I recently noted that Hawaii has enacted a law that requires all new homes to install solar water heaters. Eventually, Hawaii may have as many water heaters as Israel, where 90% of homes have solar water heaters installed. When viewed from above, the Jerusalem often glitters with the shine of the thousands of solar heaters that adorn rooftops. (more…)

The Proximity Hotel is proof that a hotel can be very green without sacrificing the comfort of its guests. The hotel is located in Greensboro, North Carolina, and it achieved a Gold LEED certification this year from the U.S. Green Building Council. The Proximity uses 36.5% less energy and 30% less water than a conventional hotel. It gets 60% of its hot water from 100 solar thermal panels on the roof. The hotel also boasts the first regenerative drive elevator, which recaptures energy as the elevator moves down.

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Solar Water Heating is the first book I’ve seen that focuses solely on solar water heating. It’s a technique that’s been practiced since ancient times, but until now there’s been strangely few resources on the topic for a North American audience. The author, Bob Ramlow, examines state-of-the-art solar heating systems. He covers not only solar water heaters, but also solar water and space house heating systems and solar pool heating systems, including their advantages and disadvantages. Since people often get turned off by the up-front cost, the book focuses especially on the financial aspects of solar water or space heating systems, and shows that such systems can save significant costs in the long run.

It’s available from Amazon for $16.47.

A Canadian company, Pulsar Advanced Technologies, claims to have produced a water heater that uses microwave technology to heat water instantaneously. The company says: “The Vulcanus MK4 can heat water from 35 degrees Fahrenheit to 140 degrees Fahrenheit in seconds and can source multiple applications at once: showers, dishwasher, sink usages and more. The Vulcanus MK4 is the size of a stereo speaker with a sleek modern look, making it ideal for condos and apartments, while powerful enough to serve the needs of any size family.” Groovy Green has been tracking the progress of this product, and the latest update can be found here. Apparently the heater isn’t quite to market yet, the manufacturers are looking to be certified in the U.S. and Canada.

Takagi water heaters do not have tanks, instead they heat water instanteously using a gas burner. They are efficient and powerful — even the smallest heater, the Takagi T-KJr., can produces 180 gallons of hot water in an hour, but weighs only 30 pounds and is 20 inches high. They run on propane or natural gas.

Computer controlled electronic ignition allows the heater to operate without a pilot light and save up to 50% off utility costs. Prices range from $600-$1000. The heaters also have powered ventilation, computer-modulated gas flame for steady output temperatures and the industry’s best energy factor of 0.84

Takagi heaters can be used with solar preheated incoming water — only adding additional heat as needed to meet a set output temperature.

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Solar water heating works efficiently even in cloudy areas. Home Power Magazine recently ran an article that gives a simple overview of solar water heating systems (well, relatively simple).

In the article, they examine various popular systems that have proven themselves reliable.

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Apricus makes a unique solar hot water heater which is 30-40% more efficient than flat plate solar systems.

The secret to the performance is the use of cylindrical evacuated glass tubes to absorb the heat from the sun. Because the tubes are cylindrical, there is always a surface area that is perpendicular to the sun.

The tubes also house a vacuum between two layers of glass. Why a vacuum? A vacuum is an excellent insulator. The insulation properties are so good that while the inside of the tube may be 304°F (150°C), the outer tube is cold to touch. This means that solar tube water heaters can perform well even in cold weather when flat plate collectors perform poorly due to heat loss.

More information: Apricus

Aquastar tankless water heaters cut energy costs, because the heat the water as it is needed. These heaters are designed
so that all parts are replaceable.

Alexander Rose, who has used and reviewed this heaters says:

There is a whole Aquastar line from large ones for multi shower households, to the smaller ones like mine. Some are made to work in line with solar radiant heating, some with propane, some with natural gas. I really like the HX model because it works with no outside power source or pilot for ignition, making it very efficient, safe and reliable. They cost more than standard water heaters (mine was $550) but they pay for themselves fast in power bills since you don’t have to keep a large tank of water heated all the time; you only make hot water exactly when you need it.

Aquastar heaters can be bought with a hydro-generated ignition system that requires no pilot, batteries or electricity and saves energy over a standing pilot system.

Except for the ignition system, the 125HX(hydro-ignition) is the same as the 125B(standing pilot).

These heater have a 2
year warranty with 10 year warranty on heat exchanger.

Purchase from: TanklessWater.Com ($564)

Here is a review of this heater.

Notes from Manufacturer:
The AquaStar 240FX (Natural Gas or Propane)
can supply 2 major hot water outlets at the same time at a rate of up to
5 gallons per minute. Can be vented vertically or horizontally to the outside.

High efficiency rating of 83% and an
Energy Factor of .84.

Purchase from: TanklessWater.Com

Designed and made in Italy, Ariston hot water heaters have a lot going for them. They plug in directly under the sink or wherever you want hot water. They produce hot water instantly — you don’t have to wait for the water to get hot (80 billion gallons of water is wasted annually in the U.S. this way).

The hot water doesn’t lose heat as it travels through pipes from a distant heater. The tanks are well insulated with glass so there is not much heat loss. They draw 12.5 amps. They range in price from $139 to $169. Warrantied for 6 years.

Ariston Heaters are now sold by Bosch. Ariston Heaters are available from Amazon.