Tuckers Air Conditioning, Heating & Plumbing Blog

Heating Replacement Tip: Signs of an Undersized Furnace

If you’re purchasing a new furnace for your Rockville home, you want to avoid buying one that is undersized for your particular space. To do that, here are some common signs that the furnace isn’t powerful enough for the heating needs of your home. These signs might appear for an older furnace as well, especially as it ages and loses its ability to provide adequate heat for your home.

Maintaining Temperature

The most common (and in many cases only) sign that your furnace is undersized is that the device simply doesn’t maintain the temperature in your home properly. This means that when turned on to full and left for a few hours, your furnace doesn’t heat your home to the thermostat setting.

This can be due to an improper load calculation or a load calculation that wasn’t taken at all. The perfectly sized furnace will heat your home evenly on the coldest day your area is likely to have. So, undersizing should be pretty evident – if it doesn’t heat your home evenly and it’s not exceptionally cold outside, you might not have enough BTUs under the hood.

How to Fix the Problem

The problem is one that varies depending on the severity of the undersizing. Modern furnaces are often available with two stages, meaning they can operate at both a low BTU rating (often around 40K or so) and a higher BTU rating (70K or higher). This is the perfect solution for homeowners worried about undersizing because it ensures that your home always has enough heat in reserve should the weather get exceptionally cold.

For example, most furnaces are sized for extremely low temperatures, but if the temperature jumps up to 50 degrees F outside, your furnace is now oversized for that weather. A two stage furnace offers solutions for both common conditions and extreme conditions and will resolve most of the concern you have about undersizing and not having enough heat to offset outdoor temperatures.