Picking a wood stove chimney kit feels harder than it should, because most suppliers hand you a wall of parts and leave the matching to you. We do it the other way around. Nice & Warm carries one curated, fully matched product line of UL 103 HT systems, so the question is simply where the pipe goes. Answer that and the kit picks itself.
How do I choose a chimney kit without guessing?
Start with two facts: the route your chimney takes out of the house, and the diameter of your stove's flue outlet. Route decides the kit family (roof, wall, garage, multi-story, or reline); diameter decides the size within it. Most North American wood stoves use a 6 inch outlet, with smaller or larger stoves at 5 or 8 inches. Match the connector and the Class A chimney to that outlet and you have a working system.
If you would rather not measure twice and order wrong, send us your layout and we will spec it. Our free flue-design help confirms diameter, height, and the exact part list before you buy, which is the surest way to avoid a costly mismatch.
Through the roof vs through an exterior wall vs through the attic
These three routes are the most common, and they map cleanly to three kits.
- Straight up through the roof. The stove sits below the roofline and the chimney rises through the ceiling, attic, and roof in one vertical run. This is the warmest, best-drafting layout. Use a through-the-roof wood stove kit, which includes the connector pipe, ceiling support, Class A pipe, attic insulation shield, flashing, storm collar, and cap.
- Out through an exterior wall, then up outside. The stove pipe turns, passes through a wall thimble, and the Class A chimney climbs the outside of the house. A through-the-wall chimney kit bundles the wall support, tee, brackets, and the exterior Class A run. It is the go-to when an interior vertical path is blocked.
- Through the attic (still up through the roof). The attic is not a separate destination; it is part of the through-the-roof path. The kit you want is the same through-the-roof kit, with an attic insulation shield included so the Class A pipe keeps its clearance where it passes the framing and insulation.
Interior routes draft better than exterior ones. A chimney run up the cold outside wall is more prone to weak draft and creosote, so where you have a choice, up through the roof wins.
What kit do I need for a multi-story house vs a single-story?
A single-story home with the stove on the main floor is the simplest case: a standard through-the-roof or through-the-wall kit covers it. A multi-story house needs more vertical Class A pipe and, critically, intermediate support so the chimney's weight is carried at each floor rather than hanging from one bracket.
For two or more stories, use the multi-story Class A chimney kit, which is built around UL 103 HT pipe and the extra firestop and support hardware those longer runs require. If your stove is on an upper floor or the run is unusual, this is exactly the case where free flue-design help pays off, because support spacing is easy to get wrong.
Which kit for a wood stove in a garage (inside run vs external run)?
A garage stove is handled like any other room, with one decision up front: does the chimney stay inside the garage and exit the roof, or run up an outside wall?
- Inside run. If the chimney rises inside the heated space and through the roof, choose the inside-the-garage chimney kit. The interior path keeps the flue warm and drafting well.
- External run. If the layout pushes the chimney outside, the outside Class A flue kit carries the run up the exterior wall with the right tee and bracket support.
Either way, confirm your local clearances and any garage-specific requirements before ordering. Stoves in garages can carry extra local rules, and we will flag those when we design your flue.
What do I need to reline an existing masonry chimney?
If you are connecting a wood stove to an existing brick or block chimney, you usually do not need a full Class A system. You need a stainless liner sized to the stove. A chimney liner kit includes the flexible liner, top plate, rain cap, and connector so the masonry flue safely vents the stove. Most wood stoves take a 6 inch liner; smaller stoves may take 5 inches.
Relining is the right call when the existing flue is oversized, unlined, or deteriorated. A correctly sized liner restores draft and protects the masonry, and it is far less work than building a new chimney from scratch.
Can I use a 5 inch flue on a 6 inch stove?
No. Match the chimney to the stove's flue outlet, not the other way around. Putting a 5 inch flue on a stove with a 6 inch outlet restricts the exhaust, weakens draft, and can cause smoke spillage and faster creosote buildup. If your stove has a 6 inch collar, run a 6 inch connector and a 6 inch Class A chimney or liner. Reducing diameter is not a money-saving shortcut; it is a safety and performance problem.
What is in a complete kit, and Class A vs connector pipe
A complete kit is the full path from your stove to the rain cap, with every bracket, support, and flashing in between. Knowing the two pipe types makes the parts list click.
- Connector (stove) pipe is the single-wall or double-wall pipe inside the room, between the stove outlet and the point where the chimney begins. It is not a chimney and is never run through a wall, ceiling, or roof.
- Class A insulated chimney pipe is the UL 103 HT-listed, insulated pipe that passes through the building and outside. This is the part that is rated for the high flue temperatures of a wood fire.
Single-wall connector pipe is the most economical indoor option but needs the most clearance. Double-wall connector pipe costs more and allows tighter clearances, which helps in compact installs. Our Class A range and connector options live in the Class A chimney and stove pipe section, and every kit pairs the two correctly so you are never matching parts by hand.
Spec table for installers
| Install scenario | Kit family | Core pipe | Typical diameter |
|---|---|---|---|
| Through the roof / attic (single story) | Through-the-roof kit | Class A UL 103 HT + connector | 6 inch (5 or 8 as stove requires) |
| Through an exterior wall, up outside | Through-the-wall kit | Class A UL 103 HT + tee + connector | 6 inch (5 or 8 as stove requires) |
| Two or more stories | Multi-story kit | Class A UL 103 HT + intermediate support | 6 inch (5 or 8 as stove requires) |
| Garage, interior run | Inside-garage kit | Class A UL 103 HT + connector | 6 inch (5 or 8 as stove requires) |
| Garage / exterior run | Outside Class A kit | Class A UL 103 HT + tee + brackets | 6 inch (5 or 8 as stove requires) |
| Existing masonry chimney | Liner kit | Stainless liner + cap + connector | 6 inch (5 for small stoves) |
What do US fire-safety codes require?
Your kit has to satisfy clearances and chimney height, and those are set by national standards your local code adopts. Quote them to your inspector and build to them exactly.
Single-wall connector clearance: Per NFPA 211, single-wall stove pipe (the connector pipe inside the room between the appliance and the Class A chimney) must maintain at least 18 inches of clearance from any combustible wall, ceiling, or framing.
Double-wall connector clearance: Per NFPA 211, double-wall stove pipe is rated for reduced clearances typically 6 inches from combustible walls and 8 inches from ceilings (verify exact clearance with the specific UL-listed product).
Class A chimney clearance: Class A insulated chimney pipe, when UL 103 HT-listed for wood-burning, maintains a minimum of 2 inches clearance to combustibles per the standard listing. Always verify the exact clearance specified by the manufacturer's UL listing for the specific product.
What is the 3-2-10 rule for chimneys?
It sets how high your chimney must finish above the roof.
The 3-2-10 rule (NFPA 211 / IRC R1003.9) requires that a chimney extend at least 3 feet above the highest point where it passes through the roof, AND at least 2 feet higher than any portion of the building, structure, or obstruction within a 10-foot horizontal radius.
Your kit must include enough Class A length to meet this on your specific roof pitch.
Who can install it?
You can. Most homeowners install their own chimney kit, and the job is straightforward if you follow the manufacturer's instructions and local code. Our kits ship with everything you need, and our free flue-design service confirms the parts list and layout before you start, so there are no surprises on the roof. Step-by-step guidance is in our installation guides.
If you prefer to hire a pro, look for a CSIA-certified sweep (Chimney Safety Institute of America) or an NFI-certified installer (National Fireplace Institute). Some insurance carriers and local jurisdictions require a permit or inspection, so check with your town before you start, whether you do it yourself or hire it out.
Key takeaways
- Pick your kit by route first (roof, wall, garage, multi-story, or reline), then size it to your stove's flue outlet.
- Up through the roof drafts best; an exterior run is the fallback when an interior path is blocked.
- Multi-story runs need intermediate support; garage installs need a clearance check.
- Reline an existing masonry chimney with a sized stainless liner, usually 6 inches.
- Never down-size the flue below the stove outlet (no 5 inch flue on a 6 inch stove).
- Every kit is a complete, UL 103 HT matched system, and free flue-design help confirms it before you order.
Get the right kit the first time
You do not have to assemble this from a parts list. Tell us your install scenario and stove outlet, and we will match you to one complete, code-compliant system from our curated line, with the diameter and height confirmed in advance. Every system is built around UL 103 HT pipe rated for 1000°F continuous use, ships from the nearest US warehouse, and is backed by a limited warranty (100% replacement for the first 15 years, 50% of original price thereafter, for as long as the original owner keeps the system). Returns are simple too, with a 14-day no-questions-asked policy for added peace of mind.
Call a chimney specialist at 888-8340-880 or browse the complete wood stove chimney kits to get started.
Need More Information?
Visit our FAQ page, browse our installation guides, or contact our team through our advice page.
