Dos and don'ts on portable heaters It may be cheaper and safer to extend the hot-air ductwork


November 24, 1996|By Karol V. Menzie and Randy Johnson

THE FIRST REAL cold snap of the year always brings out mittens and parkas, and it also brings out any problems with a home's heating system.

And sometimes, even though the problem may be recurrent, a solution can prove elusive. That's the situation for a woman in South Baltimore who wrote recently about problems with a space heater in the bathroom of the rowhouse where she's lived for 40 years.

"Our furnace was put in about nine or 10 years ago," she wrote. "The problem is that we didn't run heating ducts to the upstairs." Before the furnace was installed, the family used unvented gas space heaters. Now the heaters have been replaced everywhere except the bathroom at the back of the second floor.

But that bathroom heater didn't work; the pilot light kept going out. The company that made the heater said it would not work without ventilation. So the reader has been using an electric heater. However, she has to use an extension cord, because there's no outlet in the bathroom. And the heater has to be used sparingly, she said, because it is expensive.

Her questions: "What kind of heater should be put in the bathroom without running heating ducts up to it? And what is meant by ventilation to keep the pilot light from going out?"

We see several problems here. One is with the concept of vent-free space heaters: Although they are a good source of heat, they can produce dangerous levels of carbon monoxide. Newer vent-free units are somewhat safer than the older ones, but they still bear monitoring.

Baltimore City considers vent-free gas space heaters so dangerous it has made them illegal (including the newer models), along with unvented kerosene heaters. Operating a heater that's illegal in your jurisdiction can result in problems beyond the danger of carbon monoxide buildup: It can lead to fire insurance being voided, or result in fines if it's discovered.

Although we're not sure why the pilot light kept going out on the reader's most recent gas heater, there are two possible reasons -- neither of them good.

All gas space heaters use air to burn. Newer ones have an oxygen-depletion sensor, or ODS, that shuts off the unit if there's too little oxygen in the air to burn (for instance, if carbon monoxide levels have built up).

Ventilation -- that is, a chimney vented to the outside -- allows carbon monoxide and other gases to escape. But in the reader's case, either there is not enough ventilation to keep the gas heater burning, so the pilot light goes out, or the unit has an oxygen sensor that is detecting too-low levels of oxygen and shutting off the pilot light.

Either way, it means the unit should not be used in this space.

An electric heater is not a good alternative for a bathroom because of the danger of electrocution. Adults may know not to place the heater where it can plunge into a tub or sink full of water, but children may not.

If there are no children in the house, if the extension cord is a larger diameter than the heater cord and is unplugged when the heater is not in use, if the plugs on the heater and extension cord are checked to make sure they're not overheating, if no cords run under a rug, if the heater is kept away from water sources, then it might be safe to use in a bathroom -- until other heating arrangements can be made.

Modern kitchen and bath wiring includes ground-fault outlets that shut down the electricity when they detect a release of ungrounded current -- such as a heater falling into a tub.

But even ground fault receptacles are no substitute for common sense. Cords should be unplugged when appliances are not being used. Even if they're turned off, there is still 15 amps of current running to the switch on the appliance, and 15 amps is more than enough to be deadly.

One safe way to put an electric heater in the bathroom would be to install it permanently on the wall, wired permanently into its own circuit. Alternatively, there are oil-filled units that work like radiators and are more economical to use than electric-resistance types, which have air blowing across heated wires.

The reader wanted to install a heater that wouldn't require running ductwork to the bathroom, but in fact, that may be the most economical course. The cost of buying an electric heater bTC

and running wiring to the bath could be twice as much as the cost of extending the ductwork.

The duct to a bathroom does not have to be large; you could run a 4-inch oval duct up in a corner of the room below and box it in with drywall. A professional should have no problem figuring out the size of the duct needed, based on the size of the room, length of exterior walls, and size of the window opening.

And finally, excuse the soap box, but we'd like to remind everyone who burns fossil fuels -- oil, gas, wood or coal -- to monitor the home's carbon monoxide.

CO detectors cost about $50. We like the ones that plug into the wall and provide a constant digital readout. That way, if something in the readout changes, you can act quickly to find and correct the problem, even if the CO levels are not high enough to trip the alarm.

Randy Johnson is a Baltimore home-improvement contractor. Karol Menzie is a feature writer for The Sun.

If you have questions, tips or experiences to share about working on houses, e-mail us at, or write to us c/o HOMEWORK, The Sun, 501 N. Calvert St., Baltimore 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.

Pub Date: 11/24/96

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