and mechanical simplicity the system is convenient, reliable and easy to maintain.

Space Heating and Cooling
Thousands of property owners in North America and around the world use EarthLinked to heat or cool buildings. The system delivers a stable, comfortable temperature all year round. In summer there is a greater dehumidification because of colder refrigerant coils and longer run cycles. In winter there are no blasts of hot air as with a furnace, and the heated air is warmer than with an air source heat pump because the earth is a warmer heat source. For maximum winter comfort and efficiency, the EarthLinked system can also be coupled with a radiant hydronic system.

Water Heating Option
You can use the EarthLinked system to heat water up to 125°F (52°C), optimizing your energy consumption and saving money. The system uses waste heat given off in the air‐conditioning mode in summer or natural heat stored in the ground and harvested by the heating mode in winter. Either way, you can reduce your water‐ heating costs by as much as 75% compared to electric resistance heating.

Swimming Pool Heating
No matter the size of your pool, the EarthLinked system can quietly heat the water to a comfortable temperature without harmful combustion byproducts— all with the highest efficiency.

http://www.geothermalexperts.ca/pdf/EarthLinkedSHC-factsheet.pdf

So those appear to be the three options for solar thermal:

• Older Tube technology, as a stand-alone system
• New lower-cost PV, in combination with a house solar electricity system
• Geothermal, in combination with air heating and cooling

We're not ready for a full PV system. Plus, there are no more green subsidies in Canada, except possibly in geothermal. Perhaps, maybe...
I think though, I'm going to ask for a quote for the geothermal option.

I'd appreciate any feedback and guidance from your experience possible.
Peace be with us, if we work to make ourselves energy-independent,
gerrit