Floor insulation for moderate climes popular reads.
Insulate floors crawl space.
Instead of installing the foam insulation between floor joists in the crawl space the foam board is installed against the crawl space foundation walls.
Department of energy recommends r 11 3 insulation under floors in warm climates and an r 25 6 to 8 in cold climates.
In those days common building practice was to insulate the floor above the crawl space and to leave the crawl space s wall vents open so any moisture buildup would vent to the outside a.
Insulation also helps to preserve the air quality and reduce energy costs.
Insulation is to keep heat from moving from one place to another so if the crawl space is heated then the insulation is not needed.
In moderate or dry climates without the threat of sustained subfreezing temperatures insulation between floor joists makes sense.
This type of insulation allows for conditioned air to be introduced into the crawl space.
This type of crawl space also allows insulation with an r value of 19 installed in the floor joist if the crawl space and has a permanently installed dehumidifier.
A temperate lower area that will keep upper floors warm while your home s foundation remains in sound condition.
Proper crawl space insulation also can prevent your crawl space from becoming a moist environment that grows and harbors mold and mildew controlling crawl space temperature and moisture is a dual process that works toward a common goal.
Cold air that sweeps through a crawl space meanwhile can lead to cold floors inside the home whether or not the space is wet.
A crawl space under a house helps protect against certain pests but a crawl space with abundant moisture can invite problems including mold wood rot and vermin.
Fiberglass insulation batts or rolls are the most economical and easiest diy choice for insulating between the floor joist in a crawl space.
However the insulation needs to be treated with a fire retardant.
If as you say the floor is only dirt covered with a vapor barrier then there would be heat loss there.
Where winter temperatures are extreme opt for insulating the walls and sealing off the crawl space entirely.