Gas Inserts
Since 2010, Thompson's Hearth & Home has proudly sold and installed Kozy Heat gas inserts, a trusted American brand that's been delivering quality and innovation for decades.
Kozy Heat is a three-generation, family-owned business based in the small town of Lakefield, Minnesota. They're committed to American manufacturing, sourcing their steel from a U.S. company in Iowa—one of the few fireplace makers to do so. What truly sets them apart is their in-house production of ceramic logs: every log is hand-painted by skilled artisans right in their facility, creating remarkably realistic flames and embers that bring the look of a traditional wood fire to life.
Gas inserts from Kozy Heat are engineered to efficiently heat a single room or even your entire home using either natural gas or propane. They're clean-burning, user-friendly, and highly efficient, providing reliable warmth without the mess of wood, ash, or frequent maintenance.
A standout benefit for homes in the Pacific Northwest is their performance during power outages. All our Kozy Heat gas inserts feature electronic ignition with a standard standing pilot option. This keeps the flue preheated in cold weather for smooth starts, while also allowing a switch to intermittent pilot mode to save $15–$20 per month on gas costs. No electricity needed—these inserts keep heating your home using the battery backup when the power goes out.
We handle every installation with our own in-house employees—no subcontractors. We're fully licensed, bonded, and insured, and we're one of the few NFI-certified (National Fireplace Institute) dealers in the area. NFI is the only nationally recognized certification program in the U.S., ensuring our team has the highest level of expertise for safe, professional installations.
Every Kozy Heat gas insert we carry is furnace-rated, meaning they deliver exceptional heating performance—often rivaling wood inserts in effectiveness. Heat output depends on factors like BTUs, efficiency ratings, and high-quality materials used in construction, and Kozy Heat excels in all areas.
Commonly Asked Questions
Q: What's the difference between a gas insert and a gas fireplace? A: A gas insert is designed to fit ("insert") directly into an existing wood-burning fireplace opening—typically a masonry or pre-built wood fireplace. It converts your old wood setup into a clean, efficient gas system without needing major structural changes.
A gas fireplace (also called a built-in or zero clearance gas fireplace) is installed directly into the home's framing or wall structure. It's perfect for new construction or major remodels where you're adding a fireplace from scratch—no existing fireplace or chimney required. This gives you more flexibility in size, design, and placement.
Q: What areas do you cover? A: We primarily serve the Eastside side, including Issaquah, Bellevue, Sammamish, Fall City, Snoqualmie, North Bend, and surrounding communities. By keeping our service area focused close to our showroom in Issaquah, we can respond quickly to any needs—whether it's installation, service calls, or troubleshooting. This proximity is key to delivering fast, reliable support and keeping our customers happy!
Q: How do we get started? A: Simply email us or bring in a photo of your existing fireplace along with basic measurements, width and height, of the opening. This allows us to quickly assess compatibility and recommend suitable models. If anything looks unusual or needs closer inspection, we'll arrange an in-home visit at no extra charge to ensure everything is perfect.
Q: How much are gas inserts? A: We focus exclusively on premium gas inserts made in the USA by Kozy Heat because they deliver superior value in quality, performance, and longevity. After comparing options across the market, we consistently find that our inserts provide better materials, more reliable gas valves, advanced remote controls, stronger electronics, quieter fans, higher efficiency, and superior fit and finish—at a comparable installed price to lesser brands.
Our fully installed gas inserts typically range from $5,400 to $6,900 (prices as of 2026; subject to model, options, and any custom needs). This comprehensive package includes:
The insert unit itself
Shipping and delivery
Vacuuming of your existing fireplace
Dual chimney liners all the way to the top (many installers cut corners here)
Professional setup and connection
Thermostat-controlled remote
Electronic ignition with battery backup
Hookup to existing gas supply in the fireplace
Plug-in to the nearest electrical outlet
No hidden fees for the basics—everything needed for a safe, turnkey installation.
Q: Will your inserts work in a power outage? A: Absolutely—yes! We've carefully selected inserts that operate reliably without electricity. Whether they use a standing pilot or electronic ignition, they light and run during outages. The blower (fan) and lights will not work, but our inserts will heat 1500-2000 square feet based on 8’ ceilings and outside temperatures of 40 degrees. We've seen other brands that require batteries only in emergencies or limit operation to just an hour or two without the fan—our systems avoid those limitations for true peace of mind in the Pacific Northwest's unpredictable weather.
Q: How much is an additional gas line if needed? A: When installed alongside a new gas insert, we charge $425 for the first 10 feet of gas line, plus $25 per additional foot thereafter. This covers professional installation, materials, and pressure testing to code.
Q: Is there a way for the fan cord not to show? A: Yes! We can refer you to a licensed electrician who will install a discreet outlet inside the fireplace for $425. If you'd prefer us to handle payment on your behalf, the total is $475—convenience included.
Q: Is a permit needed? A: Yes, a mechanical permit is typically required for gas fireplace/insert installations to comply with local building codes. It's ultimately your choice whether to pull it yourself through your city or county building department, or we can handle the permitting process for you (additional fees apply either way).
If a new gas line is involved, the installation is split into three separate trips (to accommodate inspections), which adds $250 to the total:
Gas line installation and pressure test (inspector approves)
Insert installation and connection (inspector approves)
Final inspection of the complete setup (inspector approves)
Your insurance provider prioritizes that the installer is licensed, bonded, and insured (which we are), providing you with full recourse if ever needed.
Q: What if our fireplace is arched? A: No problem at all—we specialize in arched openings! Our team has extensive experience customizing inserts to fit beautifully in arched fireplaces. Check out our photo gallery on the website (or ask in the showroom) to see real examples of our arched installations. We love the challenge and always deliver a clean, professional result.
Q: What makes some inserts better than others? A: With so many brands and designs available, the differences really show in long-term performance, efficiency, and reliability. After years of selling, installing, and servicing thousands of units, we've honed in on three key factors that separate the best from the rest:
Firebox Construction — Look for a robust, well-built firebox. Some use thick, welded steel, but that can reduce efficiency due to lack of heat transfer through a thick material. Thinner, high-quality materials are often joined with a superior button-locking process (strong and durable) rather than rivets, which can loosen over time, causing efficiency drops or intermittent issues.
Glass Quality — Premium inserts use ceramic glass (not cheaper tempered glass). Ceramic allows up to 70% more infrared radiant heat to transfer through it, delivering the cozy warmth you expect—tempered glass only allow 10-30 percent of the radiant heat to pass through it.
Control System — The heart of modern inserts is the electronics. We've found the ProFlame 2 system (from SIT) to be one of the most reliable on the market—proven through extensive real-world use. It offers seamless intermittent/standing pilot options, precise flame control, thermostat functions, fan/blower management, and more.
Quick checklist for a top-tier insert: No riveted firebox, ceramic glass, and ProFlame 2 controls. These features mean better heat output, longer life, fewer service calls, and a more enjoyable experience overall.
Q: How much does it cost to operate a natural gas insert?
A: 18 - 50 cents per hour. To figure this out you need to know that natural gas is sold in the form of therms. A therm equals 100,000 Btus and gas inserts range between 10,000 - 40,000 Btus and usually have a turn down of 50%. That being said a unit that runs at 25,000 Btus per hour will use 100,000 Btus in a 4 hour period. Currently PSE is listing natural gas at $1.20 per therm which means a 25,000 Btu gas insert will have a cost of 30 cents per hour. This same insert has a turn down of about half reducing the operating cost to about 18 cents per hour.
Q: Can we put our TV above the fireplace?
A: Yes, but you want to make sure that the TV is protected by a mantel.
If you have made it this far then you might be interested in looking at the brochure!
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