This article was originally published in the November/December 1994 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.



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Home Energy Magazine Online November/December 1994



Consumers Union's Test Methods

First, congratulations to Home Energy on its tenth anniversary. The magazine continues to be informative, insightful, and often provocative. Many of us at Consumers Union look forward to Home Energy every other month. Keep up the good work.

Second, I take issue with your statement that occasionally Consumer Reports will publish the test results of an isolated device, but the magazine has been lamentably unsophisticated in its evaluations of electronic thermostats and other devices. I fear that you are unaware of the breadth of testing that goes on behind the scenes at Consumers Union (see The GreenPlug Dilemma, HE Sep/Oct '94, p.2).

For instance, with electronic thermostats (Consumer Reports, Oct '93), we conducted tests with five samples of each model in an environmental chamber for temperature accuracy and to measure temperature differentials. Tests were also conducted in a chamber where the thermostat controlled the heating system to observe the differential and control switching. The thermostats were also used in six homes with four different types of heating systems, where the thermostat's operation was monitored every ten minutes for up to two weeks. Finally, we conducted power-failure and battery-replacement tests. In addition to these tests, we made judgements regarding ease of installation, ease of programming, and even described what to do with one's old mercury-bulb thermostat.

All of this research is internally published (and avidly checked) in a very detailed technical report. In order to make our findings clear to our non-technical audience, our articles in Consumer Reports must often omit details that engineers and scientists would find fascinating.

Mark Connelly
Director of Testing
Home Environmental Products
Consumers Union
Yonkers, New York


The GreenPlug Predicament

We read your editorial, The GreenPlug Dilemma with great interest, and share your concern for products that promise savings but do not deliver.

The difficulty in testing any energy-saving product is that ultimately, the consumer uses it in conditions which are rarely, if ever, static. This quandary is not unique to energy-saving devices such as the GreenPlug, but is experienced in a wide range of consumer products, from cars (gas mileage) to shingles (warranty life). It is interesting to note in the same issue of Home Energy a letter from Sun Frost concerning the use of Department of Energy test chambers at 90deg.F (which is done to simulate door openings), when in actual conditions 70deg.F ambient is more likely.

As the utility distributor for GreenPlug, and a subsidiary of Central Vermont Public Service, we are acutely aware of the need for verifiable claims as to energy savings. It is for this reason that SmartEnergy and Green Technologies have been collecting data from a wide variety of sources regarding the GreenPlug's effectiveness. These field tests are being coupled with statistical analyses by Barakat and Chamberlin to determine, with more precision, savings a specific refrigerator will achieve with the GreenPlug.

Without these independent tests and matching statistical profiles, we wholeheartedly agree it would be impossible to make blanket statements about a product's guaranteed savings. This is similar to the compact fluorescent lightbulb quandary: the bulbs do save money if applied properly (in fixtures running for at least two hours) but do not pay for themselves if misapplied and placed in locations such as basements, garages, and so on.

The determination of savings by an individual consumer from a product such as a CFL or GreenPlug is difficult to ascertain, but an estimate can be based on test data spread across a larger population. In the case of the GreenPlug, the higher the incoming line voltage, the greater the savings and the quicker the payback period. However, this does not mean there are no savings for low voltage conditions, just that the percentage saved is smaller. The other consumer benefits of the product--quieter operation and lower operating temperatures--still apply.

Another point of interest is the term old refrigerator. Our testing survey found GreenPlug savings with makes and models even up to about 1993, when smaller motors became the norm. Given the average age of refrigerators (between 12 and 15 years), a large percentage of the 120 million units on the market could dramatically benefit from the use of an energy-saving device such as a GreenPlug.

We disagree with your assertion that the energy savings are only available in unusual circumstances. Given the target range of 120 volts around the United States, as an average, and the GreenPlug's ability to trim incoming voltage to 106 volts, chances are very good that some savings will occur.

Mark Gabriel
Vice President/General Manager
SmartEnergy Services Inc.
Rutland, Vermont


The Takeback Controversy

I write to add to the takeback controversy (see What Takeback Effect? HE May/June '94, p.5). In a 1991 study of the Northgate Apartments renovation and fuel-switching project in Burlington, Vermont, we found a takeback effect of 14%, due to residential heating increases (see Making Low Income Housing Affordable: The Northgate Retrofits, HE Mar/Apr '93, p.13.). Residents raised their thermostat temperature by an average of 9deg.F. To document this, we surveyed residents and verified results with DOE-2 and PRISM analyses. There were energy savings from the project, but not the predicted 22%.

The primary reasons for the dramatic difference were the high cost of electric heat, low setpoints prior to the retrofits, and the fewer and larger zones of the new hydronic heating systems. Tenants' previous average thermostat setpoints were a cool 59deg.F, and they still had average winter heat bills of $225. Is it any wonder that once the electric baseboard was replaced by gas-fired hot water, people chose to be more comfortable? Average temperature settings among Northgate's tenants are now 68deg.F, and average winter-heating bills are approximately $110.

This example occured in a cold climate, which runs counter to the suggestion that takeback is more likely in moderate climates. We concluded that the change of the heating systems and the cost difference between them account for the takeback effect. But the Northgate site still had a net 5%-7% energy savings at the meter and a source-energy reduction of 47%.

If you deal with a fuel-switching project with high cost differentials, plan on some takeback in the residential heating load. It's better to account for such effects in the design phase of a program than to justify them after the effect is documented.

Chip Patullo
Burlington, Vermont


More on CO Poisoning

I read with interest about the deaths of two children in Saskatoon, Canada, from carbon monoxide poisoning (see Conservation Clips, HE July/Aug '94, p.45). I thought your readers would be interested in more information about the incident.

The house in which the people died was a 1975 home with two-by-four walls and no special air-tightness features. It was not the airtightness of the house that caused the death of the children, but rather a combination of the failed Class A chimney, cold outside temperatures (approaching -35deg.F for several weeks), and a faulty furnace. The people in the house had placed polyethylene on the aluminum-framed windows, not for energy-conservation reasons but to try to control condensation problems caused by the blocked chimney. The blocked chimney caused the furnace to dump the exhaust gases into the house via the draft diverter on the gas furnace. The chimney had been partially blocked for months. A 100,000 Btu per hour furnace running continuously will produce about 10 pounds of water per hour.

Since 1986, Class A chimneys have not been allowed with natural gas furnaces in Saskatchewan, because of failures. Yet an estimated 100,000 Saskatchewan homes still have them. It appears that a key reason why some chimneys fail is that the furnace burners have too short a cycle time. According to an experienced furnace installer, furnace burner on-times should be at least 6 minutes in colder weather. Shorter cycles do not allow the upper part of the chimney enough time to evaporate the condensation that occurs in the early part of the furnace burn cycle.

Natural gas furnaces, particularly the older atmospheric-vented units, have been very reliable. Consequently, most people overlook preventive maintenance and safety checks. Incidents like the one in Saskatoon will hopefully spur people to do more of these checks. The local gas utility is now recommending that people visually check their chimneys twice a year and have their furnaces checked once a year by a qualified service person.

Robert S. Dumont
Saskatoon, Saskatchewan




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