Dear EarthTalk: How energy efficient (and comfortable) is underfloor heating, sometimes known as radiant heating? -- Marcy Dell, Boston, MA
According to the U.S. Department of Energy, radiant under-
Underfloor radiant heating involves under laying the floor with a hot element or tubing that transfers heat into the room via infrared radiation and convection, obviating the need for forced or blowing air.
According to the U.S. Department of Energy’s Energy Savers website, radiant heating has a number of advantages over other forms of heat distribution: “It is more efficient than baseboard heating and usually more efficient than forced-air heating because no energy is lost through ducts.” It is also flexible as it can run off of a variety of energy sources: Gas, oil, wood, solar and other sources or combinations thereof can feed radiant systems. And radiant heating is a good choice for those with severe allergies as no potentially irritating particles get blown around the room.
Several aspects of radiant heating make it more energy efficient. For starters, the uniform heat distribution over the entire surface of a floor heats the lower half of the room, enveloping inhabitants in warmth at a lower overall temperature—in some cases up to five degrees Fahrenheit cooler—than a conventional heating system. “Radiators and other forms of ‘point’ heating circulate heat inefficiently and hence need to run for longer periods to obtain comfort levels,” reports the Residential Energy Services Network (RESNet). “They draw cold air across the floor and send warm air up to the ceiling, where it then falls, heating the room from the top down, creating drafts and circulating dust and allergens.” RESNet adds that radiant systems transmit heat on average some 15 percent more efficiently than conventional radiators.
The efficiency gains can be magnified significantly with good insulation and a well-designed system. While tearing out old heating systems and/or replacing decent existing flooring might be overkill for the sake of moving to radiant heat, those embarking on new building projects or contemplating major renovations should certainly consider it. According to TLC Network’s Green Living Guide, there are two main types of radiant heating, electric and hydronic. In the former, heated wires installed in the floor radiate heat upward.
This type of radiant heat is most commonly used to retrofit a single room—especially a bathroom or kitchen—in an older house or building. Meanwhile, hydronic radiant heating, whereby heated water is forced through tubes under the floor, is more often designed into a new structure from the get-go, and is more energy efficient overall.
TLC points out that while radiant heat is definitely more efficient in smaller, snug homes with lower roofs, it might not always be the greenest solution in homes with bigger rooms: “In some scenarios it can be less energy efficient than forced-air heating.” TLC recommends consulting with a reputable heating contractor to see if radiant heating is a sensible way to go.
Of course, pairing a radiant heating system with an energy efficient EnergySTAR-approved programmable thermostat can indeed save households hundreds of dollars a year on home heating bills while keeping inhabitants warmer all year long. Many states offer financial incentives to upgrade home and commercial heating systems in ways that boost energy efficiency. Check out the free Database of State Incentives for Renewable Energy (DSIRE) to find out what kinds of tax rebates or other incentives might be available in your neck of the woods.
CONTACTS: Energy Savers, www.energysavers.gov; RESNet, www.resnet.us; TLC Network Green Guide, http://tlc.howstuffworks.com/home/green-living.htm; DSIRE Database, www.dsireusa.org.
Dear EarthTalk: Are there certain brands or retail stores where sustainable furniture options can be had? And what should I look for when shopping for greener furniture? -- W. Cary, Trenton, NJ
Thanks to increased consumer awareness and demand, there are more
While we now opt often for greener cars, appliances, household cleaners and food to up the sustainability quotient of our lifestyles, the furniture we spend all day and night in close contact with is often far from eco-friendly. The vast majority of sofas, chairs, beds and other upholstered furniture we love to lounge on contain potentially carcinogenic formaldehyde and/or toxic flame retardants and stain resistors that have been linked to developmental and hormonal maladies. And much of the wood used in desks, chairs, tables and the like (as well as in the frames of upholstered furniture) comes from unsustainably harvested lumber which contributes to the deforestation of tropical rainforests.
But today, thanks to increased consumer awareness and demand, there are more “green” choices in furniture available than ever before. A good place to start the search for that perfect couch or chair is the website of the Sustainable Furniture Council (SFC), a non-profit formed in 2006 to help develop solid standards and certification processes within the home furnishings industry. The organization has become a leading information source and network of some 400 “green” furniture makers and related retailers, suppliers and designers as well as other non-profits. Consumers looking for greener furniture can browse SFC’s membership list which features contact information and website links accordingly. Buyers beware: Just because a furniture maker is listed with SFC doesn’t mean it eschews all chemicals or unsustainably harvested wood entirely, but only that it is making strides in that direction. Consumers should still be knowledgeable about which green features they are looking for and/or which kinds of materials to avoid.
Of course, with something like furniture you really need to see and feel it in order to decide whether it will work in your space. Eco-conscious consumers making the rounds at local furniture stores should keep a few key questions in mind for salespersons. Does the piece in question contain formaldehyde, flame retardants or stain resistant sprays? Is the fabric used certified under the Global Organic Textile Standard program (GOTS, which mandates that at least 70 percent of fibers are derived from organic sources and do not contain chemical dyes or other additives)? Is the wood used certified by the Forest Stewardship Council (FSC) as sustainably harvested? Does the piece contain any parts or pieces that come from bamboo or reclaimed wood or recycled metal or plastic? And is it easy to disassemble into reusable or recyclable parts if it needs to be replaced down the line?
If the salesperson doesn’t know the answers, chances are the piece does not pass environmental muster. Limiting your search to brick-and-mortar and Internet-based retailers that specialize in green products is one way to reduce the amount of research and self-education needed, especially because salespersons in such stores are usually up-to-speed on the latest and greatest in sustainable furnishings. Some leading national furniture chains that carry a sizeable inventory of sustainable goods include Crate and Barrel, Room and Board and West Elm, but many more single store eco-friendly furniture stores exist across the country. Some leading online green furniture retailers include Eco-Friendly Modern Living, Furnature, InMod, Mitchell Gold + Bob Williams, SmartDeco, Southcone and Viesso.
CONTACTS: SFC, www.sustainablefurnishings.org; FSC, www.fsc.org; GOTS, www.global-standard.org; Eco-Friendly Modern Living, www.eco-friendlymodernliving.com; Furnature, www.furnature.com; InMod, www.inmod.com; Mitchell Gold + Bob Williams, www.mgbwhome.com; SmartDeco, www.smartdecofurniture.com; Southcone, www.southcone.com; Viesso, www.viesso.com.