Encinitas Air Conditioning & Heating Knowledebase > Furnaces: What To Look For

Here are some features and considerations experts say to think about when choosing a gas or oil furnace, assuming that the contractor has determined the correct size for your house.

Super High Efficiency or 80%? If you live in an area with harsh winters, you should recoup the additional expense of super-high-efficiency (90% +) furnaces over the unit's lifetime. However, if your winters are more temperate, you may be better off with an 80% model. If you're unsure, have your contractor calculate fuel costs for both kinds of furnace, using your current bills; then you can tell if future fuel savings justify the additional $1,000 or more for a 90% furnace.
Repair or Replace? Most experts agree that it's generally more cost effective to repair your existing furnace than to replace it, but if the heat exchanger or control module gives out, you should look at a new unit. This is especially true if your furnace is more than 15 to 20 years old. Proper maintenance, such as cleaning warm-air registers and baseboards and getting your system tuned up periodically, will save money in the long run.
Multi-stage burners and variable-speed blowers are among the best features of this generation's furnaces. During milder weather, the furnace runs at a slower speed with less heat output, and then kicks into high gear when the temperature drops. This is more energy efficient and saves on wear and tear, since the furnace isn't always cycling on and off. They are also quieter, since they're not always running on high.
Think about your air conditioner. If you plan to install or replace central air within the next couple of years, be sure to tell your contractor. He'll be able to recommend a furnace that's compatible with a future air conditioner. In some cases, you might want to put in air conditioning simultaneously with a furnace, since installation costs will be cheaper and you may qualify for a longer warranty period than if you did both projects separately.
A digital thermostat can cut heating bills another 10% by maintaining more accurate temperature control. Programmable thermostats can keep the house at a lower temperature when you're not home or at night. These are also easy to install yourself.
Noise can be a problem. If this concerns you, ask prospective contractors for the decibel ratings of the units they are proposing.

Experts stress the importance of taking your time to find a good HVAC professional. The best way to start is to ask friends and neighbors for references. Contractors should be licensed and have appropriate insurance, liability and workman's comp paperwork. You will need a permit before work is started, and you should ask your contractor to procure this for you so that the work can be checked by a local government inspector.

Even if you do everything right, editors at Consumer Reports magazine say that in recent years, about one-sixth of furnaces installed over an eight-year period ended up needing repairs.