Radiant Heating

Radiant heating systems involve supplying heat directly to the floor or to panels in the wall or ceiling of a house. The systems depend largely on radiant heat transfer: the delivery of heat directly from the hot surface to the people and objects in the room via the radiation of heat, which is also called infrared radiation. Radiant heating is the effect you feel when you can feel the warmth of a hot stovetop element from across the room. When radiant heating is located in the floor, it is often called radiant floor heating or simply floor heating.

Radiant heating has a number of advantages: it is more efficient than baseboard heating and usually more efficient than forced-air heating because no energy is lost through ducts. The lack of moving air can also be advantageous to people with severe allergies. Hydronic (liquid-based) systems use little electricity, a benefit for homes off the power grid or in areas with high electricity prices. The hydronic systems can also be heated with a wide variety of energy sources, including standard gas- or oil-fired boilers, wood-fired boilers, solar water heaters, or some combination of these heat sources.

Despite their name, radiant floor heating systems also depend heavily on convection, the natural circulation of heat within a room, caused by heat rising from the floor. Radiant floor heating systems are significantly different than the radiant panels used in walls and ceilings. For this reason, the following sections discuss radiant floor heat and radiant panels separately.

Radiant Floor Heat
There are three types of radiant floor heat: radiant air floors (air is the heat-carrying medium); electric radiant floors; and hot water (hydronic) radiant floors. All three types can be further subdivided by the type of installation: those that make use of the large thermal mass of a concrete slab floor or lightweight concrete over a wooden subfloor (these are called "wet installations"); and those in which the installer "sandwiches" the radiant floor tubing between two layers of plywood or attaches the tubing under the finished floor or subfloor ("dry installations").

Types of Radiant Floor Heat

Air-Heated Radiant Floors
Because air cannot hold large amounts of heat, radiant air floors are not cost-effective in residential applications, and are seldom installed. Although they can be combined with solar air heating systems, those systems suffer from the obvious drawback of only being available in the daytime, when heating loads are generally lower. Because of the inefficiency of trying to heat a home with a conventional furnace by pumping air through the floors, the benefits of using solar heat during the day are outweighed by the disadvantages of using the conventional system at night. Although some early solar air heating systems used rocks as a heat-storage medium, this approach is not recommended. For further information, see the section on solar air heating systems.

Electric Radiant Floors
Electric radiant floors typically consist of electric cables built into the floor. Systems that feature mats of electrically conductive plastic are also available, and are mounted onto the subfloor below a floor covering such as tile. Because of the relatively high cost of electricity, electric radiant floors are usually only cost-effective if they include a significant thermal mass, such as a thick concrete floor, and your electric utility company offers time-of-use rates. Time-of-use rates allow you to "charge" the concrete floor with heat during off-peak hours (approximately 9 p.m. to 6 a.m.). If the floor's thermal mass is large enough, the heat stored in it will keep the house comfortable for eight to ten hours, without any further electrical input (particularly when daytime temperatures are significantly warmer than nighttime temperatures). This saves a considerable number of energy dollars compared to heating at peak electric rates during the day.

Electric radiant floors may also make sense for additions onto homes for which it would be impractical to extend the heating system into the addition. However, homeowners should examine other options, such as mini-split heat pumps, which operate more efficiently and have the advantage of also providing cooling.

Hydronic Radiant Floors
Hydronic (liquid) systems are the most popular and cost-effective radiant heating systems for heating-dominated climates. Hydronic radiant floor systems pump heated water from a boiler through tubing laid in a pattern underneath the floor. In some systems, the temperature in each room is controlled by regulating the flow of hot water through each tubing loop. This is done by a system of zoning valves or pumps and thermostats. The cost of installing a hydronic radiant floor varies by location and also depends on the size of the home, the type of installation, the floor covering, remoteness of the site, and the cost of labor.

For more information on radiant panels, visit http://www.radiantpanelassociation.org

For radiant flooring resources and installers in and around the Bay Area, please feel free to contact me by phone or email.

Information on radiant heating systems provided by the US Department of Energy (http://www.eere.energy.gov)

Remodeling “Green” can earn you more green when time to sell

It goes without saying that the housing market is in one of the tougher periods experienced in decades, a period not seen since the Great Depression (according to those that draw such comparisons). In fact, experts have predicted that 2008 sales could be down more than 40% from their peak of a few years ago.

The question remains though . . . what if you really need to sell your home right now? What if the need to relocate requires you to sell, or perhaps the desire to buy a bigger home due to an ever-increasing family size? Quite simply, what if you can't afford to wait until the market improves?

The good news is you have the ability to do work on your home that puts you head and shoulders above the other houses for sale in your price range by making smart and quick eco-renovations, i.e. remodeling/renovating/upgrading “green”. In a market such as this one where buyers are looking for added value in their every purchase, making smart green remodeling tweaks invariably makes your home more competitive, not to mention reducing your energy bills, reducing your water waste, improving your indoor air quality, and bettering the fate of the planet.

Here for you now are a handful of ways to make your “green” house stand out from the rest:

Do it yourself projects
• Save Energy—Plant trees to provide necessary shade
• Seal all exterior holes leading in with better caulk
• Repaint using Low-VOC or No-VOC paints
• Replace older, single pane windows with double pane windows
• Add more insulation to walls, ceilings, attic
• Install a water heater timer
• Install a programmable thermostat
• Install a ceiling fan to improve efficiency
• Install energy efficient lighting

Projects requiring a contractor
• Install new green flooring; be it natural fiber carpet, cork, bamboo, sustainable or reclaimed wood
• Install energy recovery ventilators
• Install a tankless water heaters
• Retrofit radiant heat
• Have an energy audit and thermographic inspection
• Install a whole house fan

Obviously there are assorted other green remodeling tips one could take on with the simple concept in mind that any of the above will invariably increase your home’s value and make those living in your home healthier and happier.

Pacific Coast Builders Conference Announces Top Five Green Products

Pacific Coast Builders Conference is home building's premier tradeshow and conference — an annual event bringing together the people who imagine, design and create our neighborhoods and communities of the future. Held every June in San Francisco, PCBC draws over 26,000 residential builders, developers, architects, financiers, product manufacturers, and consultants from the industry.

At the recently completed show, members of the home building industry voted and named the “coolest” homebuilding products in the annual Cool Products contest. Exhibitors entered more than 125 products in three categories - Consumer, Green and Industry products. Five products were chosen for each category by 679 home building professionals who voted online. All companies, products and more information is available at www.pcbc.com/cool.

To follow are the Cool Products from the Green Category for 2008

1. Rinnai Corporation’s Rinnai LS Series Tankless Water Heater - Offers 30% to 50% energy savings over traditional tank-style units and can supply hot water when you need it, for as long as you need it, while contributing to a greener environment.

2. Eagle Roofing Products’ Eagle Solar Roof powered by SolarSave Integrated Solutions - This solar system integrates seamlessly with Eagle concrete roof tile and maintains the aesthetics of the roof, maintains the integrity of the roof system, prevents leaks and protects the home or building.

3. Cree LED Lighting Solutions LR6 Light Bulb - Has a 20-year life span (50,000 hours under normal use) and 85% less energy than a conventional incandescent and less than half that of a comparable fluorescent.

4. Akeena Solar’s Andalay Solar Panels - Uses a Lego-like, snap-in-place process to lie flat on rooftops. The Andalay panels have 70% fewer parts than a conventional system and 20% fewer rooftop penetrations.

5. The new GE Profile SmartDispense Frontload Washer and Dryer - Uses as little as 10 gallons of water and stores and automatically dispenses detergent and fabric softener based on each load’s size, soil level, water hardness and fabric or cycle type.

Green Product Directories

An important tool in the effort to build greener buildings and live greener lives is the selection of products that were made using environmentally friendly processes and are used in environmentally friendly ways.

Green products are available for just about any daily need, and the ways they are green are many and varied: They are energy or water efficient; they use healthy, non-toxic materials; they are made from recycled or renewable sources; they make current products you use more efficient or more durable; and they are recyclable or biodegradable, among many other things.

But among all the truly green products comes the risk of "greenwashing;" that is, products that are advertised as green without truly offering environmental or health benefits. The directories below will help you sort through the claims and find the products that best meet your needs. But please note: Inclusion or exclusion of any product in these directories does not represent endorsement by the U.S. Green Building Council.

ENERGY STAR: Products in more than 50 categories are eligible for the ENERGY STAR. They use less energy, save money, and help protect the environment. ENERGY STAR is a program of the U.S. Environmental Protection Agency and the U.S. Department of Energy.
http://www.energystar.gov/index.cfm?fuseaction=find_a_product.

Good To Be Green: Good To Be Green is a directory of green building products, sustainable building materials and green building service providers. Products must: be made out of recycled materials; ensure a low environmental impact during the construction, operation and/or demolition of the building; conserve natural resources like energy, wood and water; and improve air quality.
http://www.goodtobegreen.com

Green2Green: Green2Green.org features comprehensive information regarding green building products, materials and practices. The site offers side-by-side comparisons of products using a variety of environmental, technical and economic criteria.
http://www.green2green.org

Green Building Pages: Green Building Pages is an online sustainable design and decision-making tool for building industry professionals and environmentally and socially responsible consumers.
http://www.greenbuildingpages.com/

The Green Guide: National Geographic's Green Guide offers staff-written reviews of a host of products, ranging from appliances, home furnishings and home improvement products to personal care and pet supplies.
http://www.thegreenguide.com/products

GreenSpec Directory: The online GreenSpec® Directory lists product descriptions for over 2,100 environmentally preferable products. Products are chosen to be listed by BuildingGreen editors. They do not charge for listings or sell ads.
http://www.buildinggreen.com/menus

Low Impact Living: Find environmentally friendly products and services in dozens of categories.
http://www.lowimpactliving.com/products-providers

Oikos: Oikos is a World Wide Web site devoted to serving professionals whose work promotes sustainable design and construction.
http://www.oikos.com

PlugGREEN: PlugGREEN.com allows green businesses to create their own business profile, allowing them to network directly with other green businesses and green-minded consumers. In addition, PlugGREEN.com provides an organized and efficient way for consumers to find local green businesses and products in their area.
http://www.pluggreen.com