Air conditioners don’t last forever. Neither do furnaces, but should you replace your furnace at the same time you replace your air conditioner – even if the furnace served you perfectly well during the previous winter?

As with most things HVAC-related, it depends.

All sorts of factors can impact your decision to replace a furnace (or not) whenever you replace your air conditioner. Let’s take a look at the most important ones.

How old is your furnace?

Age matters. If your furnace is over 12 years old, you’ll probably be replacing it in a few years no matter what. When that’s the case – and you’re already committed to replacing your air conditioner – it might be a good idea to replace your furnace at the same time. Here’s why:

  • You’ll save money on labor. If you’re going to replace the furnace in the next few years, you may as well save on labor by having the AC and furnace installed by the same techs during the same visit.
  • You can have total confidence in your furnace when winter rolls around. If you’re replacing an AC during the summer, you already know how miserable it can be not to have cool air when you need it. A furnace that quits in the dead of winter can be just as unpleasant.

Ok, but what your furnace is, say… 8 to 10 years old? It’s not an old furnace. It’s just, well, old-ish. Should you replace it with your AC?

This one’s a tougher call. You certainly can replace the furnace if you’re worried about its operational integrity, but most systems under 12 years old have a few more seasons left in them. More often than not, you can keep an old-ish furnace when you get your new air conditioner.

What kind of air conditioner are you getting?

Many people around Atlanta are replacing their old AC units with variable speed or two-speed air conditioning systems. These air conditioners cool your home more efficiently and do a better job keeping your indoor air dry.

If you choose one of these units for your next AC, you’ll probably need to replace your furnace as well – even if it’s a new furnace. The reason? Standard, single-stage furnaces are not compatible with variable-speed and two-speed air conditioners.

Remember, your furnace fan plays an important role in moving cool air through your home. The furnace itself may not be on, but the blower fan interfaces with the air conditioning system. To work with a variable-speed air conditioner, that fan needs the ability to modulate its speed. Just as the AC ramps up and ramps down to deliver the right amount of cooling, the fan has to ramp up and down to deliver the right amount of air to your home.

Standard furnaces with standard blowers can’t do that. Variable speed models can.

So, if you’re getting anything besides a standard AC and you currently have a standard furnace, the answer is yes. You will have to replace your furnace with your air conditioner.

If you recently replaced your furnace and don’t want to replace it again…

Your best bet is to stick with a standard, single-speed air conditioner. You can get one that works with your current furnace, so you won’t have to replace a piece of equipment that’s practically new anyway.

Whenever we replace your air conditioner, we’ll work with you to find a way to avoid replacing your furnace. The only time you have to replace it is when you’re getting a variable-speed or two-speed AC. Even if your furnace is really old, you don’t necessarily have to replace it. It’s just a good idea because proactive replacement can help you save on labor costs.

Regardless of what you end up replacing, remember to insist on the professional, fully audited installation of right-sized HVAC equipment. Installation quality, after all, matters just as much as equipment quality.

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