Which radiant floor heat is best?
Eco home promotes air radiant systems (e.g. Legalett) aren't direct electric resistance mats more efficient. Seems air and water systems use power to heat the air/water which is not as efficient? That's a question, not a statement.
Of the different types of radiant floor heat, the efficiency isn’t affected as much by the delivery system, meaning whether it is an air heated floor, electric mat radiant floor, or liquid glycol hydronic radiant floor. What matters most is the amount of insulation below the floor and the fuel source, whether that’s gas or electric. You may have seen this page but have a look if not, there is a comparison of the pros and cons of the different systems –
Which is the best type of radiant floor?
To give a quick summary though, forget gas and just think electric – the efficiency of electric resistance heating doesn’t change based on how it’s delivered. A baseboard heater, hair dryer, toaster, boiler or electric mat floor generate the same amount of BTUs per Watt whether you are heating a wire, or a wire heats air or water and then forces it through tubing in a floor. So hydronic, air heated floors or electric mats are effectively the same in efficiency.
The differences are subtle, but in the case of the air heated floors, the heater is in the floor itself so all the heat is contained in the floor rather than escaping into the mechanical room where the boiler and manifolds are all exposed. So the heat is contained in the floor, but also distributed a bit more equally throughout the house. It just ads abit of comfort and balances the heat better through the house.
Air also has a lot less latent heat in it, so when the thermostat hits the desired temperature and shuts off the heat, it will stop heating. A hydronic floor has so much heat in the water that oftentimes you can overshoot the thermostat setting and overheat as it is released. Air tubes are also a bit easier to install, and less risky to damage during install or afterwards. If you pierce a pex tube in your floor and don’t know it and fix it, the system won’t work. If you put a screw into an air tube it makes no difference.
thanks a million; i'm between air and electric mats which seem cheaper overall. Your thoughts?
Is it a renovation or new build? if for example you're talking about adding electric mats and tiles or something to an existing floor then electric mats are for sure the cheapest option. The air heated floor by Legalett is more for new builds.
Legalett supplies engineered slab on grade prefab kits (see more here) with the air heated floor, so if you're building a new home and looking for radiant floor heat the the air heated floor system would be likely be cheaper than mats, and it offers the option of gas or electric (electric being our preference of course for ecological reasons).