HVAC Blog

Replacing the old furnace in your central heating system with a new more efficient model can offset volatile energy prices. Also, today’s furnaces pollute less and boost comfort by producing heat more steadily than older furnaces.  Gas is the most common heating fuel and here we will focus on gas furnaces.

Over the next several posts, we will cover the most important parts in the process of selecting your gas furnace….

1. Size matters – The furnace’s specifications should meet your needs.
2. Efficiency also matters – The efficiency of gas furnaces is reflected in its AFUE
3. Repair or replace – Depends on what’s wrong and the age of your system
4. Most and least reliable – Usually when do systems fail? When they are most needed
5. Features – Each brand of furnace offers a similar array of key features
6. How to choose your contractor? Key qualifications to look for.

The furnace’s specifications should fit your needs. Installing a new furnace that’s too small won’t keep your house comfortable during extremely cold weather.

To offset that, the furnaces in most homes are larger than necessary. Initial cost is only one of the drawbacks of that strategy. A furnace that is too large will cycle on and off more frequently. That puts more wear on its components, wastes energy, and might cause the temperature to vary to uncomfortable levels. Also, a larger replacement furnace might require larger ducts. Without the right size ducts, airflow can be noisy.

To be sure of correct sizing and a proper installation, choose a licensed, reputable contractor who will take the time to calculate your heating needs. Such calculations take into account the climate and the size, design and construction of your house.

Gas is currently the most common heating fuel and most new central-heating systems use gas. How efficiently a furnace converts gas into heating energy is reflected in its annual fuel-utilization-efficiency (AFUE) rating, which is measured as a percentage. The higher the number, the more heat the furnace can produce from each therm of gas.

Furnaces have become more energy-efficient over the years. A gas furnace made in the early 1970’s typically has an AFUE of about 65 percent. The lowest efficiency allowed by law for new gas furnaces is 78 percent, and some new models achieve 97 percent.

The price of a new furnace generally rises in step with its fuel efficiency but you can often recoup that additional cost through lower fuel bills over the life of the furnace. How quickly you recover the investment depends on more than just AFUE. The climate where you live, how well your home is insulated, and your local gas and electricity rates also affect payback times.

A Woods consultant can present several models in a range of efficiencies and help you calculate the annual estimated operating cost of each model you’re considering.