If you’re thinking about investing in a new furnace or boiler, your best bet would be to simply have a heating contractor install a unit just like the one that has been keeping you warm for the last 15 or maybe 30 years. That’s not necessarily true. First off, today's furnaces and boilers must comply with efficiency and safety codes that didn't exist back then. And maybe you'd like to switch to a new heating source or a unit that delivers a different amount of heat. Whether you choose a furnace, boiler, gas fireplace or wood stove, careful shopping will help you make a decision you can live with for years to come.
 

Energy Efficiency. If, like most home owners, you want to reduce your energy costs, it is probably a good idea to check out your home for inefficiencies that will likely affect your heating bills whether or not you get new heating equipment.

Have a qualified heating contractor check your heating/cooling system at least once a year to detect cracks or leaks and make sure the unit is clean. The contractor will also check motors for any unusual noises and make necessary adjustments.

In addition, have the heating contractor examine and survey the system to be sure the ductwork is properly sized and that cold-air returns are not blocked, restricted or perhaps even missing vents. Report any complaints about uneven heat, too. If the survey detects dirt accumulations, then call in a duct cleaner.

Whatever the condition or power of the heating and cooling system, performance will be lousy if your house is poorly insulated. And by today’s standards, unless they’ve been improved recently, most older homes don’t have sufficient insulation. If necessary, have an insulation contractor evaluate your home and recommend the most cost-effective way to acceptably improve upon the insulation level.

Older windows are notorious for defeating the efforts of heating/cooling systems. Since a tremendous amount of air typically leaks like crazy through the sills and the glass itself, consider replacing older windows with new, efficient double- or triple-glazed units. Because many of them are factory-painted with long-lasting finishes, they won’t need to be repainted for a long time.

To avoid paying for energy you don’t need, check out programmable thermostats that lower temperatures and restore them when you need it. A "zone system" also can be installed, using switches, thermostats and dampers to heat and cool only the rooms you are using.

Many utilities today can help you save energy. Ask about significant rebates on high-efficiency heating/cooling systems and water heaters. But be aware that some homeowners have in effect spent the rebate to buy a higher-efficiency or higher-output unit than they needed, thus squandering the rebate and maybe not getting the fuel savings because the unit was not operating in its optimum range.

Probably between 50 percent and 70 percent of the energy used in the average home is for heating and cooling. Practically all home-comfort products sold today are more efficient than those available 10 to 20 years ago. Likewise, many gas fireplaces  are better in that regard too. If you are expecting to live in your home over the conservative 15-year lifetime of a new unit, you can easily recoup the additional cost of the most-efficient product currently available—if it is sized properly.

Working With A Professional. Because these products are so complicated, the choices so extensive and the price ranges so broad, it’s important to seek professional help in determining the best choice for your particular circumstances. This includes safety and energy-conservation considerations.

For furnaces or boilers, this help will most often come from a heating contractor who both sells and installs the equipment. In most cases they also handle air-conditioning equipment, and if they also handle boilers, they probably will also be plumbing contractors. In the case of gas fireplaces, if the store does not have certified installers on staff it should be responsible for delivering the unit and arranging for a certified installer to do the installation and hookup work for you. The safety and performance risks are too great to do otherwise. And don't forget that heating products carry a bundle of local and national codes that must be followed.

Once you are armed with information about your home, your existing heating plant, your expectations and your budget, it is time to talk to three or more local heating contractors. The more information you can provide, the more helpful the contractors can be.

Make sure you understand the type of heating plant you have—a gas or oil, ducted, circulating warm-air furnace or a gas- or oil-fired boiler that heats and circulates water through baseboard radiators or wall panels. Copy the make, model, serial number and rated Btu (British thermal units per hour) from the unit’s nameplate, and look for a log that might show installation and servicing dates. Total your annual fuel bills for the last several years, and jot down the square footage of your home. Be prepared to describe what you know about the home's insulation and the age, type and condition of the windows.

With today’s tight industry and governmental controls on efficiency standards and safety features, selecting a model among the many reputable brands available may not be your biggest concern. It’s more important to select a contractor who will do the best job of picking a model and size to best suit your needs and desires, and then do a first-class installation. Insist that they make a heat-load analysis for your house and submit bids that describe fully the proposed unit and the installation work to be done.

Be aware that the simplest installation of a replacement heating unit will be with a unit of the same type, where most everything except the unit itself is reinstalled to fit the likely different size and shape of the new one. This may include replacing the air-conditioning unit if your existing furnace has one. You may also want to get a new air-conditioning unit at the same time, which should fit exactly to the new furnace. New air conditioners are also more efficient than yesterday’s models, and the same applies if you have a boiler heating system that incorporates a water heater.

Switching Heating Systems. If you are totally renovating your home or building a new one, you can probably pick just about any kind of heating you want. But choosing a heating plant for an existing house can have limitations simply because of the significant added cost. One interesting choice for a total renovation is in-floor hydronic heat, wherein a boiler circulates heated water through pipe buried under the floor. New materials are available so that upper floors can carry piping too.

A fairly easy option is to replace a gas or oil furnace with an electric heat pump and probably use the existing ductwork. Heat pumps work like refrigerant-type central air conditioners in the summer and reverse the process in the winter to circulate heated air. Without help, they may fall short of keeping you warm when it gets really cold, but resistance heating units in the plenum can help with this. Going for about $2,700 to $4,500, home heat pumps may seem pretty pricey, but keep in mind that the cooling is included. Heat pumps are safe, quiet, clean and require little maintenance, but they lose their appeal in locales where severe cold is combined with high electric rates. Discuss this issue with a qualified local heating contractor.

A ground-source or geothermal heat pump circulates water and antifreeze through a pipe loop or coil buried deep in your yard and depends on earth temperature differential as a heat exchanger. A turnkey installation might cost $10,000 to $15,000 for the average home.

The majority of homeowners probably will stick with the type of energy source they’re already using—be it natural gas, liquid propane or fuel oil—simply because it’s available in their particular location and they're used to it. However, if you’re using liquid propane or oil and natural gas has just been piped into your neighborhood, you may want to think about switching. Natural gas will likely be less expensive, but a gas furnace will have to be converted or replaced, an oil furnace must be replaced and you’ll have to dispose of the tank as well.

Size And Efficiency. Residential furnaces and blowers are rated by heating in Btu and range from about 40,000 to around 120,000 Btu. Makers typically have several sizes within a series with the same features and quality to suit different-size homes. Federal efficiency guidelines have eliminated low-performing models. The AFUE (Annual Fuel Utilization Efficiency) must be at least 78 percent; around 80 percent is considered mid-efficiency, above 90 percent high-efficiency, and very high-efficiency units rate about 94 percent or higher. Most high-efficiency units are "condensing" systems, a design used to extract nearly all the heat out of exhaust gases. Not surprisingly, within a given Btu-capacity range, the better the efficiency, the higher the cost.

Question any bids that are based automatically on the same-size unit you already have. Your home’s condition and your heating needs have probably changed since the original unit was installed.

Shopping Tips. With today’s efficient heating systems, the exhaust gas temperature drops as the heat is wrung out, and because gas is not buoyant, this makes it difficult to vent it up a chimney without help from a fan. The problem, called backdrafting, could allow carbon monoxide into the house. Therefore, mid- and high-efficiency units use induced draft—wherein a separate fan helps force flue gases outdoors through a vent pipe.

Further enhancing safety, some furnaces use sealed combustion chambers where combustion air is drawn in and exhausted out in total isolation from inside air. You can also have an outside air inlet installed directly to the heating unit to replace air that goes out the flue.

Simply put, furnaces and boilers (and that goes for gas fireplaces and wood stoves too) must have appropriate venting for indoor air quality and safety. Regular tune-ups, cleaning and system inspections are vital if you want to keep your heating system operating at top efficiency. Schedule them with your contractor every two years for gas and annually for an oil-fired unit.

· Gas furnaces. Residential gas furnaces can cost between $1,300 and $3,500 for basic units, installed. Btu capacities can range from about 40,000 to 140,000. Because gas furnaces are the biggest sellers, high-volume manufacture and fierce competition have given rise to innovation and a wealth of attractive features. Top-of-the-line furnaces typically have sealed combustion chambers. Some have variable speed air-distribution blowers to save electricity by matching speed to need. This feature can also accommodate systems fitted for multiple-zone heating and for continuous ventilation. Many furnaces have "hot surface" or electronically fired ignition to save energy by eliminating the need for pilot lights, as well as microprocessor controls to optimize energy usage and comfort. Liquid propane furnaces have different gas orifices and controls to accommodate different gas characteristics. Many models can be ordered fitted out for one or the other type fuel.

· Gas and oil boilers. Boiler prices range from $2,200 to $3,900; the latter units may feature integrated water heating. To keep pace with demands for higher efficiencies, more boilers have electronic ignition systems, and more insulation to reduce water-tank heat loss. Very sophisticated electronic controllers on some models can be programmed to adjust the water temperature to your heating needs.

You might be interested in adding domestic hot water heating or changing the current system if you are replacing the boiler. Tankless coil-types heat domestic water passing through a coil located inside the boiler. Indirect systems involve a separate domestic hot-water storage tank, which is heated on demand by the boiler. It is integrated into some new boiler systems or can be added to some existing boilers not so equipped.

Gas Fireplaces.

Nowadays, these products are sold more for decorative use than as the primary home heat source. However, they can serve as a suitable heat source if they are properly sized and installed.

Gas fireplaces are mainly marketed by specialty hearth stores. A few heating and air-conditioner contractors sell them along with furnaces and boiler products. You will also find them in building-supply stores, home centers and perhaps farm stores. You will note that some fireplaces have "ceramic" glass viewing windows that withstand thermal shock to about 1450° F. Regular tempered glass tolerates 450° F.

For safety and satisfaction, stick with dealers who know the applicable codes in your area, and are qualified to recommend the best product and sizes for your specific needs, and then deliver them and make the necessary hookups and adjustments, as well as provide service. To ensure health and safety, pay attention to installation clearances, proper venting and gas hookups.

· Gas fireplaces. Because of air-pollution concerns and bans on installing wood-burning heating appliances in some areas of the country, today’s gas fireplaces offer some great alternatives. They are clean, fuel-efficient and require minimal effort to build a beautiful fire. Arguably, the most attractive buys in gas-fireplace products these days have direct venting. Along with having a sealed firebox, this means combustion air is drawn into the unit and exhaust gases are expelled outside via a coaxial flue installed in the house wall behind the fireplace—or optionally through a coax chimney pipe in some cases. The efficiency and safety are very impressive. Jerry Husby, president of Ralston Creek Co., with specialty hearth stores in Iowa City and Cedar Rapids, Iowa , sums it up this way. "Direct-vent gas fireplaces are the best thing that’s ever happened in the hearth industry. Just be sure you get expert advice and installation."

Gas fireplaces come in many varieties. If you simply want a nice flame, you can have a gas log installed in a wood-burning fireplace for about $550 to $900, somewhat less if your unit has a gas hookup already installed. Or for serious heat, consider a gas, direct-vent fireplace insert that fits into the fireplace opening for perhaps $1,200 to $2,800.

The most versatile direct-vent, sealed-combustion can be set with minimal preparation on floors and within an inch or so against walls and other surfaces and in wall recesses. They can be framed or boxed in and given a variety of mantle and hearth treatments.

Make sure the unit is heater-rated, which indicates the maker had the unit tested to certify compliance with applicable American Gas Association (AGA) standards for gas furnaces and boilers.

Vent-free gas fireplaces and other heating appliances are also available that do not require venting because of incorporated oxygen-depletion sensors that shut down the units when the room oxygen level falls to 18 percent. Not requiring vents, they are less expensive, but they may not be approved at this time for use in all areas. Check with your local dealer.