Most residential central heating systems are fueled by gas, oil, or electricity. In hot climates, this arrangement is replaced by central air conditioning. And some folks in places where winters are cold and summers are hot have both.

No matter where you live, keeping warm when it’s cold and cool when it’s hot is a high priority for most of us. It’s important to take care of the equipment that makes it happen.

Because there are hundreds of brands and models of furnaces, boilers, and other heating components, this chapter will give you basic information that anyone with a heating or cooling system should know. For specifics, you should check with your system service company and/or your use and care manual.

Let me begin with one basic piece of advice. The best way to keep your heating and cooling equipment working well is to have it checked annually by a service professional. For heating systems, that means a fall checkup before the peak heating season begins. For central air, spring is the season for this work.

Nothing is more frustrating than having equipment fail when you need it. Anyone who’s had the experience knows that a furnace man is hard to find on the first very cold day of heating season. Likewise, the air conditioning specialist disappears during a heat wave; the demand for his services may put your repair at the back of the line.

If you’ve never had your heating system serviced before, it’s worth doing for two reasons:

You should take notes on the operation of your system for your home workbook:

More than half the households in the United States are heated with gas, so we’ll address this furnace type first.

While gas furnaces have few moving parts, they should be checked annually. Most companies that provide your gas supply will also, for a monthly fee, offer a contract to service your furnace.

Among the things a service pro will inspect:

Gas furnaces do not usually need annual cleaning (every couple of years is fine), and this can be done via the gas company service people (usually this requires an additional fee), or a certified heating/cooling specialist.

Every 5 years or so, the ductwork should be cleaned. Over time, these heat passageways become collection centers for dust, and sometimes mold or mildew, if your home has a humidity problem. All of these pollutants can be bad for your and your family. This is also a job for a specialist.

Between the annual checkups, your only important task is to change or clean your furnace filter regularly. See Chapter 14 to learn how it’s done.

Only about 7 percent of the country heats with oil, but oil heating systems are more complex than gas furnaces or electric units. If you heat with oil, an annual maintenance appointment should be a given.

When the pro performs the annual tune up for your furnace, he’ll do a lot of things:

Some service pros will also balance a heating system (steam), or bleed radiators (hot water). Actually, you can do the bleeding yourself (see the section later in this chapter).

Like many households in the Northeast, we have an old, oil-fired hot water boiler. It’s been running for quite a long time, because it is serviced and cleaned every year. We repair and replace anything that’s needed to keep it running. In fact, we’ve replaced so many of its components my repair guy jokes that, at this point, we’ve got all-new equipment!

We’ve also got a service contract, an agreement with our oil delivery/service company, that has probably saved us thousands of dollars over the 25 years we’ve lived in our house.

Our service contract is like an insurance policy. It pays the company a certain amount of money to cover the costs of an annual cleaning. It also covers any emergency service calls that might be made in the course of that year, and it provides for replacement of certain parts, which can be a big savings if you should need them. It’s not very costly.

On the other hand, without a contract, midnight runs by oil furnace repairmen, purchased à la carte, can be very expensive. If you have oil heat, a relationship and a contract with a full-service company that delivers oil and does repairs is well worth the price.

As the cost of electricity rises, electric heat becomes less and less of a bargain, especially in parts of the country with a long heating season. Many of the systems installed in the 1960s and 70s, when kilowatt hours (kWh) were cheap, have become very expensive to run.

In places where freezing temperatures are rare, a backup system of baseboard heaters, or a pump that can be controlled to provide both heating and cooling, makes sense. But if you live in a frigid area and have electric heat, I have a word for you: sweaters. Wearing them inside will help keep the bill down.

Baseboard electric heaters have their own heating elements that connect directly to your home’s wiring system. While using them constantly is very expensive, most of these systems have thermostats in each room; you can turn off the heat in unused spaces.

Because these baseboard heaters collect dust, debris, and animal hair, they can smell very funky when you first turn them on in cold weather. Be sure to dust and vacuum these units before using them, to avoid the smell and to prevent a fire hazard.

Another type of electric heat is generated by a furnace that will warm air and, via a mechanical blower, will push the air through a system of ducts and registers, or to baseboards. While the system is configured like a gas furnace—with electric-powered heating elements instead of the gas flame—heating air this way is inefficient and very costly.

No combustion takes place in this type of furnace, so there’s no flue. And only the blower unit of an electric furnace has moving parts, so servicing of the equipment is fairly easy. Filter and humidifier (if there is one), need to be maintained according to manufacturers’ directions.

If you call for heat by turning up the thermostat—and nothing happens—don’t panic. Here are the steps you can try for each type of furnace before calling your professional heating company for service. If you have a good service company, they may walk you through these steps, anyway, before sending someone out.

Before picking up the phone to call your repair service, try these fixes in this sequence:

If you have an older, standing pilot furnace (you should know this before you start playing around with it), if the pilot has gone out the burner will not light. Do not light the pilot yourself if you are not sure how your own system works! Put on a sweater, call for service, and wait for the pro to arrive.

In general, to light the pilot on a gas furnace, you will find instructions near the pilot control knob on the furnace. You’ll need a long match or a long, tubular grill lighter to do the lighting.

Electric baseboard heat will not work in a power outage. If you have baseboard units with heating elements and they’re not getting warm, and your lights are on, try these actions:

At the main panel if the breaker that controls the baseboard heater(s) is flipped to off, turn it back on. If you have a fuse panel and the fuse is blown, replace the fuse with a fresh, identically sized fuse. Then turn up the thermostat that controls the baseboard heat. If it still doesn’t work because the breaker has flipped or the fuse has blown again, you need to call an electrician.

If you have an electric furnace, you can try Steps 1 and 2 above, first. Also make sure, if your thermostat controls both heating and cooling, that the selector switch is on heat mode.

Call for service if the furnace fails to start.

First, check that the emergency switch has not been flipped off. Also check the electrical panel to see whether or not the breaker or fuse that controls the heating system has flipped off or blown. Flip the switch to on, or change the blown fuse.

You can turn on the furnace if you know the location of the restart button. This is a red button located in one of two places:

Press this control only once. Pressing it repeatedly is dangerous. If the system doesn’t fire up immediately, call for service.

I hope you understand from this chapter that the maintenance that keeps your heating equipment in top running shape is best done by a trained professional. However, that doesn’t mean that there’s nothing you can do. In fact, there are a few important things that you should do.

Any forced air heating system is equipped with a filter, usually located next to the blower on your equipment. Have your service pro show you the filter, or refer to your equipment manual. Disposable filters should be replaced, and the old ones discarded, every month during heating season.

If you have an ionizing filter—an air-cleaning device that gives tiny particles a charge that makes them stick to the surface of the filter until they are cleaned off—it is not disposable, but needs to be cleaned regularly. For information about furnace filters, check out Chapter 14.

Warm air (and cool air, if you have a central air system that uses the same ducts) comes into your living spaces through vents and/or registers. These need to be clean and unobstructed by furnishings and drapes.

Before any heating or cooling season, make sure that no furnishings block the vents or registers. Vacuum any dust, debris, or pet hair that accumulates on these outlets; remember the forced hot or cold air will blow this stuff around your house if you don’t remove it!

Every couple of years you should have your heating/cooling ducts professionally cleaned. This process not only vacuum-cleans these passageways, but also removes any pollutants such as mold or mildew.

Use the brush or the crevice tool of your vacuum cleaner to keep your radiators and baseboard heaters clean. Be careful not to bend or damage the little aluminum fins on modern baseboard units. And don’t use the tops of radiators for storage! Let the heat flow.

Hot water heating systems often have radiators; ours are old, heavy cast iron. When these units are partially filled with air, the radiators will not completely fill with water, creating cold spots. Completely cold radiators are full of air.

To fill the system uniformly, you need to bleed each radiator, usually starting at the radiator farthest from the boiler on the supply loop of your system. It sounds gruesome, but it’s really easy, and painless to all (if you take care not to scald yourself with the very hot water from the radiator).

The bleed valve on each radiator may be operated by a standard screwdriver tip, a key (you can trace the shape of your valve and bring it to the hardware to get a replacement key—these tend to disappear), or, if you’re lucky (we are), a little knob at the end of the valve.

You’ll need the following:

These systems are uncommon, but they’re out there, especially in houses built between about 1920 and 1940. While there are some gas-fired steam systems, most are powered by an oil burner. Like other heating plants, steam systems need an annual tune-up. To keep the steam flowing into every radiator, the system needs to be balanced, and every radiator must have a working vent; these cost around $20 each. You’ll recognize the steam vent because it will probably whistle a little happy tune when the steam escapes! Most vents look like a larger version of a metal pen cap.

Make sure your service pro shows you all the fine points of steam heat. This will include how to flush the sediment from your system so that its safety mechanism, which shuts off the boiler should the water level get too low, will operate properly. Usually this feature needs regular (weekly, during heat season) flushing. But most steam-heat homeowners love the incredibly fast, efficient heat provided by their system.

Few things will make your family as grumpy as being without hot water for a shower when they want it. Water heaters, which are powered by gas in about half the homes in the United States, and by electricity in the other half, are hardworking members of your heating/cooling equipment brigade.

Most water heaters will last about ten years, but you can help prolong their life by knowing a little more about them.

A gas water heater differs from an electric model (shown in the following illustration) because it has a vent pipe (at the top of the tank), and a gas supply pipe with a supply valve (stop).

Whether your water is heated by gas-fired or electric heating elements, both types of water heaters have certain parts in common, and a couple of differences.

A gas unit must be vented, so it will have a vent pipe, usually located at the top of the heater. The pipe vents into a chimney, or (with more recent models) through the wall. An electric model has no vent.

The gas unit also has a combustion chamber inside the bottom of the unit; electric water heaters usually have heating elements inside the top and bottom of the tank.

Warm water is able to dissolve minerals that are not soluble in cold water. For this reason, the hot water in the tank is corrosive (a good reason not to drink hot water from the tap). Inside both the electric and the gas water tanks are rods, called sacrificial anodes, that act like mineral magnets. They will corrode so that the mineralized water will not go to work corroding the tank and shortening its life. Some homeowners will have the anodes replaced after a few years to lengthen the life of the water heater.

Other parts shared by gas and electric models include the drain valve. This is used to drain the water in the tank. Because the tank collects sediment from the water at its base, it’s a good idea to drain the tank every couple of years (see the instructions later in this chapter).

You’ll also want to pay attention to the pressure relief valve (see the previous illustration). This valve will automatically discharge water from the tank should pressure build up inside from an overheating element. These valves go bad on occasion and you can replace yours with an exact duplicate part, as described later in this chapter.

Once a year, you should make sure this valve is working the way it’s supposed to. Unless you have a floor drain close to the water heater, you’ll need a sturdy bucket (remember, the water inside the tank is hot; a cheap plastic bucket might soften from the heat). Position the bucket beneath the overflow pipe that is connected to the pressure relief valve.

Lift the handle on top of the valve; the overflow pipe below the valve should expel hot water. If water doesn’t come out, the valve is not working. Replace it at once. (You should also replace this part if it is leaking.)

You will need an exact replacement valve and overflow pipe. If you have the use and care manual for your water heater, you can find the part number in the manual. Or call the manufacturer with the model number of your heater (find this info on the tank); they may be able to give you the number, and even sell you the part!

If the pilot for your gas water heater does not relight automatically with a restart device after the gas has been turned off, be sure that you know how to relight the pilot before you try replacing the pressure valve or draining the water heater (see next section). Do not do these repairs if you are unfamiliar with the gas pilot!

You’ll need the following:

You’ll need a sturdy bucket (water may be hot!) or a hose that you can thread onto the drain valve and discharge in a floor drain, sump hole, or outside.

Ah! The beauty of a central air conditioning system is something I’ll never experience in my two old homes. The cost of installing the ductwork in either house is prohibitive. Besides, our home on the Maine coast needs air conditioning only about three days a year.

Anyway, most central air systems are best served by a maintenance and tune-up appointment with an air conditioning service company. Do this every year, before cooling season.

Basically, there are four main parts to any air conditioner (even the little room air conditioners that are mounted in a window opening):

During your first service appointment, have the pro show you all the parts of the system, its controls, and how to start and stop your unit. Have him or her also go over any troubleshooting you can do yourself to diagnose problems.

Keep all this information in your home workbook.