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Boston Furnace Replacement Considerations

The decision to replace a furnace can be difficult. If the decision to replace hasn’t already been made by circumstance, cost is the usually primary factor in the decision. Can you afford to replace your heating equipment, or can you get one more season out of the old furnace? Boston homes need heating equipment that can tolerate a tough winter, so what should you look at when considering replacement?

The cost of the replacement is certainly a consideration. Many homeowners choose to upgrade (or install) their central air conditioning unit at the same time they change out their heating equipment. While this isn’t strictly necessary, depending upon the type of heating system in the home, homeowners can save thousands of dollars by redoing the heating and cooling at the same time.

The cost of operation is also a consideration. For homeowners with oil furnaces, or oil-fed boilers, the cost of heating oil has risen sharply and steadily while the cost of other heating fuels has remained relatively constant. Heating oil is nearing $4 per gallon now, and this rise in price is stirring bad memories of 2008, when the price of heating oil (at times) was nearing a whopping $5 per gallon. Natural gas furnaces can heat the same space for about 2/3 the current cost of heating oil, and the cost of natural gas is expected to remain steady. (In fact, it’s dropped about 2% in the last 12 months.)

Electric heaters are also very cost-intensive, and because most electricity is produced from coal-fired plants, the carbon emissions related to electric heat make it one of the least green options for heating. You’ll pay about twice as much to heat a given space with electricity as you would spend on the natural gas needed to heat the same space. The cost of electricity is not likely to decrease sharply enough to make it cost-effective in the foreseeable future.

Aside from the cost of the equipment and the cost of operation, another consideration is safety. Very old furnaces (30+ years) normally have asbestos linings in or around the combustion chamber. These linings are considered safe as long as the asbestos doesn’t become “friable” or airborne. (Asbestos can also be found in some old ductwork.) Friable asbestos releases microscopic particles that can remain suspended in air. If asbestos particles are inhaled, they collect in the lungs and the body cannot clear them out. Long-term exposure to asbestos can lead to a particularly difficult form of lung cancer known as malignant mesothelioma.

The potential for health problems is real when the asbestos lining in a furnace deteriorates. New furnaces do not contain asbestos, so this kind of hazard would be mitigated by furnace replacement. In addition, very old furnaces are highly inefficient. By replacing the furnace, homeowners can recover the cost of the new heating equipment in just a couple of years!

An added consideration is that most high-efficiency furnaces vent directly to the outside, bypassing the chimney altogether. Exhaust gases from conventional gas furnaces and oil-burning heaters are vented up the chimney and can damage the interior of the stack over time. To repair this, the chimney may need to be rebuilt or lined, which can represent a significant expense.

In the next few weeks, I’ll look at oil-to-gas conversions, including reasons to convert, the benefits of direct venting for heating equipment, and the environmental considerations of oil heating. In the mean time, if you’d like more information about oil-to-gas conversions, or replacing old furnaces, please contact us at Boston Standard Plumbing & Heating at (617) 288-2911 for a consultation.

Lighting A Pilot Light

If your furnace or boiler has a pilot light, you’ll want to know how to relight it. Newer models usually have an electronic igniter and don’t use a pilot light, but plenty of “vintage” heating equipment is still in service. In a furnace, the pilot light and the thermocouple work together to keep the gas flowing or shut the main gas valve off if a problem occurs. If the pilot light goes out or doesn’t otherwise burn well enough to keep the thermocouple hot, the thermocouple will release and the main gas valve will close. When this happens, your furnace won’t turn on.

Downdrafts – air that is forced down the chimney from the outside by a high wind – can occasionally cause a pilot light to extinguish itself. This is normal and doesn’t indicate a problem.

Lighting a pilot light is a relatively easy task. Your furnace may even have a label that provides precise directions and diagrams for your particular model. If so, follow the directions on your furnace. If not, I’ve provided general directions for lighting a pilot light.

To light a pilot light, turn your home’s thermostat down or off. (Don’t skip this step!). Some directions tell you to turn the thermostat on and up to 75 or 80 degrees. If your thermostat is on and asking for heat, your main burners will ignite as soon as you light the pilot light. If you’ve never seen the main burner on your furnace ignite, it can be a little surprising to see that much flame! Personally, I don’t like that kind of excitement, and since the thermostat and the pilot light are independent, I see no need to get the thermostat involved at this point.

You’ll need a flame source, like a match or lighter. Pilot lights aren’t known for their convenient location. You’ll want a long match or even a butane barbecue lighter for this task because you may have to get the flame deep into the furnace to get the pilot light’s attention.

Access the pilot light on the furnace. It may be behind a little door or you might have to remove side or bottom panel on the furnace to expose the pilot light assembly. You’ll have to open the pilot’s safety valve manually, usually by pressing and holding a big red button or turning a knob to the “pilot” position and holding the knob in. (It’s usually a two- or even three-handed job!) If your pilot switch has been replaced, the button may be a different color, but it will be in a pretty visible location and it will probably be the only button around.

Light the match and put it near the pilot light. Once the pilot light ignites, you’ll have to hold the safety valve open for about a minute, while the pilot light heats the thermocouple. After a minute, let go of the button. The thermocouple should be hot enough to keep the valve open by itself. If the pilot light stays lit, button up the furnace. You’re done! Turn the thermostat up to your preferred setting and warm up.

If the pilot light will not light, stay lit or the thermocouple disengages repeatedly (you’ll hear a loud “CLICK” when the thermocouple lets go), you may have a bigger problem that requires professional intervention.

When the weather turns warm in the Spring, you can extinguish the pilot light on the furnace to save a few dollars on your gas bill each month. You won’t become wealthy by doing this, but there’s no reason to waste gas, either. If you decide to do this, be sure to turn the pilot light’s gas valve to the “off” position before you shut the system down for the summer. If you have a button rather than a knob, the valve will be a little thumb valve you can turn 90° and will be located somewhere near the pilot light. If the valve isn’t obvious, follow the gas line from the pilot light to the first valve you find, and might be located outside the furnace cabinet.

We’re always on call at Boston Standard Plumbing & Heating, so even if you just need your pilot light lit, we can help. Contact us at (617) 288-2911 and we’ll be happy to lend a hand.