Why should I be interested in solar hot water?

Won't relying on the sun for my hot water leave me in the cold when its cloudy?

What about the tank-less hot water heater I've had my eye on?

Can I use solar hot water to do radiant floor heating?

How big are the solar hot water panels and where do they go?

What about my friend's funky system from the 1980's that just sits and collects dust?

What makes up a solar hot water panel?

How does a drainback solar hot water system work?

Why do you install Techsun Solar Hot Water Systems rather than brand X?

Why should I be interested in solar hot water?

Because it is significantly more cost effective to reduce your home's energy footprint first. Solar hot water is probably the single biggest step you can take to do this short of buying a more energy efficient or smaller home. This is because heating water can consume up to 25% of a household's total power usage. A solar hot water system will reduce the power consumed heating water by 80% or more. For a household of 3 or more, the payback rate is under 10 years. For commercial applications, the payback period can be much shorter. Solar hot water will make the most sense for residential customers whose solar hot water heater is electric or propane.

Won't relying on the sun for my hot water leave me in the cold when its cloudy?

No. Solar hot water doesn't replace your existing hot water heater. Rather it preheats the water going into it. So if the incoming solar water is not hot enough, then your existing hot water heater will bring it up to the temperature it needs to be. Also, solar hot water tanks are sized larger than regular water tanks. This is so the volume of water is large enough to stay hot overnight. That way when you shower first thing in the morning, solar hot water is what your are mostly consuming.

What about the tank-less hot water heater I've had my eye on?

Tank-less hot water heaters are smart, but some aren't as smart as others. Some manufacturers cut corners and don't add a sensor on the incoming water to see how much it needs to be heated up. If the tank-less hot water heater you're looking can detect the temperature of the incoming water, then it will compliment a solar hot water system quite nicely and result in additional energy savings. Contact the manufacturer of the tank-less hot water heater you are interested in to see if it is compatible with a solar hot water system by asking them- If the incoming water temperature is already hot enough, will the water heater still come on?

Can I use solar hot water to do radiant floor heating?

Yes, but not as a sole means. You can use solar hot water to preheat the water feeding into your radiant flooring boiler. But even a very large solar hot water system will not provide 100% of the hot water necessary to heat a home continuously. Also, the 30% federal tax credit toward solar hot water purchases is limited to $2000 for residential systems. So if you exceed a certain system size you can't get the government to give you the 30% discount on the full amount. Consider this option: If you used the same money to do a small grid tie electric system to offset the power used by an electric boiler, you would be able to get another 30% tax credit back on this system as well (with a cap at a $2000 credit for non-commercial buyers). This is because the tax credit for a solar electric (photo voltaic) system, is a separate one.

Also, if you use a solar hot water panel array to supplement your radiant floor system boiler, you end up having a number of solar hot water panels on your roof not doing anything in the summer when there is the most solar energy to be collected. Whereas a small grid tied PV array would be collecting energy year round.

But on the otherhand, solar thermal systems are more efficient than solar electric and may be worth considering based on the project you are looking at. The best write-up on solar hot water for radiant floor heating I've found can be found here at www.builditsolar.com and was the cover story of the Dec 2007 issue of Home Power.

How big are the solar hot water panels and where do they go?

A typical residential size solar hot water systems might use either one 4’x8’ panel, two 4'x6' panels, or two 4’x8’ panels. Panels should be mounted on the south (ideal) side of a home's roof. If there is not an adequate southern roof exposure, panels can be faced in a different direction then that of the roof's slope by being tilted up on one side. Usually this is simply a matter of putting legs on the back of each panel to tilt them up.

What about my friend's funky system from the 1980's that just sits and collects dust?

Back in the early eighties there was a period of high energy prices which resulted in the first big surge of solar hot water systems installations. As energy prices went back down, people forgot that the natural resources giving us electricity and natural gas were not unlimited (thanks in part inaccurate energy prices from oil and gas subsidies) and resumed using gas and electric systems with renewed fervor. Today environmental consciousness is becoming more widespread, especially regarding the effects of releasing carbon from beneath the earth's surface into the air in a short period of time. As energy prices now begin to rise, solar hot water systems are rapidly being installed with increasing frequency.

So what sets today's solar hot water system apart from those put in 25 years ago? First the panels used are smaller, more efficient, and much more attractive. Next, a majority of the systems installed at that time were what are called closed loop systems which involve using propylene glycol or some other antifreeze solution. Most of the systems installed today are drain back systems, which require no antifreeze. Drain-back systems are more maintenance free, reliable, and efficient than the closed loop systems installed in the past.

What makes up a solar hot water panel?

Solar heating panels consist of a flat rectangular box containing a number of parallel pipes attached to heat absorbing copper fins. These fins are plated with a dark coating designed to absorb as much heat from the sun as possible. The pipes and their fins are enclosed by an anodized aluminum body with an anti-glare glass covering.

How does a drainback solar hot water system work?

In a drain back solar hot water system, there is a volume of about 5 to 8 gallons of water held in the drain back tank. This water is isolated from any water that would come out of your facet and is non-pressurized. When the sun causes the temperature of the panels become hotter than the water in the solar hot water storage tank (and the water in the solar hot water storage tank is not already hot enough), the system controller turns on the system's circulating pumps. The drain back tank pump sends the water in the drain back tank up to the panels to be heated and back to drain back tank. The heat exchange pump comes on and moves water from the solar hot water storage tank through the heat exchanger and retrieves the heat from the water being sent to the panels. The heat exchanger can either be a copper coil contained within the drain back tank itself or an external heat exchange unit. When the water in the solar hot water storage tank is hot enough (or the panel temperature becomes colder than the water in the solar hot water storage tank), the controller turns the pumps off and the water drains out of the panels into the drain back tank. This prevents water from being in the panels that would freeze in the winter or boil in the summer.

Source: http://www.kingsolar.com

Why do you install Techsun Solar Hot Water Systems rather than brand X?

Techsun solar hot water systems are the only SRCC certified systems that allow for easy descaling and desedimentation of the heat exchanger. Having personally performed many solar hot water sytem removals, I can concur with the designer of the Techsun system that the clogging of heat exchangers is probably the primary cause of premature system failure in hard water areas like Oklahoma and Texas. (The second most common source of failure I would attribute to the improper maintenance of glycol based systems: another reason I normally only install drainback). The Techsun system was developed in Austin, TX and is designed to perform under climate and water quality conditions similar to Oklahoma. The Techsun system is designed with only the highest quality of components. Every aspect of the system's design was meticulously planned and engineered with total attention to quality, reliability, and perfection. For more information on the Techsun system, visit Techsun's Website

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