Should You Consider A Modulating Furnace?

There's more to buying a new furnace than just deciding between standard and high-efficiency models. Like any technology, residential furnaces are continually changing and improving.  You can choose between a wide range of options, including high-end modulating furnaces. If you haven't heard of this type of furnace before, then it may be worth considering for your next upgrade.

What Is a Modulating Furnace?

Most HVAC systems use a relatively simple operation method: they continuously output air at a single temperature until your home reaches your desired setpoint. The air from your vents will never be warmer or colder, no matter where you set your thermostat. Two-stage furnaces can vary their blower speed, but their flame intensity will always remain the same.

Single-stage and two-stage furnaces are relatively cheap and reliable, but they are not without downsides. Since they can only control the temperature by turning on or off (or switching between high and low blower speeds), they can have trouble maintaining one setpoint. Allowing your home's temperature to fall several degrees before turning back on can also waste energy.

Modulating furnaces attempt to address these issues by providing the furnace with finer-grained control over its output. Instead of operating at one temperature, they can vary their flame intensity and fan speed. This design allows the modulating furnace to run non-stop instead of in cycles, changing its heat output along the way to maintain a temperature relatively close to your thermostat setpoint.

Is a Modulating Furnace Right For You?

Modulating furnaces are expensive and may cost several times the price of even high-end two-stage units. They justify their costs by providing greater efficiency and consistent interior temperatures, but that doesn't mean that they're a good fit for all situations. If you're considering upgrading or replacing your existing furnace, then you'll want to weigh your options carefully.

First, consider other issues in your home that may affect heating performance and efficiency. Do you have old, leaky air ducts? Does your home suffer from drafts around windows and doors or heat loss due to poor insulation? Modulating furnaces are less beneficial if your home's envelope isn't well sealed, so they may be unable to justify their extra cost in these cases.

You'll also want to consider how satisfied you are currently with your home's heating situation. If you find that your existing furnace already keeps you warm and comfortable, then a modulating furnace may be unnecessary. Upgrading to a single- or two-stage high-efficiency model may be a cheaper option that will save you some money on your utility bills.

Ultimately, modulating furnaces are a worthwhile upgrade, but you will need to decide if their high cost fits within your budgets and needs. Discussing your upgrade options with an experienced contractor can help you to determine if it's the right time for you to take this large step.