The Biggest Underfloor Heating Mistakes Homeowners Make (and How to Avoid Them)
- The Underfloor Megastore
- Aug 4
- 3 min read
Installing underfloor heating (UFH) is one of the smartest upgrades you can make - but it’s easy to get it wrong if you don’t know what to look out for. Over the years, we’ve seen the same mistakes crop up again and again.
Here are the most common underfloor heating mistakes people make, and how to avoid them completely.
1. Not Insulating Properly Beneath the System
This one’s a killer. Whether it’s electric or water, UFH needs proper insulation underneath to perform well. Without it, much of the heat gets lost into the subfloor - meaning slower heat-up times and higher bills.
What to do instead: Always use the correct insulation board (like Kingspan, XPS or tile backer) based on your floor finish. It makes a huge difference in comfort and running cost.
2. Buying a Water Kit Without a Design
It’s tempting to just click “add to basket” on an underfloor heating kit - and many companies push that approach hard.
But here’s the problem: your room isn’t “one size fits all,” and a generic kit often isn’t either.
Too often, we see homeowners end up with:
Cold spots where the heating mat didn’t reach
Overheating because the system was oversized
Wasted materials - or worse, not enough to finish the job
Huge pipe spacings - some preset kits use 250mm spacings!
What to do instead: Always get a custom quote and floor plan. It ensures your room is heated evenly, and you only buy what you actually need. That’s why we don’t sell generic kits without proper planning. We offer a full design and quote service instead - completely free - so every system is based on your actual room layout, subfloor, and floor finish.
3. Wrong Floor Finish or Tog Rating
People often don’t realise that certain carpets, underlays, or floorboards can block heat completely.
What to do instead: Stick to low-tog materials under 2.5 total tog. LVT, engineered wood, and porcelain tiles all work brilliantly with UFH.
4. Leaving the Stat in the Wrong Spot
Placing your thermostat near a window, radiator, or direct sunlight? Bad idea.
What to do instead: Install your thermostat away from cold spots, heat sources, or draughty doors. And use a floor probe for accurate control - especially with electric systems.
5. Thinking It’s “Plug-and-Play”
UFH might seem simple, but small oversights during install (like not testing resistance, skipping insulation, or misplacing the probe) can lead to big headaches later.
What to do instead: If you're DIYing, follow the instructions closely - or ask us first. Our support team can walk you through prep, install and post-install checks. If you're hiring a tradesperson, make sure they’ve installed UFH before.
6. Turning It Off and On Like a Radiator
UFH works differently to traditional radiators. It’s designed for slow, consistent warmth - not quick bursts.
What to do instead: Use a smart thermostat to schedule gentle warmth around your lifestyle. It’s more efficient and more comfortable.
Don’t Fall Into These Underfloor Heating Traps
With the right setup, underfloor heating is safe, efficient, and incredibly comfortable. But small mistakes can ruin the experience.
We offer free, honest guidance to help you plan your UFH the right way.
👉 Or drop us a message on WhatsApp - we're here to help.
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