Green Building Elements

Author’s note: the following article on home heating is the final one in an eight-part series. If you are thinking about installing a wood-burning mass heater, this article should help you.

Operating a Mass Heater
Mass heaters are a different approach to burning wood. If you don’t don’t understand this, you won’t just be disappointed — you’ll fill your house with smoke or, worse, poison your family in their sleep! Getting proper performance from a mass heater requires a little planning, and some involvement, on your part.  The tradeoff for this extra effort is safety and tremendous energy efficiency.

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Author’s note: the following article on home heating is the seventh in an eight-part series. If adding thermal mass to your house isn’t realistic, another approach is to install a massive heater. That is to say, the heater contains the thermal mass your house may lack.

Clean and Super-Efficient Wood Heating
Super-efficient wood burning heaters with lots of mass are called by many names: masonry stoves, russian stoves, finnish stoves or finnish fireplaces, mass heaters. Though mass heaters may look like traditional fireplaces, they’re actually very sophisticated heating devices.

Burning wood in a mass heater doesn’t involve feeding in wood a few pieces at a time. The wood is added all at once, lit, and burned as quickly and as hotly as possible. Because of the high combustion temperature, there’s virtually no smoke. Combustion is so complete that, with the exception of a bit of smoke released when the fire is first started, most of what comes out of the chimney is carbon dioxide and water vapor. Read the rest of this entry »

Author’s note: the following article on home heating is the sixth in an eight-part series.

Metal woodstoves are a significant improvement over open fireplaces from the standpoint of producing more usable heat. They limit incoming air, thus avoiding heating air not needed for combustion. Another improvement: they use a lengthened heat exchange pathway to improve heat transfer from the heated combustion gases before they exit the chimney.

Unfortunately, metal woodstoves must operate at low, inefficient, and polluting combustion temperatures. Why? Because wood combustion requires high temperatures to be clean and efficient. Wood burns starts to burn cleanly at around 1200 degrees Fahrenheit, with continuous improvement up to about 2000 degrees. Cast iron begins to glow red and fail at about 1200 degrees. See the problem?

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I don’t know how you spent your weekend, but we spent ours with hands outstretched, feeling for hot, attic air shooting out of electrical outlets, ventilation fans and air vents. After months of crazy-high electric bills, we decided to get to the bottom of why it was costing so darn much to cool our rather small home.

Enter the HERS Rater (Home Energy Rating System).

It turns out there are wonderful people who will come to your home, put up a strange looking contraption called a “blower door” on either your front door or entry to the attached garage. A fan is turned on, the pressure is measured (our house was brought to -50 Pascals) and the cubic feet per minute of air that is rushing out of the house is measured.

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As part of their year-long “Change the World, Start with ENERGY STAR” campaign, EPA has launched a website to help you save money and and energy with your programmable thermostat. A programmable thermostat properly programmed and used can reduce 1,847 lbs of green house gas emissions a year. According to the EPA, maximizing household energy use through serviced heating and cooling systems, leak-less ducts, and thermostats that are programmed to save energy at night or when residents are away, would prevent 169 billion lbs of greenhouse gas emissions per year. To those who are more swayed by the impact on their wallets, programmable thermostats can save about $180 a year. Find valuable tips and resources, including tutorials and a video podcast, on their new website www.energystar.gov/programmablethermostats.

Some of the helpful tips include lowering the temperature setting by 8 degrees when you’re away or asleep in the winter, or raising the temperature setting by 7 degrees when you’re away and 4 degrees when you’re asleep in the winter. Take advantage of the “Vacation” and “Hold” features to manage temperatures while you’re away from home for an extended period. More helpful tips from the EPA: Read the rest of this entry »

Author’s note: the following article on home heating is the fifth in an eight-part series.

Open fireplaces have a reputation for polluting air. Actually, a fireplace, when burned hot and fast, creates very little pollution. The trouble is, a hot fire in a fireplace sometimes yields less heat than a smoldering fire. Where does the heat go?

The optimal amount of combustion air contains just enough oxygen to burn all combustible gases liberated by the heat. Any additional air grabs heat and sends it up the chimney. Under some circumstances, fireplaces can so far exceed this air-to-fuel ratio that they suck more heat out of a house than they radiate back into it. The fire actually makes the house colder!

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Author’s note: the following article on home heating is the fourth in an eight-part series.

The previous article discussed the disadvantages of using forced air to heat your house. Another approach is, literally, to heat your house –- not the air cycling through it. Why would you want to do this?

Well, for one, when you heat the building itself, you can open all the doors and windows, let all the warm air escape, close everything back up, and, instantly, be warm again – without having to add more heat.

The Empty Fridge

Warm masses heat you like the sun does: by sending you radiant heat. As I explained in Heating Your Home: Heat 101, heating and cooling differ only in perspective. If you can get your head around that, then the Empty Refrigerator Effect explains why heating air is an inefficient way to heat a home.

Like it says in the fine print, refrigerators achieve their rated efficiencies only when they’re full. Every time you open the door, warm air enters. If the fridge is empty, the inside temperature may go up five or ten degrees. Read the rest of this entry »

Editor’s note: While we’ve discussed home geothermal systems a number of times around the Green Options Media network (see the list at the bottom), we’re glad to bring you today’s post from GreenBuildingTalk on the subject. They not only provide an overview of the technology, but point you to some cutting-edge models of geothermal heat pumps. This post was originally published on Thursday, May 15, 2008.

With energy costs on the rise, homeowners are looking for ways to offset higher bills. Geothermal heat pumps are one of the best options, as they currently offer the highest efficiencies of any heating and cooling system available today. A study by MIT emphasizes the potential for geothermal, and manufacturers are offering more options for consumers. While at the Midwest Builders show, I stopped by ClimateMaster and WaterFurnace booths to learn more about their newest offerings. Before diving into the respective systems, let’s review the three main components of a geothermal system; the heat-pump unit, the liquid heat-exchange medium (open or closed loop), and the air-delivery system (ductwork).

The heat pump simply moves heat energy from one place to another, just like your refrigerator or air conditioner. But a major difference is that air conditioners and refrigerators transfer heat in only one direction, while a heat pump can transfer heat in two directions, thereby heating or cooling the space. In the cooling mode, the geothermal heat pump takes heat from indoors and transfers it to the colder earth through either groundwater or an underground earth loop system. In the heating mode, the process is reversed.

The buried pipe, or earth loop, is the most important technical advancement in heat pump technology to date. The idea to bury pipe in the ground to gather heat energy began in the 1940s. But it’s only been in the last twenty-five years that new heat pump designs and more durable pipe materials have been combined to make geothermal heat pumps the ultimate in efficiency. The two main types of loops available are open and closed. An open loop system is less expensive to install, but over time could require more maintenance. A closed loop system is more expensive up front, but requires almost no maintenance. As manufacturers phase out R-22 (HCFC) refrigerant, there have been more environmentally friendly liquid mediums brought into the marketplace to use in your system. The most common antifreeze solutions in the U.S. and Canada are propylene glycol, methyl alcohol, and ethyl alcohol.

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Author’s note: the following article on home heating is the third in an eight-part series. This article addresses climate conditions found in the San Francisco Bay Area, but may have applicability elsewhere.

Forced air systems are the most common heating systems in California and are used in most new construction elsewhere. They have two big advantages: they are cheap to install, and they provide heat at a moment’s notice. Having “instant-on” heat is vital for intermittent use spaces like ski cabins. Otherwise, forced air is the least energy efficient and least comfortable way of heating a typical home. Why?

Ventilation and Heat Loss

For the health and well-being of its occupants, a home must exhaust stale air and refresh it with new air drawn from outdoors. Forced air systems heat and blow this air, via ducts, throughout your house. Since new air is continually entering and leaving, you are heating the outdoors.

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Editor’s note: Today, we’re pleased to start a content partnership with GreenBuildingTalk, “the place to share, ask, and learn about green building products and methods.” The site’s forums are both active and informative, and they’ve now started blogging. Today’s post on solar hot water was originally published on May 5, 2008.

Each week, the Chicago Architecture Foundation and Chicago Green Technology Center graciously host “lunch time seminars,” inviting some of the leading industry professionals to discuss building issues they are involved with. On 5/1/08, they hosted Joe Gordon’s “Solar Hot Water and Heating- Is It Right for You?” presentation. The seminar provided the audience with information on how solar thermal works, how much space you’ll need, incentives, and how to determine cost benefits. Mr. Gordon also discussed how the cost of solar hot water and heating will likely keep increasing, due to the high cost of copper that is used in these systems.

Joe Gordon has worked for Solar Service, Inc. for over four years and has fielded thousands of inquires from developers, architects, owners and institutions about whether solar hot water and heating would work for them. Visit Solar Service’s gallery to see unique ways panels can be installed.

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