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Hydronic Underfloor Heating: The Right Choice?


Hydronic underfloor heating is ideal for polished concrete floors

Warm-water underfloor heating is becoming highly popular with Kiwi homeowners for its flexibility and economical running costs compared to other electric radiant systems. There is a substantial setup cost for the boiler or heat pump and to embed pipes into the concrete foundation. But if you’re planning to stay in your home for a while, you’ll see a substantial saving on running costs over time.

If you like the look of polished concrete floors, hydronic underfloor heating is perfect. A well-insulated slab will retain heat well, with sunny rooms only having to be heated during the night due to its thermal mass and passive solar gain. You’ll also save on the cost of flooring material. Alternatively, hydronic underfloor heating also works with almost all flooring options except laminate and laminated wood floors.

The heat source that warms the water flowing through the pipes in many underfloor systems can be upgraded whenever an even more efficient source is developed. For instance, when comparing boilers a decade ago, the most cost-effective hydronic underfloor system were powered by diesel boilers, rather than wood or gas boilers. Thankfully, now cleaner heat can be produced extremely efficiently with less maintenance and without burning fossil fuels by employing air-to-water heat pumps. If you have an older, less efficient boiler, it's worth looking into upgrading.  

Advantages of hydronic underfloor heating powered by air-to-water heat pumps:

  • Ideal for large, open-plan homes with high ceilings and/or lots of glazing.
  • An underfloor hydronic heat pump system will typically use less than a quarter of the electricity of a similar-sized electric element underfloor heating system to run.
  • Along with heating your entire home, some heat pump hydronic underfloor heating systems can also heat your hot water. This could potentially reduce your water heating costs by up to 66 percent!

Geothermal heat pumps are also very efficient and becoming more common in powering hydronic underfloor heating systems. 

General Tips for underfloor heating:

  • Your house must have full poly insulation around the foundation or much of the heat you pay for will be lost.
  • Electric underfloor heating is commonly installed in the bathroom. However, if you’ll only be using the bathroom intermittently, such as an ensuite in a guest bathroom, a high-wall radiant heater or electric fan heater will heat the bathroom up much faster and efficiently than any type of underfloor heating.

This was Part 4 of the Smarter Home Heating for Queenstown Series. Continue to Part 5: Convection Heat - Gas Fireplaces and Gas Heaters.