By Dave Miller· off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After blowing two inverters trying to heat my shed with a 2000-watt heater on a 400Ah battery bank, I learned real off-grid warmth comes from insulation, not amps.”
Solar Workshop Heat: Off-Grid Warmth That Actually Works (No Bull)
Stop freezing your arse off in the shed while trying to fix your ute. Off-grid solar workshop heating isn't some fancy sci-fi dream. It's dead simple, cheap, and works if you skip the bullshit. Forget "energy-efficient" marketing fluff. We're talking infrared, radiant heat, and thermal mass. Straight up.
Stop freezing your arse off in the shed while trying to fix your ute. Off-grid solar workshop heating isn't some fancy sci-fi dream. It's dead simple, cheap, and works if you skip the bullshit. Forget "energy-efficient" marketing fluff. We're talking infrared, radiant heat, and thermal mass. Straight up.
Four workshop heating strategies compared: solar air heater, battery heater, thermal mass, and wood backup.
Infrared: The Direct Hit
How it works: Infrared heaters don't warm the air. They warm you and your tools directly, like sunlight. No wasted energy heating empty space. Works instantly. No fan noise. Works in drafty sheds (which all workshops are).
Practical tip: Get a 1.5kW infrared heater. That's enough for a 3m x 3m shed. Runs off 12V/24V solar batteries (no grid needed). Plug it in when you need it. No fancy controllers.
Australian supplier: Energen (energen.com.au) $350-$550 for a 1.5kW model (e.g., Energen 1.5kW Infrared Heater).
Check eBay AU for cheaper options (but skip the dodgy Chinese brands).
Radiant Heat: The Slow Burn (Skip This)
How it works: Radiant systems (like underfloor heating) warm surfaces that then radiate heat. Sounds fancy, but it's overkill for a shed.
Practical tip: Don't waste time on this. Radiant floor heating needs serious installation. For a workshop? Bullshit. Stick to infrared. If you're building a permanent workshop, maybe consider it later. But for now? Skip it.
Thermal Mass: The Heat Bank (Your Secret Weapon)
How it works: Thermal mass (concrete, stone, water) soaks up heat during the day and releases it slowly at night. It's why your house stays warm after the sun sets. For workshops, it smooths out temperature swings.
Practical tip: Build your workshop floor with concrete. Or use a 200L water tank inside the shed. Fill it with hot water from your solar hot water system (if you have one). The tank acts like a heat battery. No extra cost if you already have solar hot water.
Australian supplier: Water Tanks Australia (water-tanks.com.au) $200-$500 for a 200L tank.
Concrete: Local supplier (Boral, etc.) - $100-$150 per cubic metre.
Don't overcomplicate it. A $200 tank + concrete floor = free heat bank.
Real Talk Practical Tips:
Run the infrared heater off your solar battery (not the panels). So you don't drain your system during the day.
Don't buy electric "fan heaters" – they're inefficient off-grid. They waste 70% of your solar power.
1.5kW infrared heater + 200L water tank = warm shed for under $700. Period.
Place the heater near where you work (not in the corner). Direct hit = instant warmth.
Thermal mass (concrete/water) is a bonus. But infrared is the main event. Get that first.
Bottom Line
For under $700, you can have a warm, dry workshop off-grid. No grid. No fancy tech. Just infrared heaters and a bit of thermal mass. Stop overcomplicating it. Get the Energen heater, run it off your battery, and go fix your ute. Done.
⚠️ SAFETY WARNING: Working with electrical systems, structural modifications, or gas installations carries inherent risks. If you are not confident in your abilities, always engage a licensed professional.
It walks through a solar hot water system that works in an off‑grid cabin, showing the exact pumps, controllers and pipe layout you need. The video also covers the wiring and plumbing tips that keep the system reliable without grid power.— Dave Miller
When to Call a Professional
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Electrical work beyond basic 12V DC additions — requires a licensed electrician
Structural modifications to buildings or load-bearing elements
Gas line installation or modification
Solar array installations above safe voltage thresholds
Any work that affects the structural integrity of your property
Always check local regulations and obtain necessary permits before commencing work.
