Gas Fireplace Buying Guide

What is a BTU?

Before we get too far into the thick of this section, I need to let you know about British Thermal Units (BTUs). This is an international energy measurement, not just for the Britons. 

Basically, a BTU is the amount of heat needed to raise one pound of water 1 degree F. 

Sounds like an odd requirement, but knowing the amount of heat and energy is necessary to keep your home comfortable. 

The easiest way to figure out the BTUs needed is to take a look at the square footage of the space you want to heat. In warmer climates multiply this number by 10-15. In moderate climates multiply it by 20-30. In colder climates multiply by 30-40. 

For example, if you’re trying to heat 1000 square feet in a cold climate, you’re looking at 30,000 to 40,000 BTUs to warm the air in your home. 

But to help you out, we’ve also put together this chart:

BTUs for 8ft Ceiling

BTUs for 10ft Ceiling

These are basic estimates and the actual BTUs you’ll need depend on several other factors: 

• Number of windows
• The climate
• Age of the building
• Orientation to the south
• Type of and amount of insulation
• Construction techniques
• And more

When you are calculating the BTUs you’ll need for your whole house, you need to include the worst-case scenario. Which means that you should account for the coldest that it will get. 

For example, maybe the coldest it will ever get is -30 degrees F. And maybe that happens once every 3 years. You’ll want to make sure the BTUs you are accounting for considers that huge outlier. 

There are a few more things you’ll need to consider to help determine the BTU range, hopper capacity and size of the gas stove you’ll need.

Area to be Heated

Determine how much area you’ll be heating with your gas stove.

Decide if you want to try and heat your entire home with your stove and use it as a primary heat source or a single room or as a secondary heat source.

Where to Put a Gas Stove

Freestanding gas stoves have a minimal footprint in a room.

They can be placed 1-3 inches from the back wall and 6-7 inches from the side walls. There are still some other considerations you’ll need to think about.

Safe Clearances

Because of the heat that stoves put out, you’ll need to keep them at least 36 inches away from furniture and draperies. Plus keep them out of the way from main traffic areas, especially if you have small children and pets.

Venting

The exhaust pipe, which can go straight out of an exterior wall or will go up through the roof or chimney must be tightly sealed. This is to prevent flue gases from entering the home. 

You can also install a second intake line to provide outside air for combustion. 

This obviously doesn’t apply to ventless gas fireplaces.

Floor Protection

Most gas stoves are only safe to sit on certain materials. Be sure to check with your dealer to see if your floors are okay or if you need to add a new flooring material. 

A rule of thumb is that stoves must rest on a noncombustible surface, such as stone or ceramic tile to guard against embers. 

Build of Your Home

Before picking out the gas stove, you’ll need to do a walk through of your home to take some notes on a few particulars, such as the layout and build of your home.

These notes will be key parts on which gas stove you choose. Here’s what you need to think of.

Insulation

How well is your home insulated should be one of the first things you consider.

This is because a home that is poorly insulated will need a more powerful gas stove with a higher BTU range to compensate for the lack of insulation.

If your home is well insulated you will not need as powerful of a stove.

You can make an educated guess to determine how well your home is insulated. Basically, newer homes are well insulated, while it’s safe to assume older homes aren’t as well insulated.

Windows

A lot of heat is lost through windows. Take a note of how many windows you have in your home. Also pay close attention to the condition the windows are in.

If there are a lot of windows or windows are in bad shape, then you’ll need to increase the BTU range of your new gas stove.

Ceiling Height

If you have high ceilings, like a cathedral ceiling, you’ll require a more powerful stove with a higher BTU range.

This is because hot air rises and heat can collect above the living area and get trapped where it is of little use.

Climate & Geographical Location

There’s not much you can do here. Unless you want to move.

If you live in an area that is usually warm and maybe it reaches 30-40 degrees a few times a year, you don’t need a powerful gas stove.

But if you live in a cold area, then you’ll want to increase those BTUs.

Vented

If you are wanting to convert your wood-burning fireplace, then it is probably easier to get a vented gas log set.

This is because vented gas log sets are made to be used in existing wood-burning fireplaces with a fully operational chimney.

Vented gas logs must be used with a functional chimney.

They also require the damper to stay open at all times to prevent the build-up of carbon monoxide and other dangerous combustion byproducts.

Burners for vented logs will come as either Standard or American National Standards Institute (ANSI) certified.

If you buy a standard burner, then it is assembled after you receive it. If you receive an ANSI certified burner, then it is already assembled and tested for safety.

Certain cities may require you to buy ANSI certified burners, so you should check with your city before buying a gas log set.

Advantages

• Full, natural flame appearance
• Higher flame
• No BTU limit
• Expansive ember bed helps create a more realistic look
• Flames can touch the logs
• Logs can be rearranged to fit however you think looks best

Disadvantages

• Only about 10% efficient
• Requires venting and the use of a damper clamp
• Your damper must stay open at all times

Vent-Free

Vent-free or ventless gas logs don’t require a chimney or vent to operate.

They are designed to burn at nearly 100% efficiency with a clean, smokeless flame. What does remain is water vapor and carbon dioxide.

If carbon monoxide or other toxic gases remain it will be very minimal and nothing to worry about.

Just like with the older gas sets, the flames are blue and much smaller than the flames created by vented sets.

You can still get a realistic flame, but the flames aren’t as big as the vented sets can provide.

Since water vapor and carbon dioxide are what’s left while burning you may notice an excessive amount of condensation on your windows and throughout the room.

Too much moisture can contribute to mold growth, which can lead to much larger problems.

Any of the following symptoms could point to a venting system problem:

• Damp patches on interior walls or exterior walls
• Peeling wallpaper
• Blistered paint
• Stains on the ceiling around the chimney
• White stains on the outside of the masonry chimney (we call that efflorescence)
• Eroded mortar joints
• Crumbling bricks

Also, since it’s not vented, and the combustion air isn’t able to escape through a chimney, your vent free gas log set could leave an odor when burning.

Ventless gas logs are required to be ANSI certified and cannot be modified in any way once you get them.

Your vent-free gas logs need to be stacked around the gas outlets on the burner to prevent flames from coming into contact with the logs.

If the flames do touch the logs, then carbon monoxide could be produced. Because of this, some states, like California, have outlawed ventless appliances for indoor use.

The BTUs of ventless appliances are limited to a maximum of 40,000 BTUs per hour to help maintain adequate oxygen levels in the room.

This level can be much smaller, to around 6,000 BTUs per hour, depending on the size of the room.

Advantages

• Nearly 100% efficient
• More heat is produced and introduced to your home
• Less gas consumption
• No venting is required
• Equipped with an Oxygen Depletion Sensor (ODS)
• All burners are ANSI certified, tested, and factory assembled

Disadvantages

• Blue, unnatural, and unattractive flame appearance
• 6,000 – 40,000 BTU limit (depending on the room)
• Burners cannot be modified and logs cannot be rearranged.
• More restrictions restrictions
• Sometimes produces an odor while burning
• Increases the humidity levels in your home
• Can cause lung irritation if you have allergies or lung conditions

How it Works

Direct vent fireplaces can work either through a co-linear or co-axial venting system.

Co-Linear Venting

Co-linear systems have two pipes that run parallel to each other. One pulls in fresh air for combustion.

And the other one exhausts combustion byproducts.

This is the most popular venting option for masonry chimneys. And can only be terminated vertically.

Co-Axial Venting

Co-Axial systems have a pipe within a pipe. Both pipes are separated by an inch or more.

The outer pipe pulls in fresh air for combustion, while the inner pipe exhausts the combustion byproducts.

The hot air from the fireplace exits the home, cool air is pulled in from outside and creates a consistent flow of heat. This is known as a convection loop.

Heat Circulation

In your home, cool air is pulled into the convection air intake on the lower part of the firebox. 

The air moves around the firebox before being released back in the room as warm air. You can also get a fan, called a blower, to help push more hot air into the room. 

Some fireplaces have the option to have a heat dump system, which will pull the heat from the fireplace and transfer or dump it into another room. 

Distributing the heat will help lower the clearance requirements above the fireplace. With reduced clearances, some manufacturers will allow a TV to be mounted. 

Heat dumps systems are typically available on hire-end fireplaces with higher heat outputs. 

Direct vent fireboxes are sealed with glass fronts and safety barrier screen. The sealed glass front allows for the direct vent system to work more efficiently while keeping harmful byproducts from getting in your home. 

Tempered glass will come as a standard on most models while ceramic glass is offered as an upgrade. The safety barrier screen is there to prevent direct contact with the heat of the glass.

Venting

As I mentioned before, you’ll need either co-axial or co-linear venting, depending on the chimney and gas fireplace you have.

Co-axial venting is the most common and will consist of flexible or rigid, double-walled pipes that are installed in sections while co-linear venting requires two continuous flexible pipes.

Co-linear venting is the least common since it’s used only for direct vent inserts.

Regardless of the flue outlet, direct vent fireplaces with co-axial venting can exhaust vertically or horizontally. As long as the vent meets the manufacturer’s requirements.

Both vertical and horizontal venting can be maneuvered to avoid joists, beams, and any wall supports that may be in the way.

Some manufactures will even produce proprietary venting systems that must be used specifically with their gas fireplaces.

You’ll need to check the installation manual to see if the fireplace requires manufacturer-specific venting.

Installation

Direct vent fireplaces can be installed in any location in your home, including your bedroom, basement, or even a bathroom.

But you’ll need to check your local building and fire codes first.

Each city and state has specific code requirements.

Safety

When the direct vent fireplaces are properly installed by a certified, licensede professional, they are one of the safest options.

Since they use the outside air for combustion and are completely sealed off from the interior of the home, you don’t have to worry about combustion byproducts polluting the indoor air.

You should still have carbon monoxide detectors installed and have the fireplace inspected by a chimney company annually. The chimney company should clean the fireplace and calibrate the burner.

It’s also very important that the fireplace is not operated without the safety barrier or glass front in place. If the glass is removed, the fireplace won’t work properly and combustion gases will enter the home.

How it Works

Ventless gas fireplaces function on a closed-loop system of indoor air. The cold room air is pulled into the firebox to complete combustion.

The air cycles around the firebox before flowing back into your home as heat.

Ventless gas fireplaces are engineered for nearly 100% efficiency, which means that little to no gases are left after combustion. The remaining gases are usually water vapor and carbon dioxide.

Any dangerous gases, like carbon monoxide, in theory, will be minimal and within safe limits.

As the ventless fireplaces burn oxygen, water vapor is produced, which can leave condensation on the windows in your room.

This is especially true if you’re using a fireplace with liquid propane.

Some moisture isn’t too bad and can actually be a nice source of humidity during the dry winter. But too much and you’ll experience milder or mold.

If you notice too much moisture, you should open a window a little bit to restore balance to the room. Or you can install a hygrometer to keep track of humidity levels and water vapor in your home.

Generally, it’s only recommended to use a ventless fireplace for an hour at a time and only up to four hours in a day to ensure oxygen and humidity levels remain normal. Because of this, ventless fireplaces might not be the best option for harsh winters.

Just like with direct vent fireplaces, some ventless fireplaces will come with a safety barrier screen to provide protection from the fire. These aren’t required. But are recommended for safety purposes.

Installation

Ventless fireplaces offer way more flexibility with installation since you don’t need a chimney. But they do have more restrictions when it comes to location, room size, media modification, and even elevation.

Without a chimney or venting, air quality and oxygen depletion is a major concern.

That’s why ventless fireplaces can’t be installed in small or compact rooms where the oxygen supply is limited.

If you choose to use gas logs as the filler, or media bed, they need to be installed to the manufacturer’s specifications and cannot be modified in any way.

Ventless gas logs are designed to fit together in a specific pattern to keep the flames from touching the logs.

If flames do touch the logs, flame impingement will happen and will create toxic gases.

Without venting for the gases to escape, they’ll just go into your home.

Ventless gas fireplaces are also calibrated by the manufacturer to burn a specific air-to-gas ratio. This makes sure that little byproducts remain after combustion.

We’re fine in Virginia, but if you live in an area with a higher elevation, such as Colorado, you will most likely need to have the gas output adjusted to make up for the higher altitude and thinner air quality.

If you’re looking at having a ventless fireplace installed in your home, you need to research local building codes to find out if there are any installation restrictions and the minimum room size required.

Safety

Overall, ventless fireplaces are considered safe, but it’s a controversial subject because if they aren’t operating properly, you’ll have dangerous gases leaking into your home.

Some states, like California, have outlawed them for indoor use altogether, while others have strict installation requirements.

Vent-free appliances are required to have a built-in oxygen depletion sensor (ODS) on the ignition pilot. The ODS monitors the oxygen level in the room and will shut off if the gas supply dips below the safe threshold of 18%.

The BTU output of ventless gas fireplaces is limited to a maximum of 40,000 BTUs per hour to ensure adequate oxygen is left in the room.

For installations in bedrooms and bathrooms, you’ll see even more limited BTU outputs, around 6,000-10,000 BTUs, regardless of room size.

Since combustion air isn’t able to escape through a chimney, ventless gas fireplaces will intensify any odors already present inside the home.

In fact, air fresheners, incense, or perfumes will strongly affect the odor produced by a ventless fireplace.

Exhaust from the fireplace can cause irritation to the lungs, too.

Carbon Monoxide Dangers

To mitigate the carbon monoxide (CO) dangers, manufacturers often instruct customers to keep a window open while using the fireplace. 

This is easy to ignore, especially when it’s cold out. You don’t want to heat the whole neighborhood, do you?

Most manufacturers have installed an oxygen-detection sensor (ODS) in their ventless fireplaces that will automatically shut down the appliance if oxygen levels become too low. 

The issue here is that the ODS is on the lower part of the unit, near the floor, where it detects cool, fresh, oxygen-filled air and misses the hot combustion gasses as tehy rise and pool toward the ceiling. 

And if the sensor fails, any CO-producing abnormality will go unnoticed and could harm you and your family. 

That’s why many states have simply outlawed ventless gas fireplaces altogether. Many municipalities, too. 

Furthermore, ventless fireplaces have been advised against by various groups, such as American Lung Association, the Centers for Disease Control, the Environmental Protection Agency, and even the Mayo Clinic. 

In particular, these organizations warn against exposure of people with extra vulnerability to CO, such as kids, pregnant women, elderly, and those with pre-existing cardiovascular difficulties. 

I should also mention that there haven’t been any documented cases of fatalities caused by ODS-equipped ventless fireplaces, according to the US Consumer Product Safety Commission.

US Department of Housing and Urban Development (HUD)

In addition to the restrictions mentioned above, the HUD has banned the installation or use of ventless fireplaces in HUD housing. The HUD Handbook (7485.2) states the following:

(1)  Individual Gas or Oil Heaters. Individual gas and oil heaters shall be connected to an approved vent, flue or chimney, and shall have adequate air supply for complete fuel combustion. 

Heaters shall be protected to prevent unsafe human contact or fires and have clearances around them. 

Floors beneath equipment shall be protected against fire and deterioration. Screening shall not minimize required ventilation to the space heater. 

When provided new or replaced, individual controls or units shall not be positioned near the floor, especially in elderly projects or in units for the handicapped.

(2)  Open Flame Heaters. Open flame radiant space heaters shall not be used.

Talk to your Insurance

Adding any type of extra heat to your home can slightly increase your insurance rates. But not informing your insurer can void your coverage completely in the event of a fire. 

So before buying a ventless gas fireplace, obtain a clearance diagram and installation specifications from your insurance company. 

This will detail the amount of space you need to provide between your fireplace and nearby furniture, floor coverings, draperies, and walls. 

Follow these installation guidelines and return the form to your insurance company for approval. Keep in mind that your insurer will be more likely to approve the installation if it’s done by a professional. 

They’ll likely also want it inspected before approval is given. 

Additionally, as I’ve already mentioned, every area has fire and building code restrictions. Be sure to review and follow these guidelines. 

How it Works

B-vent fireplaces have an open front design and operate similarly to wood burning fireplaces.

They pull fresh air into the firebox from inside the home for combustion and then use a vertical pipe to carry away any exhaust and fumes.

Most of the heat produced by the fire will also escape through the venting, making B-vent fireplaces very inefficient.

For this reason, B-Vent fireplaces are most often used for aesthetic purposes rather than as a supplemental source of heat.

Venting

B-Vent fireplaces use a double-walled, insulated pipe to encourage the natural movement of air needed to exhaust combustion gases.

The airspace between the inner and outer pipe provides insulation, preventing heat loss, and allowing the inner pipe to warm up so quickly that warm flue gases can rise up and vent out of the top pipe with ease.

B-vent pipe is the most affordable venting and is relatively easy to install. The major drawback is that it needs to be installed vertically through the home and terminate above the roof.

Installation

B-vent fireplaces are slightly more limited to installation than direct vent or ventless gas fireplaces.

Similar to a masonry chimney, the venting for B-vent fireplaces must terminate vertically through the roof of your house.

This limits the location of installation to areas where you can actually have a vertical pipe run straight up to the roof.

Safety

B-vent fireplaces are very safe. With vertical venting to exhaust combustion byproducts, you don’t need to worry about dangerous gases building up in your home.

Some B-vent fireplaces feature a sensor that will shut off the fireplace if a downdraft occurs and forces exhaust back down the chimney into your home.

Natural Gas

Since pipelines deliver natural gas, it is more common in cities. Today’s natural gas suppliers deliver fuel that contains about 1,000 BTUs per cubic foot.

Advantages

• Usually less expensive than propane gas logs
• Lighter than air (0.65 specific gravity), so it dissipates into the atmosphere after combustion

Disadvantages

• Needs to be hard-piped to any appliance from buried gas service lines
• Natural gas service may not be available in your area

Liquid Propane

Propane has been around as a heating source since the very early 1900s.

It is more common than natural gas in many rural parts of the United States and very popular for heating and cooking.

Advantages

• Contains more carbon dioxide than natural gas
• Burns three times hotter than natural gas
• Can be operated independently of natural gas lines or appliances
• Popular in rural areas since it can be used in areas where natural gas service is not

Disadvantages

• More expensive than natural gas
• Requires installation of a dedicated tank
• Often requires you to sign a contract with a propane dealer to refill your tank

Gas Logs

Gas logs offer the same look and feel of a traditional wood burning fireplace with the added convenience of gas. 

Most fireplaces come with an approved gas log set that’s specifically designed to fit the firebox. 

• Reminiscent of a wood burning fire
• Logs may be molded from real wood logs for a realistic appearance. 
• Creates a rustic and traditional ambiance in your home

Fire Glass

Fire glass comes in an array of colors and can be found in round/oval gems or even crushed glass. 

Fire glass is made from tempered glass and manufactured to withstand harsh weather (good for outside) and extreme temperatures without sustaining any damage. 

• Crystalline ember beds
• Flames reflect off the glass for a contemporary ambiance
• Gives the flames extra texture and depth

Blower

A fireplace blower is a type of fan that helps to blow more heat from the fireplace out into the room.

Blowers don’t make gas fireplaces more efficient, but they will help increase the overall heat output.

Similar to a fan, blowers aren’t silent and will make a whirring noise while in use. It might be a good way to add white noise.

Power Vent

Power venting is used a lot more in commercial settings, such as condos, high rise buildings, and tall apartment complexes where traditional venting won’t work.

A fan is installed in-line with the venting system, either where the venting systems begin (close to the fireplace) or where it ends (near the roof or the wall).

The fan pushes or pulls (depending on where it’s located) the exhaust through the venting and up and out of the building.

This allows for installation through the areas where venting has to run down, across, and then up the roof, rather than straight up, such as through the crawl space.

Power venting solutions are specific to the manufacturer.

Cleaners

You’ll need to keep a good set of cleaners to keep your gas fireplace looking good as new.

You can use a simple glass and hearth cleaner periodically to remove any build up from the inside of the ceramic glass front.

To remove sooty residue from your gas logs or the media, just use plain water and a soft wash cloth.

Harsh cleaning agents can cause gas logs to become brittle over time, making them more susceptible to breakage.

How do you want to start & Control Your Fire?

This is a pretty important decision to make too.

Do you want to worry about using a match to light your flame? Or are you more about showmanship and would prefer a remote? Or do you want to keep it simple enough by just operating a manual safety pilot?

Match Light

Unfortunately, this one is only for natural gas.

There is no pilot; only your logs and a burner. You light your fire just as it sounds: by placing a match or lighter near the burner, then turning on the gas with your key valve.

You can control the flame height with your key valve, which you can normally find on the outside of the fireplace on the wall or on the floor.

Match lights are usually the most affordable and simplest control option.

Manual Safety Pilot

The manual safety pilot (AKA SPK) has a pilot that is manually lighted and stays lit all the time.

It’s very similar to the one you can find on your water heater. You can turn this burner on and off manually by just reaching into your fireplace and turning the control knob.

Remote Control

The manual safety pilot (AKA SPK) has a pilot that is manually lighted and stays lit all the time.

It’s very similar to the one you can find on your water heater. You can turn this burner on and off manually by just reaching into your fireplace and turning the control knob.

How to Hire, What to Look For

When you’re hiring a chimney company, you should always ask the following questions before allowing them to come into your home:

1. Can the company provide references? 
2. Does the company carry a valid business liability insurance policy? 
3. Does the company ensure that a certified chimney technician will be on the job? 

If they guarantee all three of those, then you are in a good spot. The technicians don’t necessarily need to be certified by the CSIA, but I do recommend putting in a bit more due diligence before accepting a certification that’s not by the CSIA. 

This is because certifications are a tricky thing, especially in an unlicensed industry like ours. Any company can craft a list of job-related questions and sell them as an exam and certify those who pass. 

Certifications

I recommend you take a few extra minutes in your research before making your hiring decision to learn more about the certification the company has. Here are a few tips to make sure the certification is reputable: 

• Is the word “certified” just part of the business name or is it an earned designation? 
• Is the certifying body a for-profit business or non-profit? 
• Does the certification need to be maintained and renewed through continuing education as the industry evolves, or is it well enough to be certified through a one-time exam? 
• Is the certifying body well-established or are they relatively new to the scene? New doesn’t mean “bad” but you should make sure the requirements for certification are more or at least equally stringent as those of more established certifications
• Is the mission statement of the certifying body focused on educating and protecting homeowners or is it more focused on making it easier to earn a certification? 
• Does holding the certification require following a code of ethics? 

If you can answer all of these questions, then I think it will be safe to allow the company in your home to work on your chimney.

It doesn’t matter if you are in Roanoke, Lynchburg, Blacksburg, or some other city anywhere in the USA — if you have any questions about the safety of hiring a chimney company, please don’t hesitate to email me at mitchell@patriotchimney.net or call me at 540-225-2626. I’m happy to help!