Yes, underfloor insulation is a good idea. Underfloor insulation helps to reduce heat loss in winter and heat gain in summer from and to your home. Reducing the need to heat and cool your home will also reduce your energy bills and carbon emissions.
The answer to this question is yes. Underfloor insulation is an extremely efficient and effective way to create thermal efficiency in your home, plus a whole other host of benefits.
The benefits of floor insulation can be significant. 10-20% of heat loss from a building can be through the floors if they're not insulated to a reasonable standard.
Is It Worth Insulating a Floor? Insulating parts of a house typically has a high return on investment. Insulating a floor can net a homeowner around a 10% savings in energy costs, but that number can rise if insulation is added to a home with a crawl space.
Insulation beneath the floors of your home and along foundation walls can help improve energy efficiency and preserve your home's air quality. Without insulation, both warm and cool air can escape through the floors and cause your home energy systems to work harder to keep a stable indoor temperature.
And while adding underfloor insulation will save you between 10% and 20% of heating and cooling energy, the single greatest benefit of underfloor insulation is that it will transform the temperature of your floor from being the external temperature, to being the internal temperature.
Basements are at least partially insulated by the fact that they are typically three-quarters buried in the ground. Crawl spaces should be insulated, too, to prevent the plumbing from freezing in colder climates, to prevent energy loss in HVAC ducts, and to help insulate the house above.
Without it, you could be losing a significant amount of heat in winter and experiencing uncomfortably hot indoor temperatures in summer. If you want to improve indoor comfort, increase your home's energy efficiency and save money on your power bill year round, don't underestimate the power of insulating your floors.
As a general rule, insulation should be replaced or retrofitted every 15 to 20 years. However, it may need replacing or retrofitting sooner depending on the type of insulation installed, the R rating of the original insulation, compression and movement over time, and whether any damage has occurred.
You trap moisture from spills or interstitial condensation up against the timbers within hydrophobic insulation and in turn risk rotting the floor joists.
For most heritage properties, the most effective and appropriate way to insulate a suspended floor and improve its airtightness is to retrofit insulation beneath the floorboards, between the supporting joists (figure 2). See our detailed installation guide for more details.
Heat loss prevention is probably the most significant benefit of insulating your concrete basement floor. Uninsulated basement floors are a major source of heat loss in homes. The basement in older homes in which the floors and walls aren't insulated generally accounts for a third of the home's heat loss.
If the concrete is above the insulation it can sometimes store heat during the day, which helps keep the room warm at night. If the insulation is above the concrete the room will heat up more quickly in the morning. You can still insulate your solid floor even if it doesn't need replacing.
In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.
It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.
FLOOR INSULATION THICKNESSES
Achieving a U-value of 0.25 W/m2K or less would require at least 70mm of Phenolic high-performance foam insulation called Kingspan® K103, or 150mm of EPS100 polystyrene. In the case of PIR Rigid Insulation Boards, thickness of 120mm is normally used.
This will make the crawl space better conditioned and more energy efficient. Insulating the crawl space and air sealing the sub-floor along with rim joist insulation and air sealing is a great way to make sure your entire home is energy efficient.
Do not cover any ventilation with fiberglass insulation and do not wrap wiring with insulation. Insulation can be flammable. Don't allow gaps in your attic. If you do find small gaps, use spray foam or seal with caulk.
Condensation in the crawl space causes fiberglass insulation to sag, making it ineffective at keeping cold air from reaching the floor above. Most crawl spaces have dirt floors, open vents, and porous, uninsulated walls that allow moisture and outside air to enter under the home.
Spray Foam Insulation is Ideal for Use in Crawl Spaces
Most builders and contractors agree that spray foam is a far better product for use in a potentially damp environment. Spray foam repels water, immediately attached to whatever surface you spray it on, and is resistant to biological growth.
Rather than trying to cut off the crawl space from the conditioned upper floors, you should bring the crawl space nearer to the upper floor's temperature by leaving off the underfloor insulation, by insulating the walls and sealing the floor against outside moisture and temperatures.
As underfloor heating operates at a low temperature, it will inevitably take longer to heat the room from the bottom to the top. This means that you can be waiting longer for rooms to become at a comfortable temperature than you would with standard systems.
Unless your home was specially constructed for energy efficiency, you can probably reduce your energy bills by adding more insulation. Many older homes have less insulation than homes built today, but even adding insulation to a newer home can pay for itself within a few years.