Generally only ground floors need to be insulated however, you should consider insulating any floors that are above unheated spaces such as garages, as you could be losing a lot of heat through those.
Many homes – especially newer ones – will have a solid concrete floor. This can be insulated when it needs to be replaced, or can have rigid insulation laid on top.
Older homes are most likely to have suspended timber floors. If you have air bricks or ventilation bricks on the outside wall(s) of your house that are below floor level, you probably have a suspended timber floor.
The underfloor space can be accessed via an access hatch which causes little disruption and will be hidden when the install is complete.
At Heat Save, we use Knauf Omnifit 40. This product is non-combustible insulation with the best possible Euroclass A1 reaction to fire classification, and is manufactured using Knauf Insulation's unique bio-based binder, ECOSE® Technology.
Estimates based on typical oil-heated homes. Costs may vary significantly depending on level of work required. Figures are based on fuel prices as of July 2022 from homeenergyscotland.org
*GB based costs.