Every day, marketers convince hundreds of people to spend money on useless “energy saving” gadgets. Since these marketers show no signs of going away, it’s time to highlight their products with a ten-worst list.
The order of the products described in the following list is random. I had to remove an eleventh item from this list: “insulating” paints, a product category that I debunked in a recent blog. If you know of a deserving product that should have been included in this list, feel free to post nominations for the list’s second edition.
The Ten Most Useless Energy-Related Products
1. Tyvek ThermaWrap
In 2006, this “low-e” housewrap suffered from a disastrous launch by bumbling DuPont marketers who bragged that the “insulating” properties of the housewrap were due in part to its low emissivity. Reviewing the product for Energy Design Update, I asked ThermaWrap representatives to specify the emissivity of the membrane, only to be told that “due to company policy,” DuPont was “not at liberty to reveal the actual emissivity number for Tyvek ThermaWrap.”
Later, when my journalistic investigations revealed that DuPont had failed to produce a ThermaWrap fact sheet as required by the Federal R-Value Rule, DuPont reluctantly admitted that ThermaWrap has an emissivity of 0.2 — exactly the same value that EDU predicted in its September 2006 review. The emissivity of ThermaWrap is too high to qualify as either a radiant barrier or a reflective insulation.
DuPont no longer repeats its earlier claim that “Tyvek ThermaWrap changes the dynamics of heat flow across the entire wall system and dramatically helps improve the insulating value of the wall system.” In fact, if ThermaWrap is installed facing an air space, it will change the R-value of the air space from R-1 to R-2 — a change that few would characterize as “dramatic.” In response to my reporting, ThermaWrap’s product manager eventually wrote EDU a letter noting that “DuPont regrets any lack of clarity in its DuPont Tyvek ThermaWrap literature, as well as the incomplete nature of the information supplied to EDU.”
2. Fafco plastic solar collectors
A California manufacturer, Fafco, produces an unglazed plastic solar collector called the Hot2o. Although plastic solar collectors are often used to heat swimming pools, the Hot2o is marketed for domestic hot water systems, which require much higher temperatures than swimming pools. The Hot2o collector has an expected lifespan of only 12 or 15 years, and it will never be able to heat water to the same high temperatures as a glazed collector.
Even the founder of the company, Freeman Ford, admits that “it represents a value breakthrough, not an efficiency breakthrough.” My own advice: save your money until you can afford a glazed collector.
3. Passive fresh air inlets
These small round vents are basically holes in the wall. Produced by several manufacturers — including Airex, American Aldes, Condar, Panasonic, and Therm-Stor — these vents are supposed to provide a way for fresh outdoor air to enter a home whenever exhaust fans are operating. Unfortunately, air responds to pressure differences; it doesn’t obey the “smart arrows” in the diagrams. That’s why air is just as likely to exit the vents as to enter.
Researchers have shown that almost all houses have enough random air leaks to allow exhaust fans to operate without these useless devices. More information on passive air inlets can be found here.
4. Vinyl siding laminated to rigid foam
Manufacturers have figured out how to laminate vinyl siding directly to thin pieces of expanded polystyrene (EPS) insulation. “Insulated” vinyl siding is available from several manufacturers, including CertainTeed, Crane Plastics, Heartland, Norandex-Reynolds, and Resource Materials Corporation. Don’t expect “insulated” vinyl siding to add much R-value — most of these products are in the R-3 to R-4 range. The real problem with the product is that the flat-backed foam fills the corrugated air space behind the siding, limiting drainage and reducing the wall’s drying potential.
In other words, the added foam interferes with one of the best aspects of vinyl siding: its built-in rainscreen.
5. Powered attic ventilators
Powered attic ventilators are exhaust fans installed in an attic to keep the attic cool. Whether powered by ordinary 120 volts AC or by a solar panel, powered attic ventilators are a waste of money. Since most U.S. homes have leaky ceilings, powered attic ventilators commonly draw conditioned indoor air into the attic through ceiling cracks, increasing energy costs.
Attic ventilators are powerful enough to depressurize a house, potentially causing water heaters to backdraft. Instead of wasting your money on a powered attic ventilator, you’d be better off spending your money on canned foam to seal leaks in your ceiling — or, if your ceiling is already airtight, on additional insulation for your attic floor. For more information on these useless gadgets, see Fans in the Attic: Do They Help or Do They Hurt?
6. Programmable thermostats
Okay, these devices aren’t really useless — they’re just unnecessary and insufficient. I’m happy to stipulate that anyone who actually programs and uses a programmable thermostat will save energy compared to someone who never performs thermostat setbacks.
That said, study after study has shown that installing programmable thermostats makes no difference in energy use. The reasons are simple: when it comes to thermostat setbacks, homeowner behavior is far more important than the hardware on the wall, and many homeowners are frustrated by the difficulty of programming these devices.
Plenty of homeowners with simple non-programmable thermostats routinely set back their thermostats when they go to bed or leave for work, while the majority of homeowners with programmable thermostats never use them. So here’s the bottom line: whether you have a simple Honeywell Round or a complicated electronic gizmo on your wall, it’s important to set back your thermostat. The hardware you use is irrelevant.
7. Inexpensive LED lamps
Most LED lamps on the market are less efficient than compact fluorescent lamps (CFLs), which have an efficiency of 48 to 60 lumens per watt. (By the way, straight T-5 and T-8 fluorescent tubes are even better than CFLs, with efficiencies of 98 to 105 lumens per watt.) Although the best LED lamps on the market are about equal in performance to CFLs — Cree produces LED downlights rated at 46 to 60 lumens per watt — they cost significantly more than CFLs.
The majority of LED lighting products on the market produce only 10 and 19 lumens per watt — about the same as an incandescent bulb. Moreover, testing of LED lights by the U.S. Department of Energy in 2006 and 2007 revealed that most LED manufacturers were exaggerating lumen output. LED devices that were touted as producing 36 to 55 lumens per watt actually produced only 11.6 to 19.3 lumens per watt. Caveat emptor.
[Author’s postscript, December 2013: In the four years since this article was written, the quality and efficiency of LED lamps has improved and prices have dropped. It now makes sense to consider LED lamps for many applications, especially for down-lights that require a directed beam.]
8. Foil-faced bubble wrap
Distributors of foil-faced bubble wrap “insulation” have a rich history of exaggeration and fraud. A September 2003 exposé in Energy Design Update documented several wild exaggerations by manufacturers. Although foil-faced bubble wrap has an R-value of about 1 or perhaps 2, several manufacturers have falsely claimed R-values ranging from 5 to 10.
In hopes of avoiding FTC enforcement action, the manufacturers, caught red-handed, sent EDU a comical cavalcade of apology letters. The bottom line: foil-faced bubble wrap costs just as much as — and in some cases much more than — 1-inch-thick rigid foam. As building scientist John Straube pointed out, “I might recommend it if it were half the price of R-5 rigid foam, but if it costs more than R-5 foam then you have to be crazy or stupid to use it.”
9. Power factor correction devices
These “black boxes” — brand names include the KVAR Power Factor Optimizer and the Power-Save 1200 — purport to provide energy savings by correcting the power factor of electricity. Some of these devices are intended to be “whole-house” boxes, while others are designed to “correct” the power factor of an individual plug-in appliance. Manufacturers claim that the gadgets reduce the amount of electricity used by appliances with coils or capacitors (pumps, fans, and fluorescent light ballasts) with power factors less than 1 — that is, appliances with electricity wave forms with the current and voltage out of phase.
But residential customers aren’t even billed by power factor — residential electricity meters can’t even measure it. Since homeowners aren’t penalized for low power factors, these devices can’t possibly save you any money. To learn more about this scam, see or
10. Vent-free gas space heaters
Like powered attic ventilators, so-called “vent-free” gas space heaters deserve a special award, since they’re not just useless — they’re potentially dangerous. Several critics have pointed out that these appliances aren’t really vent-free — they just use your living room (and your lungs) as a chimney.
Illegal in California, these heaters shouldn’t be used anywhere. To learn more, see Alex Wilson’s recent blog, “Avoid Unvented Gas Heaters.”
Last week’s blog: “Pinpointing Leaks With a Fog Machine.”