Cold, Cold Facts About Heat Pumps


February 06, 1994|By MIKE BURNS

A lot of shivering homeowners in this winter of our discontent have discovered a new oxymoron: heat pump. Because it doesn't pump heat, it pumps cold air across an already chill skin.

Actually, oxymoron is one of the less offensive terms we've heard thrown at those super-hyped, eco-energy-efficient inventions that claim to save the planet and your pocketbook. Wait until the electric power bills come in this year and you'll hear even louder howls.

You can't dispute the advertising appeal of these devices, which are designed for both heating and cooling. Heat pumps are in 30 percent of Maryland homes -- double the percentage rate a dozen years ago.

Trouble is, most of these heat pumps are not doing the job they were designed to do. This record-cold winter, which is not exceptionally colder than some other recent winters, unmasked the deficiencies of heat pumps with icy candor.

First of all, it's questionable whether Maryland has a warm

enough climate to use the most common version of the heat pump, the air-to-air variety.

Consultants tell us that the Federal Housing Administration considers North Carolina the northernmost state for effective use of heat pumps. In fact, the general advice on heat pumps is that they do best in a place with mild winters and long summers -- leaving that judgment up to the consumer or the homebuilder.

When temperatures dip below 40 degrees -- and it has been rare when that didn't happen for much of any day this season -- the basic heating element of the heat pump begins to lose its efficiency, and its claimed energy savings shrink.

That's when the supplemental electrical heating unit in the blower kicks on (or is turned on) to warm up that air. Like electric space heaters, the auxiliary heater is expensive and an inefficient user of power.

That's probably one large reason why we had those electric-demand peaks, and rolling blackouts, last month: increased use of heat pumps in the most inefficient manner.

Geothermal, or ground-source, heat pumps are less fickle in colder weather and can save noticeable amounts of power. But they cost at least twice as much as air-to-air units, and require a substantial amount of land to bury their closed-loop pipes in the ground. The odds are that if you have a heat pump, it's not that kind.

Even then, the air coming out of any heat pump feels cooler than furnace air. Its temperature is cooler than that of the human body, about 90 degrees compared with 120 degrees for furnace heat, which certainly affects the comfort level.

Another major problem with heat pumps is improper installation and inadequate maintenance. Leaky duct work, leaky refrigeration systems, wrong pressure settings for the refrigerant and faulty thermostats are some of the installation defects found in customer surveys by Virginia Power and Pacific Gas & Electric. Heat pump homes need tighter insulation, too.

Homeowners get blamed for failing to provide semi-annual or even annual maintenance of these sensitive systems, which need a lot more attention than gas- or oil-fired furnaces. It's a shock to new owners who did no more than change the air filters on their furnace systems.

The experts also tell you to clear all the ice off the outside heat pump unit so that it will function -- not the most welcome advice when you need a chisel and sledgehammer to chip through the gelid coating and the wind-chill is below zero.

So while heat pumps may work well in principle, and under ideal conditions, they don't appear to meet the test of cold winters under typical homeowner conditions around here.

We're not debating here the relative BTU-content and comparative costs of electricity, natural gas or oil, nor are we discussing equipment efficiency. We're talking basic heating, and the most inefficient way to get it. The complaints we hear are that heat pumps don't crank out the heat they are supposed to provide. It's a gripe you seldom hear about standard furnaces or boilers, even the older, less-efficient models. Heaters are supposed to heat, period.

You might ask why there are so many heat pumps in this border region. First and foremost, they are cheaper, a third less costly than a paired furnace and air conditioning system, so builders like them and consumers are easily convinced.

Then there are rebates from Baltimore Gas & Electric Co. for installing a heat pump. And all BG&E customers pay for those rebates via a state-authorized surcharge. That regulatory effort to conserve energy through heat pumps may well have backfired. In fact, BG&E openly promotes expanded gas lines as a power-conservation measure.

Heat pumps were strongly pushed in the 1970s and into the early 1980s during shortages, and subsequently sky-high prices, for natural gas. Gas companies wouldn't extend their distribution lines. New homes had to choose between electricity and oil heating; all-electric was an easy, economical choice.

Fifteen years ago, more than half the new homes were built with heat pumps. Today, that figure has plummeted to one-quarter, as consumers have flocked to natural gas and gas supplies again have become reliable. BG&E began promoting expanded gas sales anew four years ago, after years of touting the advantages of the heat pump. The company still says that newer heat pumps are efficient, and cheaper to run than oil furnaces, if properly maintained. But that's truly cold comfort, as many pump owners have found this year.

Mike Burns is The Baltimore Sun's editorial writer in Harford County.

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