Fireplace Inserts Demystified - A Complete Guide on How They Work
A fireplace insert is a device that is installed inside an existing masonry fireplace or zero-clearance factory-built fireplace. The purpose of a fireplace insert is to improve the efficiency, functionality and aesthetics of your traditional fireplace.
Unlike an open fireplace, a fireplace insert seals off the opening of the firebox and uses a door with glass panels to contain the fire. This prevents heated room air from escaping up the chimney while the fireplace is in use. Inserts also include a full chimney liner which improves draw and venting. The addition of an insert converts your conventional fireplace into a highly efficient heating system.
Benefits of Installing a Fireplace Insert
- Increases heating efficiency and heat transfer into the room
- Reduces cold air drafts by sealing the fireplace opening
- Controls the rate of burn and contains messy ash
- Option to add blowers to maximize heat circulation
- Can be operated with doors closed for ambiance and safety
- Variety of aesthetic options from traditional to modern
Types of Fireplace Inserts
There are three main types of fireplace inserts to choose from: wood burning, gas, and electric. Each has its own unique pros and cons.
Wood Burning Fireplace Inserts
Wood burning fireplace inserts are designed to burn wood and biomass fuels like wood pellets. Models certified by the EPA are over 65% efficient at converting fuel to heat. This is a major upgrade over the 10-15% efficiency of an open masonry fireplace.
A wood insert consists of a firebox surrounded by a steel shell. Combustion air kits allow for precise control over the burn. Blowers circulate warm air into the room via heat vents. Catalytic combustors in some models further reduce emissions.
Pros of Wood Burning Inserts
- Uses a renewable fuel source if sustainably harvested
- Lower operating costs than gas
- Satisfying ambiance of a live wood fire
Cons of Wood Burning Inserts
- More maintenance than gas or electric models
- Requires storage space for wood fuel supply
- More ash and smoke than other insert types
Gas Fireplace Inserts
Gas fireplace inserts are fueled by natural gas piped directly into your home. They are available as direct vent or vent-free models. Direct vent gas inserts require running intake and exhaust vent pipes through the chimney. Vent-free gas inserts do not need any venting but can only be used intermittently.
How Do Gas Inserts Work?
Gas inserts utilize a gas burner system to combust natural gas, propane, or liquid propane. The flame heats up a ceramic log set or decorative glass crystals to mimic the look of a wood burning fire.
Electronic or millivolt gas valves control the rate of gas flow and flame height. Blowers are commonly built-in to maximize heat transfer efficiency which can exceed 80%.
Pros of Gas Inserts
- Convenient to operate with no cleanup
- Thermostats allow for zone heating
- Very high efficiency ratings
Cons of Gas Inserts
- No wood fire ambiance
- Upfront gas line installation cost if home lacks existing line
- Direct vent models require chimney venting
Electric Fireplace Inserts
Electric fireplace inserts can be installed in locations with or without an existing chimney. They run on standard household electricity and require no venting. Electric inserts are the most energy efficient option, converting nearly 100% of electric energy to heat.
How Do Electric Inserts Work?
Electric fireplace inserts use a heating element fueled by electricity to produce infrared heat. A fan disperses warmth into the room. Realistic logs or crystals fueled by LED lights mimic the ambiance of a fire.
Pros of Electric Inserts
- Most energy efficient option
- Easy plug-in installation
- Flame effect can be used without the heater
Cons of Electric Inserts
- Power outages disrupt use
- Higher energy costs in some areas
- Lacks the ambiance of real burning wood
How to Install a Fireplace Insert
Proper installation is crucial for safe and effective operation of your new fireplace insert. Follow these key steps or hire a certified professional for installation.
Sizing the Insert
Measure the height, width, and depth of your fireplace opening to ensure the insert is properly sized. The surround panels should overlap the fireplace opening by a few inches.
Venting Requirements
Direct vent gas inserts and wood inserts require running stainless steel liner pipes through the existing chimney. An airtight seal must be made using a block-off plate.
Securing the Insert
Inserts are extremely heavy, so they must be well supported. This may require a full steel base underneath. Surround panels should attach securely to the insert or to the fireplace facade.
Finishing Touches
Install any blowers, fans, thermostats, or gas and electric lines at this stage per manufacturer instructions. Finish by surrounding the insert with non-combustible facing materials.
Operating and Maintaining Fireplace Inserts
Operating Wood vs. Gas vs. Electric Inserts
Always refer to the manufacturer's operating manual. Key differences include:
- Wood inserts: Use seasoned dense wood for a longer, cleaner burn. Start with paper and kindling to establish flames.
- Gas inserts: Control the flame height and heat output using a wall switch or thermostat. No ventilation is needed.
- Electric inserts: Turn on simply by plugging in and adjusting the temperature setting.
Cleaning and Maintenance
Gas and electric inserts mainly just require cleaning the viewing glass and wiping down surfaces. Wood inserts need more frequent ash removal and chimney cleaning to prevent creosote buildup.
Troubleshooting Issues
Common problems include clogged chimney or vent pipes, malfunctioning blowers, gas ignition issues, and electrical problems. Attempt basic fixes or call a professional for complex repair needs.
Improving Efficiency and Aesthetics
Efficiency Upgrades
To maximize energy savings, add a chimney damper to prevent heat loss and drafts when the insert is off. Install fans or a thermodynamically controlled blower to circulate warm air. Close doors when not actively fueling a wood stove.
Design Options
Insert facades are available in various materials like ceramic glass, painted steel, and porcelain. Custom fabricated surrounds and hearths can complement your decor. Add wood storage near a wood insert.
Blowers and Fans
Integrated fans accelerate the transfer of heat into the living space, aided by vent grills directing airflow. Quiet, high-volume variable speed blowers maximize heating capacity.
Decorative Surrounds
Non-combustible surrounds and hearths prevent heat damage while giving your insert a beautiful finished look. Granite, tile, and stone enhance the atmosphere.
Costs of Fireplace Inserts
Budget $2,500 to $4,500 installed for a basic wood, gas, or electric insert. More elaborate inserts with special surrounds, blowers, and custom finishes can cost $5,000 to $8,000 installed.
Added Expenses
Factor in these potential added costs:
- Gas line installation for gas inserts
- Electrical work for blowers or a new circuit
- Surrounds, hearths, and custom finishes
- Chimney inspection and repairs
Return on Investment
While inserts involve an upfront cost, most pay for themselves over time through increased home heating efficiency and potential tax credits.
Frequently Asked Questions
What maintenance is required for inserts?
Gas and electric inserts require minimal maintenance like cleaning the glass and replacing air filters. Wood inserts need chimney cleaning annually and more frequent ash removal and gasket inspection.
Can you put an insert in a fireplace without a chimney?
Vent-free gas inserts and electric inserts do not require a chimney and eliminate the need for venting. Most wood and direct vent gas inserts do require a chimney.
Properly installed inserts can heat 800 - 2,000 square feet efficiently. Output ranges from 10,000 BTUs for an electric insert up to 70,000 BTUs for a large wood insert.
We hope this guide covers everything you need to know about how fireplace inserts work and the benefits they provide. Let us know if you have any other questions!