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What is a Good Furnace AFUE Rating for the San Marcos Area?

February 21, 2019

cost to replace furnace in san marcos

First, a quick refresher: AFUE stands for Annual Fuel Utilization Efficiency. It is a measurement expressed as a percentage that shows the energy efficiency of a furnace.

The higher the AFUE percentage, the more efficient the furnace—and the lower your energy bills.

So what AFUE rating do we recommend?

We typically recommend any AFUE above 80%. We know that’s an imprecise recommendation, but without looking at your current HVAC system and home’s build, we can’t accurately give you a specific AFUE recommendation for your new furnace (more on that later).

In this article, we’ll explain the following information:

  • Why we recommend any furnace above 80% AFUE
  • Why you need a professional to provide an AFUE recommendation

Want an accurate AFUE recommendation for your new furnace?

Why we recommend any furnace above 80% AFUE

Per federal regulations, new furnaces must start at 80% AFUE. So, you the minimum AFUE rating you’ll likely find on the market is 80%.

That said, as you’re looking around, you’ll see 2 categories of furnaces:

  • 80% to 89% AFUE – Non-condensing units
  • 90% to 98.5% AFUE – Condensing, high-efficiency gas units

While both categories of AFUE ratings are considered energy-efficient, 90%+ furnaces offer the highest potential for energy savings.

However, while 90%+ AFUE furnaces are more energy efficient, they’re also significantly more expensive to install.

So if you’re considering a high-efficiency furnace, you should make sure your long-term savings (via monthly energy bill savings) outweigh the higher installation cost of the unit.

But that’s where you’ll need help from a pro...

Why you need a professional to give an AFUE recommendation

The actual long-term energy savings you’ll get depends on several complicated factors, including:

  1. The condition of your ductwork and your home’s insulation levels: AFUE does not factor in the possibility of leaky ducts and poor insulation. The leakier your ducts are, and the weaker your home’s insulation, the more money you waste each month—regardless of how high the AFUE rating is.
  2. The fuel source you choose: Since gas is a cheaper fuel source than electricity here in San Marcos, we usually recommend going with a gas furnace over an electric one. That said, if you don’t have access to natural gas, the cost to add a gas line might make the cost to install a gas furnace too costly. In that case, you’ll want to stick with an electric unit. One of our techs can recommend help you choose the fuel source that best fits your needs and budget.
  3. The technology in the furnace: Monthly energy savings also depends on the technology of the furnace, not just its AFUE rating. Furnaces with more advanced technology (variable-speed, modulating furnaces) will be more energy-efficient than furnaces with basic technology (single-stage/single-speed furnaces). This means, for example, that an 80% AFUE modulating furnace will probably save more than a 95% AFUE single-stage furnace.  

Because these factors can be difficult to calculate, it’s best to have a professional inspect your home and crunch these numbers. That way, they can give you an accurate AFUE recommendation for your new furnace.

Want an AFUE rating recommendation for your new furnace?

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