If you’re lucky enough to have a working fireplace, or you’re hoping to one day have one, you know that they’re a great addition to a home. Fireplaces add such great ambience to a house or apartment.

There’s just something magical about a natural fire on a cold winter evening. Fireplaces have brought people together for centuries, and they continue to be the social center of many modern homes.

The effective use and management of a fireplace is the most important factor in keeping you and your house safe while you enjoy sitting in front of the flames with a book or nice glass of wine.

It will help keep fires alive and use the fireplace to heat your home efficiently. Misuse can cause fire hazards and fill your house will billows of smoke.

Here are some tips on how chimney flue size and proper flue operation can help with a great fire.

The Chimney Flue size and How Draft Works

chimney flue size

Fireplaces can look like very simple contraptions to the layperson, but they’re actually quite an engineering feat. They’ve developed over centuries of use and continue to be refined and modernized.

Drafts are one of the most important aspects of chimney function. It’s the force that pushes air up and out of your chimney. It keeps smoke from feeding into your bedroom, living room, basement, or wherever the fireplace is located.

Draft operates on the principle that hot air rises. Hot air being shed off by the fire is pushed up through an open flue into the chimney and outside. The draft also pulls on cooler air inside the house to continue to feed the flames.

Getting a good draft on a fire will make sure your house stays relatively smoke free. It will also use up cold air in the house and warm things up quicker.

The wrong chimney flue size is one of the main reasons for a poor draft. If your fireplace just can’t seem to get right, and clouds of smoke push back into your house, check the flue.

A flue that is not big enough doesn’t allow enough air flow. Not enough hot air is pushed upwards into the chimney and, as a result, smoke spills over into the house.

When a flue is too big, the chimney can be too cold. Cold chimneys make keeping a fire lit more difficult. They also lead to condensation and possible mold inside the chimney brickwork.

They key to making and keeping a great draft in your fireplace is making sure the proper sized flue is installed.

How Big Should Your Flue Be?

There can be some specific fireplaces that are exceptions to general rules that make citing an exact flue size difficult. However, generally speaking, a rectangular chimney flue size should be at least one-eight of the fireplace’s opening.

If the flue is circular, then it should be at least one-tenth the size of the fireplace opening. Flues should also mirror the size of a chimney. If a chimney’s diameter is six inches, then the flue should also measure six inches.

Again, if the flue is too big, though, it can mean the fire cools too quickly. This can make keeping a fire lit and heat generation more difficult. It can also result in excessive buildup of creosote inside the chimney.

Homeowners and fireplace operators need to remember that taller chimneys often keep a better draft than shorter chimneys. Typically, a chimney should be at least 15 feet tall.

The height of a fireplace is measured from the floor of the fireplace to the top of the flue.

The type of material used to build your chimney will also impact flue size. Metal or pre-fab chimneys use a different venting system than masonry fireplaces. Modern homebuilders favor metal and pre-fab chimneys because they’re fast and less expensive than traditional brick chimneys.

Installation and Replacement

Measuring out and installing a chimney flue can be quite a challenge. For DIYers not totally confident in their abilities, it’s a good idea to ask an expert for recommendations on flue size.

Installing the wrong flue size is not a mistake you want to make on your home. Replacement can be costly and time-consuming. Luckily, a lot of chimney experts or masonry workers will be happy to give advice on how large or small your flue should be.

Make sure you follow general guidelines accounting for any unique build aspects involved with your fireplace and chimney.

Professionals usually recommend installing a stainless-steel flue lining. It’s wise to opt for one as large as the fireplace opening or stove outlet. Keeping the flue large enough will make keeping good draft easier.

DIYers should be aware if their homeowner’s insurance policy dictates whether a professional is required to install and maintain a fireplace and chimney.

If it does, and homeowners still attempt to install or repair a flue themselves, any fire damage that occurs in the home tied to the fireplace could be denied coverage.

Get Your Flue and Fireplace Checked

Fireplaces are such a wonderful addition to homes that they’re still a highly-sought after amenity. Home buyers love to see cozy fireplaces in listings.

They dream about they’ll be sitting in front of the fire on a cold night reading a book or playing board games with the family. Despite how often they get used, fireplaces still add value to homes and are a great feature.

If you’re going to be using your fireplace, take the time to learn how to properly work a fire. Think about getting your fireplace inspected by a chimney expert to make sure it’s structurally sound and capable of generating a good draft.

The last thing you want is to try your new fireplace out and have smoke fill the room. Bad fire experiences sour the fireplace for many homeowners. As a result, they sit idle when a few small adjustments could make then work perfectly.

Don’t let an improper chimney flue size or bad draft keep you from feeling the warmth and other benefits of a beautiful fireplace.