Insulation is crucial for optimizing energy efficiency in electric radiant floor
You definitely need to insulate under the radiant, when you come out of setback, your heat goes to the basement first (path of least resistance) and then when the basement finally gets hot, then the heat will travel to where it is colder.
As UFH designers/suppliers/installers, we would recommend insulation in every case and, not just in the floor. We design systems to produce more than enough heat output to satisfy the needs of any property, however it's the insulation in the property that keeps that heat in where it's required!
But lately, I've begun simply specifying a minimum of 2-inch extruded polystyrene insulation under all heated slabs, even those in basements with no floor coverings.
Simple answer, yes. Something like 20-25% of a home's heat loss comes from the floor. There are foam blocks of the typical insulation. Just need to get the appropriate width for your floor joists.
Installing underfloor insulation is not only a great way to improve your home's energy efficiency, but it also has the added benefit of increasing its Energy Performance Certificate (EPC). The lower your rating, the cheaper it is to heat and light your home.
High Energy Bills
An inadequately insulated crawl space exchanges air freely with the rest of the house. Besides the air quality concerns we already addressed, this air also has temperature differences. Being below ground, your crawl space air is likely cold and clammy.
By adding insulation underneath your slab on grade, you are providing a cushion that allows minor expansion and contraction, while also providing a barrier that separates your concrete slab from direct contact with the Earth's fluctuation in temperatures.
The floor is now ready for the underfloor heating pipework installation. We recommend you use a minimum layer of 50mm Polyurethane insulation. If there is not enough space for 50mm insulation, 30mm can be used. We recommend Polyurethane as it outperforms Polystyrene and its greater density allows use of clip fittings.
Radiant barriers consist of a highly reflective material, usually aluminum foil, which is applied to one or both sides of a number of substrate materials such as kraft paper, plastic films, cardboard, oriented strand board, and air infiltration barrier material.
Fiberglass and mineral wool insulation are two traditional options widely used in a myriad of thermal insulation applications, including under radiant floor heating. Both materials are durable, cost-effective, and offer good thermal resistance, which is a critical factor for effective radiant heat insulation.
In electric underfloor heating, heating mats are laid under the floor. The mats consist of heated cables that are embedded onto a mesh mat with self-adhesive backing. The heating mats are placed on top of a screed (sand and cement) layer to ensure the surface is even.
Insulation in floors plays a crucial role in preventing noise travelling between rooms. Uninsulated, the floor becomes a hollow drum sounding into the room below.
For water underfloor heating systems, insulation is typically installed under the pipes to ensure that the heat is directed upwards into your home. The primary function of underfloor heating insulation is to reduce heat loss downwards into the ground/into the earth, which can be significant in uninsulated properties.
Radiant heating system panels, and their associated components that are installed in interior or exterior assemblies, shall be insulated to an R-value of not less than R-3.5 on all surfaces not facing the space being heated.
It can take a while to get used to the difference, so don't worry if things feel a little strange at first. As a general rule of thumb, your heated floor shouldn't feel hot - it should just not feel cold.
Sweep your floor thoroughly to ensure that it is free from any debris or sharp items which could damage your heating system. If the floor is badly insulated, you desire a faster reaction, or you wish to conserve energy we recommend using Heat Mat Thermal Underfloor Insulation Boards.
Rigid Foam (EPS and XPS)
Expanded polystyrene (EPS) and extruded polystyrene (XPS) are widely used for underfloor insulation due to their moisture resistance and compressive strength. They are particularly well-suited for subfloor installations in homes with concrete or wood bases.
Natural Stone Flooring
Any kind of natural stone or aggregate stone is a good choice for underfloor radiant heating systems. It has good thermal conductivity and doesn't shrink or contract. The great thing about a stone too is how it will retain heat for long periods of time.
The sequence of construction steps is up for interpretation and may vary depending on your contractor or construction manager. Some builders swear by installing the vapor barrier first, while others claim that laying the vapor barrier over the insulation is better. Both may be correct.
XPS foam insulation boards are a popular choice for under-slab applications. They offer high compressive strength, moisture resistance, and durability. XPS is known for its resistance to moisture absorption and is a particularly good match for areas with high groundwater levels.
Installing high-quality under concrete insulation will add to your potential energy savings and improve the environment inside your home. Under slab insulation will help block moisture, toxic gases, condensation, mold and mildew, and even unwanted pests from entering your home.
Improper installation of underfloor insulation can negate its benefits and potentially harm IAQ. For instance, if the insulation is installed without adequate ventilation, it can trap moisture and create an environment conducive to mold growth.
Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.
Water trapped in the insulation batts can also cause mould growth, and leak onto your plasterboard, causing staining and damage. If the insulation is installed behind metal cladding, water damage can cause rust and corrosion.