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New home building in Ireland in the past decade has incorporated modern technology in many aspects. One of the most popular is the use of underfloor heating. This system is extremely efficient, gives greater even distribution of heat across the area being heated and eliminates the need for sometimes unsightly radiators.
Modern underfloor heating systems are generally either warm water systems or electric systems, the former being far the most popular in Ireland... Systems can be poured into a masonry mix (called a poured floor system or a wet system) or fastened directly to the sub floor (called a sub floor system or dry system).
Above, underfloor heating pipes, before the screed covers them.
Above, distribution control centre of typical home system .
In a hot-water system, warm water is circulated through pipes or tubes that are laid into the floor (usually a solid-screeded floor, although joist-based systems also work well). Various types of pipe are used including PEX, Multi-layer (a composite of PEX, aluminum and PEX) which is also known as Alupex (there is also a version using PERT instead of the PEX) and polybutylene (PB): In general, copper pipes are not normally used because of leakage risk and cost.
Because it offers a good balance between cost and pressure drop, 16 mm diameter tubing is popular 19 mm and (25 mm) tubing are relatively expensive, 10 mm and 13 mm offer too much resistance, which means more energy consumption to pump the liquid through the pipe; and the 16mm tubing is often the minimum size needed for effective thermosiphon
In Europe, including the United Kingdom, 15 mm or 16 mm pipe is commonly used, with some companies offering 10 mm, 12 mm and 18 mm.
However, a system designed to use solar-water heating that circulates by thermosiphon is susceptible to blockage by air bubbles. They are hard to avoid where the tubing lies so flat or may have high spots. Bubbles in the water accumulate in the smallest high spots, finally blocking the flow. A small in-line [[centrifugal pump, 0.05 horsepower (37 W) in rating, can be used for purging. It will circulate water through the tubing fast enough to dislodge an air bubble. The purge pump only activates when the system stagnates and the solar collectors near overheating. When circulation is restored, the pump shuts off.
Gas, oil, solid fuel, or electric-resistance hot water boilers can be used as the source of heat for any underfloor heating system, as can a number of other technologies.
Condensing boilers and ground-coupled heat pumps are particularly well suited as the operation of underfloor heating systems allows them to operate in their most efficient manner. Underfloor heating can run as low a temperature as 35 °C (95 °F), allowing a heat pump to run at a co-efficnet of performance in excess of 4.0, compared to the 3.0 with the temperatures needed for use with wall radiators.
Wet underfloor heating systems can also be used in reverse, where cold water from a chiller or solar cooler is placed in the system taking heat energy out of the building. However, care is needed to ensure that surfaces' temperatures remain above the air's dew point temperature. Otherwise, slipping hazards or mold growth are a concern.
Although it can be more expensive to install than radiators (it can be comparable due to the increasingly competitive market), wet underfloor heating often proves more economical in the long run, particularly in well-insulated larger properties. Energy savings of up to 40% can be achieved compared to conventional heating systems if a condensing boiler or solar thermal system is installed, but even with a standard boiler up to 15% energy savings are normal. The efficiency of condensing boilers is enhanced by water returning at a lower temperature.
By employing full lengths of piping without any joints, wet underfloor heating loops are practically maintenance free. The piping used can have a lifespan of up to 100 years. Reliable materials are critical because repair is difficult. The central heating equipment, pumps, and controls, like others, require periodic maintenance and replacement.
In conclusion, underfloor heating is possibility the best distribution system that is available for the home in Ireland, outweighing the initial cost disadvantage over conventional radiator heating.
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