Better Sauna Insulation for Your Home: Why We Use Rockwool
If you’re considering a custom indoor sauna, insulation might not be the first thing on your mind — but it should be.
Many pre-built or kit-based sauna companies cut corners when it comes to insulation, often using standard R-13 fiberglass that’s commonly found in home walls. And while that might work in your living room, it falls short in a high-heat, high-moisture environment like a sauna.
At Midwest Sauna & Steam, we do things differently.
We use Rockwool ComfortBatt® or equivalent mineral wool insulation — a dense, sauna-grade solution that delivers far superior thermal performance, moisture resistance, and long-term durability.
Let’s break it down.
🧱 The Problem with Standard R-13 Insulation
Many sauna kits on the market include R-13 fiberglass insulation, the kind you’d find in a typical interior wall. While it may be familiar and affordable, it comes with serious downsides when used in a sauna:
Poor moisture resistance — fiberglass insulation absorbs and traps water, which can lead to mold and mildew
Compresses easily — over time, it can sag and lose R-value in the vertical wall cavities of a sauna
Low thermal mass — it can’t withstand or regulate sauna heat effectively, leading to heat loss and inefficiency
Irritating to install — and even more problematic if you ever need to open up the wall for repairs
🧊 Why We Use Rockwool Instead
Rockwool (also known as mineral wool) is engineered to thrive in extreme environments — making it the ideal insulation choice for saunas. Here's why we prefer it:
✅ Moisture Resistant
Rockwool is water-repellent and won’t absorb or retain moisture, helping prevent mold, mildew, and rot inside your walls. That’s huge in a sauna, where high humidity is the norm.
✅ High Heat Performance
It’s rated for temperatures up to 1,000°F — so you get consistent heat retention without insulation breakdown over time. Your sauna stays hotter, longer, with less energy loss.
✅ Sound Dampening
It also has natural sound-absorbing properties, helping create a more peaceful, quiet retreat — especially if your sauna is near a living space.
✅ Fire-Resistant & Sustainable
Rockwool is made from natural stone and recycled materials, and it’s non-combustible, giving your home an added layer of safety.
✅ Dense & Durable
It holds its shape and R-value over time — no sagging, no settling, no insulation gaps.
💬 Why It Matters for You
You may not see what’s behind your sauna walls, but it matters just as much — if not more — than the beautiful wood and lighting you see every day.
By using Rockwool, we help ensure your sauna:
Heats faster and stays hotter longer
Uses energy more efficiently
Lasts longer with fewer maintenance issues
Resists mold, rot, and breakdown — year after year
🪵 Better Sauna Builds Start with the Right Materials
At Midwest Sauna & Steam, we’re not just building for today — we’re building for 10, 20, 30 years down the road. From our vapor barrier techniques to the wood and insulation we choose, every decision is made to protect your investment and enhance your experience.
That’s the difference you get when you work with a local builder who cares about the details you don’t see — but will definitely feel.
📍 Custom Indoor Saunas | Built in Ohio
🛠️ Handcrafted | Never Pre-Fab
🔗 midwestsaunasteam.com
📧 midwestsaunasteam@gmail.com
