Can you install underfloor on the first floor?

There are a number of methods of installing underfloor on the first floor and for the minimum running costs the method used should,ideally,have some type of thermal storage (to enable off-peak electricity tariffs to be used). The easiest method to achieve this is to use a beam and block construction with the underfloor mounted in screed. Other methods include using a dry sand/cement mix with the underfloor mounted within this between joists. If engineered joists are used this might not be feasible due to structural considerations and the heat pump might need to operate at a higher temperature to provide adequate heat into the building. Also this type of installation can increase costs.

An over joist method is also available, however again structural considerations need to be taken into account as well as a reduction in ceiling heights and cost considerations.

Other first floor installation methods include using metal plates between joists, while this is acceptable there is no thermal mass and the use of off-peak tariffs might not be effective.