Downflow Gas Furnace Tips

If you live in an area that enjoys a good, old fashioned, freezing-cold winter, you know about all the great wintertime activities: ice skating, hockey, ice fishing, skiing, and more. But there's one other thing you know as well – the need for a nice warm home. And that's where the downflow gas furnace comes to the rescue!

Types of Gas Furnaces

Generally speaking, there are three usual types of gas air furnaces. The difference between them is inferred from the name. The name refers to the airflow direction as it travels through the furnace past the heat exchanger. The first is the horizontal gas furnace.

As the name implies it's used in a horizontal position. When might this type of unit be used? Usually when installed in a crawl space and the vertical spacing is limited.

The second type is called an upflow gas furnace. In this case, the airflow is from bottom to top and this has historically been the most common furnace for heating the home.

Finally we have the downflow gas furnace. The air flows from the top of the unit to the bottom. Then the heated air flows from the bottom of the furnace through slab-mounted ducts and distributed through the home.

How Does a Downflow Gas Furnace Work?

In a downflow gas furnace, natural gas is routed to the combustion chamber where it is combined with air. This mixture is then ignited using a pilot light. The resulting flame is utilized to heat the unit's heat exchanger.

The heat exchanger is composed of metal tubing. There are hot gases in the exchanger and the air to be heated passes over the hot surface of the exchanger. This air absorbs the heat emitted by the exchanger.

Before the air enters the unit to be heated it passes through a filter. This keeps the inside of the furnace uncontaminated. There are two types of filters available: disposable filters and washable filters. The disposable filters are easier to use, obviously, but washable filters are more effective.

The temperature of the home's or room's living space is regulated by the thermostat which the homeowner sets to the desired temperature. When the ambient air temperature falls below a specified limit, a gas valve feeding the furnace opens and combustion begins. When the desired temperature is reached, the gas is shut off.

Dangers of Gas Furnaces

When combustion occurs, vent gasses are produced in the form of carbon monoxide. Vent gasses are deadly to humans and their pets and must be vented to the outside of the home.

There are newer units on the market that are called ventless furnaces. They are rated to produce very little carbon monoxide due to being so efficient. At least, the amount produced is deemed to have a negligent effect on health.
Ventless units are equipped with a sensor switch which detects the level of vent gas in the home and is designed to shut down the unit if a minimal percentage is detected.

Whichever type of gas furnace is used, it is very important to have the system tested on an annual basis to ensure that it is safe and falls below an acceptable vent gas level.

Is a downflow gas furnace right for your home? Yes, if your ductwork is configured properly. The newer units have a very small footprint and take up very little space. An extra bonus is the efficiency of these heaters, especially the ventless variety.