A kiln is a heavily insulated chamber that heats clay to temperatures far beyond a kitchen oven, roughly 1,800°F to 2,350°F (about 1,000°C to 1,290°C) for most pottery, so the clay turns permanently into ceramic and glazes melt into a glassy coat. Without a kiln, clay stays fragile and dissolves back into mud in water. Most home potters in the US use an electric kiln with a digital controller, while gas, raku and wood kilns serve larger studios and special effects.
This hub explains what a kiln is, how it works, the main types, and how temperatures and cones fit together, then links to every kiln guide on Home Pottery HQ. It is research-based: we draw on maker documentation, Orton's cone chart and dealer data rather than our own firings.
What is a kiln? A plain kiln definition
If you want to define kiln in one line: a kiln is a furnace or oven built to fire materials such as clay, glass or metal clay at high, controlled temperatures. The word covers everything from a tabletop jewelry kiln to a brick wood-fired kiln the size of a room. In pottery, "the kiln" means the piece of equipment that turns shaped, dried clay into finished ware.
So what is a kiln for pottery, compared with the broader word? Merriam-Webster defines a kiln as "an oven, furnace, or heated enclosure used for processing a substance by burning, firing, or drying". That is why the question "what are kilns used for" has such a wide answer: bricks, lime, drying hops and lumber, glass and pottery all use them. A pottery kiln is the version built to reach cone temperatures and hold them evenly. The word itself comes from the Latin culina, kitchen, the same root as "culinary", and Merriam-Webster accepts two pronunciations: "kiln" with the n sounded, and "kil" without it.
What makes a kiln different from an ordinary oven is the insulation, the heat source and the control. Kiln walls are built from insulating firebrick or ceramic fiber that can sit at red heat for hours. Heating elements or burners are rated for those temperatures, and a controller or cone measures heat precisely enough to repeat results.
What does a kiln do? What firing does to clay
Clay that has been shaped and dried is called greenware. It is fragile and still contains water bound into the clay minerals. As a kiln heats, that water is driven off, organic material burns out, and from around red heat the clay particles begin to fuse. At the clay's maturing temperature, part of the body turns glassy, a process called vitrification, which makes stoneware and porcelain dense and strong.
Most potters fire twice. The first, a bisque firing to around cone 06 to 04, makes the ware hard but still porous enough to absorb glaze. The second, a glaze firing, takes the pot to the clay's maturing cone and melts the glaze. Each clay body is made for a range: low-fire earthenware, mid-fire stoneware at cone 5 to 6, or high-fire stoneware and porcelain at cone 10. Matching kiln clay to your kiln's top cone is the first rule of home pottery. See greenware, bone dry clay, bisque firing and types of pottery clay.
How a kiln works
Electric kilns
An electric kiln has coiled wire heating elements set into grooves in soft insulating firebrick. A thermocouple, a temperature probe that pokes into the chamber, reports the temperature to a digital controller. The controller switches the elements on and off through relays to follow a programmed schedule: how fast to heat, the top temperature, how long to hold, and sometimes how fast to cool. When the program ends, the kiln shuts off.
Older and simpler kilns use a kiln sitter instead: a small cone rests in a mechanical switch and, when it bends at temperature, drops a weight that turns the kiln off. Many kilns also have peephole plugs, and many owners add a downdraft vent to pull fumes out during firing.
Fuel-burning kilns
Gas, propane, wood and oil kilns heat by burning fuel inside or beside the chamber, with a flue or chimney to carry combustion gases away. Because the potter can limit the air supply, these kilns can fire in reduction, a low-oxygen atmosphere that changes how clay and glazes look. Electric kilns normally fire in oxidation, with plenty of oxygen.
What happens during a kiln firing, step by step
Whatever the kiln type, a pottery firing passes through the same stages. Knowing them explains why firing schedules start slowly and why opening a kiln too early can crack pots.
- Drying out: below the boiling point of water, any moisture left in the clay turns to steam. Heating too fast here can crack or burst thick pieces, which is why many bisque schedules include a slow start or a hold.
- Burnout: as the kiln climbs through several hundred degrees, organic matter in the clay burns away and chemically bound water leaves the clay minerals. Good ventilation matters most in this stage.
- Quartz inversion: at about 1,063°F (573°C), the quartz in clay changes form and the pot changes size slightly. Heating and cooling evenly through this point reduces cracking.
- Sintering and vitrification: from around red heat, clay particles start to bond. Near the clay's maturing cone, part of the body melts into glass, making it dense and strong, and glazes melt and smooth out.
- Cooling: the kiln cools over many hours. Some glazes benefit from a controlled slow cool. Pots should stay inside until the kiln is near room temperature; opening it hot risks cracked ware and burns.
A digital controller handles these stages automatically through a program, while a kiln sitter kiln relies on the potter to switch settings at the right times.
Kiln temperatures and pyrometric cones
Potters describe firing heat in cones rather than degrees, because the effect on clay depends on temperature and time together. Orton's pyrometric cones are small ceramic pyramids designed to bend at a set amount of heat work. Orton's chart gives these figures for self-supporting cones heated at 108°F (60°C) per hour at the end of the firing:
- Cone 06: 1,828°F (998°C), a common bisque firing
- Cone 04: 1,945°F (1,063°C), bisque or low-fire glaze
- Cone 6: 2,232°F (1,222°C), the usual mid-fire glaze firing
- Cone 10: 2,345°F (1,285°C), high-fire stoneware and porcelain
At a faster rate of 270°F (150°C) per hour, each cone bends at a higher temperature: Orton lists cone 6 at 2,269°F (1,243°C). That is why kiln makers rate kilns by cone, such as "cone 10, 2,350°F (1,288°C)". For the full chart see our pottery cone chart; for heat-up times and outside temperatures see how hot a kiln gets.
Types of kilns
The different types of kilns are easiest to sort two ways: by heat source (electricity, gas, wood) and by how they load (top or front). The kiln types below run from the electric kilns most home potters own to specialist kilns used for particular effects.
Electric kilns
Electric kilns are the standard for home and school pottery. They are clean to run, need no chimney, and with a digital controller they repeat the same firing every time. Sizes range from 120 V test kilns that plug into a household outlet to 240 V kilns of 7 cubic feet or more. See our electric kiln guide.
Gas kilns
Gas kilns burn natural gas or propane. They are favored for reduction effects such as celadons and copper reds, and for large studio loads. They need a flue, gas supply work by qualified installers, and compliance with local fire code. Compare them in gas kiln vs electric kiln.
Raku kilns
Raku kilns are lightweight, usually propane-fired kilns that open while hot so glowing pots can be pulled out and placed in combustible material for smoky, crackled effects. They are used outdoors, following the maker's instructions, fire code and propane safety. See raku kilns and raku pottery.
Wood-fired kilns
Wood kilns, including the long, sloping anagama style, are fired for days by teams stoking wood. Ash melts onto the pots and forms natural glaze. They are community and university projects rather than home kilns.
Test kilns and small kilns
Test kilns are small, often 120 V kilns for glaze tests, jewelry, metal clay and small pieces. Some reach cone 10; others stop at 2,000°F (1,093°C) and suit only glass and metal clay. See our small kiln guide.
Microwave kilns
A microwave kiln is a small insulated pot that heats inside a household microwave, sold mainly for fusing glass. It is not a pottery kiln. See microwave kilns.
Top-loading vs front-loading kilns
Most home pottery kilns are top-loaders: a round or octagonal chamber with a hinged lid. They are cheaper and hold heat well, but you lean in to load. Front-loading kilns have a door like an oven, which is easier on the back and makes loading shelves simpler, but they usually cost more for the same volume.
Choosing a kiln for clay at home
Start with the circuit you can supply, then the cone your clay needs, then size. A 120 V kiln limits you to small chambers; most full-size kilns need a dedicated 240 V circuit installed by a licensed electrician. Most hobby potters fire at cone 6. Size the kiln to about two weeks of your work. Our best pottery kilns for home use compares models, and how much a kiln costs covers purchase, installation and firing costs.
How much does a kiln cost?
A new electric kiln for pottery typically costs about $2,000 to $3,500 at US dealers in fall 2026. In the dealer listings we checked, small high-fire test kilns ran about $1,400 to $2,300, 120 V cone 6 pottery kilns such as the Skutt KM-614-3 about $2,000 to $2,400, full-size 18 inch kilns on 240 V about $2,300 to $3,500, and a 7 cubic foot studio kiln about $4,400 to $5,100. These are bands, not quotes, so check the live price.
The kiln is only part of the bill. Budget for an electrician to install or check the circuit, shelves and posts, cones, kiln wash and possibly a vent. Electricity is modest per firing: we estimate roughly $1 to $16 depending on kiln size at 18 cents per kWh. Our kiln cost guide shows the full breakdown and the math.
Kiln safety basics
- Have a licensed electrician install or check every electric kiln circuit using the maker's stated volts, amps, breaker and receptacle. Never wire a kiln yourself.
- Keep the maker's stated clearance from walls and anything that burns. The kiln case gets hot enough to burn skin.
- Ventilate. Firings release moisture and fumes from clay and glaze; a kiln vent or a well-ventilated space is standard.
- Clay, glaze and kiln wash dust contain silica. Clean wet, never dry sweep, and wear a NIOSH-approved respirator when mixing dry materials.
- For gas and raku kilns, follow the maker's instructions, local fire code and propane safety rules.
- Food safety depends on the glaze label, firing to the stated cone and testing. Never assume a glaze is food safe on your own pots.
Common kiln mistakes
- Firing clay above its rated cone, which can slump or bloat pots.
- Firing greenware that is not fully dry, which can crack or burst pieces.
- Letting glazed pots touch each other or the shelf, which fuses them together.
- Skipping kiln wash on shelves, so glaze drips weld to the shelf.
- Buying a kiln before checking the home's electrical supply.
Every kiln guide on Home Pottery HQ
Kiln buying guides
- Best pottery kilns for home use
- Best electric kilns by circuit
- Best small and mini kilns
- Kiln for sale: new vs used
- How much a kiln costs
- Kilns for beginners
- Test kilns
- Front-loading kilns
- Digital kilns
- Raku kilns
- Microwave kilns
Kiln brands and model reviews
- Skutt kilns and the Skutt Firebox review
- Paragon kilns
- Olympic kilns
- Evenheat kilns and the Evenheat RampMaster review
- L&L kilns and the L&L Easy-Fire review
- Jen-Ken kilns
- Seattle Pottery Supply kilns
- AMACO Excel kilns
- Cress kilns
Kiln comparisons
- Gas kiln vs electric kiln
- Pottery oven vs kiln
- 120V vs 240V kilns
- Front-loading vs top-loading kilns
- Cone 6 vs cone 10
- Skutt vs Paragon
- Skutt vs L&L
- Olympic vs Skutt
- Gas vs electric raku
- Air dry clay vs kiln clay
Firing guides
- How hot does a kiln get
- Pottery cone chart and pyrometric cones
- Bisque firing and bisqueware
- Glaze firing
- Cone 6 firing schedule
- How to load a kiln
- How long to fire pottery
- Slow cooling a kiln
- Oxidation firing and reduction firing
- Cone 6 glazes and cone 10 glazes
Raku, wood and other firing methods
- Raku pottery, raku firing and raku clay
- Wood-fired pottery and anagama kilns
- Soda firing and salt glaze pottery
- Pit firing
- Pottery without a kiln
Kiln setup, safety and maintenance
- Kiln placement and clearance
- Kiln vents
- Kiln insurance and permits
- Kiln maintenance
- Kiln elements, relays and thermocouples
- Kiln controllers and kiln sitters
- Kiln bricks
Kiln furniture and accessories
- Kiln shelves and furniture
- Kiln posts
- Kiln wash
- Kiln cone packs
- Kiln gloves
- Kiln carts and stands
- AMACO Bisque Fix
Sources: Orton Ceramic pyrometric cone temperature equivalents chart; Skutt electrical installation guide and product pages; L&L Kilns knowledge base articles on kiln location, venting, relays and thermocouples; Paragon dealer listings (Sheffield Pottery, Clay-King); Olympic Kilns product data; Merriam-Webster dictionary entry for kiln (definition, pronunciation and etymology); Evenheat heat treat oven pages; US dealer price bands as summarized in our kiln cost guide. Specs checked October 2026.