ComfyUI Model Types Explained: Checkpoint, LoRA, VAE, ControlNet & More

Why So Many Model Types?

ComfyUI's power comes from its modular architecture — instead of one monolithic AI model, the generation pipeline is split into specialized components. Each model type handles a specific part of the process.

This guide explains what each model type does, where to install it, and when you need it.

Model Types at a Glance

Detailed Breakdown

Checkpoints

The all-in-one model file. A checkpoint bundles three components:

• UNet — the neural network that predicts and removes noise
• CLIP — converts your text prompt into vectors
• VAE — translates between latent space and pixel space

Install location: ComfyUI/models/checkpoints/

Common models: Stable Diffusion 1.5, SDXL, Stable Diffusion 3.5, DreamShaper, Realistic Vision

LoRA (Low-Rank Adaptation)

Small adapter files that modify a checkpoint's behavior without replacing it. LoRAs are trained to add specific styles, characters, or concepts.

Install location: ComfyUI/models/loras/

How to use: Add a Load LoRA node between Load Checkpoint and the rest of your workflow.

Key point: LoRAs must match their base model version — an SD1.5 LoRA won't work with SDXL.

See the LoRA Guide for detailed usage.

VAE (Variational Autoencoder)

Handles the final conversion from latent space (where the AI works) to pixel space (what you see). A checkpoint includes a default VAE, but you can override it with a standalone VAE for better color accuracy.

Install location: ComfyUI/models/vae/

When to use a separate VAE: If your images have washed-out colors or a color cast, try an external VAE like vae-ft-mse-840000-ema-pruned.safetensors.

ControlNet

Adds structural control — edges, depth maps, human poses — to guide generation. ControlNet models must match the base model version.

Install location: ComfyUI/models/controlnet/

How to use: Load a reference image → preprocess it → feed through Apply ControlNet node.

See the ControlNet Guide for detailed usage.

Embeddings (Textual Inversion)

Tiny files that encode a concept into a prompt token. Used directly in the text field — no extra nodes needed.

Install location: ComfyUI/models/embeddings/

How to use: Type embedding:filename in your prompt.

See the Embeddings Guide for detailed usage.

Upscale Models

AI models that enlarge images while adding detail. Used with the Upscale Image (using Model) node.

Install location: ComfyUI/models/upscale_models/

Common models: RealESRGAN x4, 4x-UltraSharp

See the Upscale Guide for detailed usage.

Separate Components (Flux, SD3, Video Models)

Modern models often ship as individual components instead of a bundled checkpoint:

Version Compatibility

This is the most common source of errors. Models are version-locked:

Never mix versions — an SD1.5 LoRA on an SDXL checkpoint will produce garbage or errors.

Organizing Your Models

As your collection grows, use subfolders to keep things manageable:

ComfyUI/
├── models/
│   ├── checkpoints/
│   │   ├── SD1.5/
│   │   ├── SDXL/
│   │   └── Flux/
│   ├── loras/
│   │   ├── SD1.5/
│   │   └── SDXL/
│   ├── controlnet/
│   │   ├── SD1.5/
│   │   └── Flux/
│   └── embeddings/
│       └── SD1.5/

ComfyUI reads subfolders automatically — models inside them will appear in dropdown menus with their folder path.

Related Guides

• Install Models — How to download and place model files
• LoRA Guide — Using LoRA adapters
• ControlNet Guide — Structural control
• Embeddings Guide — Textual Inversion usage