Single-Stage vs Variable Speed Models

What are Single Stage and Variable Speed Models

Single stage gas furnaces operate at the same capacity the whole time (100%). They are more affordable and suitable for smaller homes in warmer climates. They have a lower AFUE rating of around 80% percent, converting 80% of their fuel into heat while losing 20% through exhaust. While variable speed models can adjust the capacity (10% - 100%) at which they operate and are much more efficient. They are more expensive than single-stage units but help you save money in the long run. Since they can change their capacity rate they use less electricity and natural gas, reducing fuel costs. These systems have a high AFUE rating of around 96%, only losing 4% through exhaust! They do cost $1,000 to $2,000 more than single-stage models but are usually paid for within just 5 - 7 years!

Cost Savings Using Variable Speed Models With High AFUE Rating

*If you pay around $125 per month for heat and paid $2,000 more for a 96% AFUE unit, you would pay off the cost in about 8 years.

When to buy a High 96%+ AFUE Unit

If you live in a moderate to colder climate and pay at least $100 per month for heating, you should probably upgrade to the higher 96% AFUE unit. It would only take you 5 - 8 years to pay off the cost.

When to not buy a high 96%+ AFUE Unit?

If you live in a warmer climate, live in a smaller home, and pay less than $75 per month for heating, you should probably buy a single-stage unit. The savings from the high AFUE unit would only be minimal and take almost the whole lifespan of the furnace to pay off.