solar hot water

Solar Thermal Is Really, Really Dead

Posted on April 27,2015 by user-756436 in photovoltaic

Back in early 2012, in an article called “Solar Thermal Is Dead,” I announced that “it’s now cheaper to heat water with a photovoltaic array than solar thermal collectors.” Now that almost three years have passed, it’s worth revisiting the topic. In the years since that article was written, the cost to install a photovoltaic (PV) system has dropped significantly. Moreover, I’ve come across monitoring data that allow for a more accurate estimate of the amount of electricity needed to heat water with electric resistance elements or a heat pump.

Solar Hot Water System Maintenance Costs

Posted on April 27,2015 by user-756436 in maintenance

I installed my solar hot water system about six years ago. It’s a good system. I have two 4’x8’ AE-32 flat-plate collectors (manufactured by Alternate Energy Technologies), a Superstor Ultra stainless-steel tank (at 80 gallons, it’s a little small, but it’s what I could afford), and an El Sid DC pump from Ivan Labs. Since I installed the equipment myself, it cost significantly less than a professionally installed system.

Getting Into Hot Water — Part 4

Posted on April 27,2015 by user-1095434 in DHW

I've now had a year with the Geyser heat-pump water heater (HPWH). With the exception of the puddle on the floor in July 2011, it has performed consistently. Its performance has not been thrilling, though. In the summer, it was making hot water at about 0.13 - 0.15 kWh/gallon, with incoming water in the mid-60°Fs and basement air temperature around 70°F. In the winter, with basement temperatures in the low to mid 50°Fs, and incoming water at 50°F or a bit below, this consumption ratio increased to 0.25 kWh/gallon.

Getting into Hot Water — Part 1

Posted on April 27,2015 by user-1095434 in electric resistance

Dick and Tim Mavro, with the help of a large friend of Tim's named Justin, came and took our oil heating system away. I was glad to see the truck drive off with all that equipment on the trailer. Now I have to find a home for the Vermont Castings gas heater, and then we'll be fossil-fuel-free, at least as far as site energy is concerned.

Solar Thermal is Dead

Posted on April 27,2015 by user-756436 in domestic hot water

In the northern half of the U.S. — and even much of the South — installing a residential solar hot water system doesn’t make any sense. It’s time to rethink traditional advice about installing a solar hot water system, because it’s now cheaper to heat water with a photovoltaic (PV) array than solar thermal collectors. In short, unless you’re building a laundromat or college dorm, solar thermal is dead.

German Innovation in Solar Water Heating

Posted on April 27,2015 by AlexWilson in domestic hot water

I was in Boston last week for the annual Building Energy conference, sponsored by the Northeast Sustainable Energy Association. Each year this conference provides an opportunity to connect with friends and colleagues, catch up on leading-edge building design, and learn about product innovations in energy conservation and renewable energy.

Passive House in the Woods Goes Energy-Positive

Posted on April 27,2015 by Fretboard in Hudson

As the clock wound down on 2011, marking a full year of monitoring for Passive House in the Woods, in frosty Hudson, Wisconsin, it became clear that the building’s design, construction, and renewable-energy systems had combined to deliver net-zero-energy performance, and then some.

Teaching Deep Green by Building It

Posted on April 27,2015 by Fretboard in Construction Education

The project is being called Canada’s Greenest Home, which sets the bar pretty high, but the Endeavour Centre, a nonprofit building school in Peterborough, Ontario, decided the time is right. Endeavour encourages its students to engage their minds and “get their hands dirty” on ambitious projects, including this 2,000-sq.-ft. two-story home, which is designed for an infill lot in Peterborough and will be the focus of the school’s five-month Sustainable New Construction certificate program.

All About Water Heaters

Posted on April 27,2015 by user-756436 in heat-pump water heater

If you want to save energy, there are lots of exciting appliances and building materials that you might want to specify for your home: triple-glazed windows, an efficient refrigerator, and compact fluorescent or LED lighting, for example. When it comes to choosing a water heater, though, clarity evaporates. Simple, affordable water heaters aren’t very efficient, and efficient equipment is complicated and costly. So how do you go about choosing a water heater?

Solar Decathlon 2011: Tidewater Virginia

Posted on April 27,2015 by Fretboard in Hampton University

Team Tidewater Virginia set out to build a house that will work exceptionally well as a stand-alone home. The modular house is also designed to work as one of six units in a multifamily project being designed for the Park Place neighborhood of downtown Norfolk, Virginia.

Solar Decathlon 2011: Team China’s Y Container

Posted on April 27,2015 by Fretboard in China

Team China’s Solar Decathlon 2011 entry, Y Container, pushes hard on the notion that shipping containers can be as comfortable to live in as they are easy to transport from mainland China to Washington, D.C.

Energy and Construction Photos from Greece

Posted on April 27,2015 by user-756436 in Athens

You can put away your building science notebooks; this blog is simply a collection of photos from my recent vacation in Greece. While the purpose of my trip was relaxation, I still managed to point my camera at a few construction sites and examples of renewable-energy equipment.

7 Steps to an Energy-Efficient House: 5. Mechanicals

Posted on April 27,2015 by Betsy Pettit in air conditioner

Editor's introduction: With energy prices rising again, many homeowners are planning energy-efficiency improvements to their homes. But most people are unsure of where to begin, and even seasoned builders don’t always know which priorities should rise to the top of the list. Betsy Pettit, an architect at [Building Science Corporation](, recommends starting where you can get the most bang for the buck. Step 5: Replace your furnace, boiler, or water heater

Closing in on HOA Solar-Installation Restrictions

Posted on April 27,2015 by Fretboard in community restrictions

One of the sideshows in the relatively slow growth of renewable energy in the U.S. has been the conflict between homeowners associations and property owners when the latter want to install solar power.

Deciphering the Tax Credits

Posted on April 27,2015 by user-756436 in energy efficiency

The energy-efficiency tax credits and renewable-energy tax credits are better than tax deductions. The allowable credits aren’t just deductible expenses; they represent dollars subtracted directly from your tax bill. While the tax credit program includes illogical rules, the available tax credits can be significant. If you want to claim a tax credit on your 2009 income tax return for energy-efficiency improvements to your home, you should get the improvements installed before the end of the year. There’s really no need to rush, however, since the tax credits will remain available until the end of 2010 — or, in some cases, 2016.

Solar Hot Water

Posted on April 27,2015 by user-756436 in domestic hot water

If you’re aiming to reduce your carbon footprint, you’ve probably thought about installing a solar hot water system. Here’s the good news: if you have an unshaded south-facing roof, you can install a solar hot water system that will meet about half your annual hot water needs. The bad news: the typical solar hot water system costs between $6,000 and $10,000.

Florida Utility Warms Up Its Solar Hot Water Program

Posted on April 27,2015 by Fretboard in Florida

Though significantly more expensive than conventional hot water heaters to buy and install, solar hot water systems can efficiently meet as much as half the hot water needs of households in many parts of the country. And the systems' cost-effectiveness is highest, not surprisingly, in warm-weather climates.

Passive Hot Air from Everyday Materials

Posted on April 27,2015 by Mike_Maines in Heat recovery ventilators

At the Unity, Maine, headquarters of the Maine Organic Farmers and Gardeners Association (MOFGA), engineer Jay LeGore has harnessed the power of the sun to replace about 200 gallons of propane a year.

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