Honeywell can control underfloor heating in many ways. Before trying to select the controls, it may help to understand the principle of underfloor heating.

Introduction to Underfloor Heating

Underfloor Heating is commonly used in mainland Europe and is becoming increasingly popular in the UK. It has a number of advantages and disadvantages over a conventional wet radiator system.

Advantages 

•        Even distribution of heat across the room

•    Easy to install requiring no special skills

•    Unobtrusive

•    No restriction on the placement of furniture

•    Quiet in use

•    Very little maintenance is required

•    Individual room temperature control

•    No risk of contact with hot surfaces

•    Fabric temperature of building maintained

Disadvantages 

•    Long heat up period

•    Requires major disruption on existing buildings

•    Long cooling down period

•    Cannot respond rapidly to quick temperature changes

•    Choice of floor finishing requires careful consideration

•    Changes of floor finish may affect performance.

How does an Underfloor Heating System Work ?

Generally speaking, most underfloor heating systems are warm water (wet) systems although electric (dry) systems are available. For wet systems, pipes are buried in screed, or run underneath the floor surface. Underfloor heating systems operate by transferring heat from a very large surface, which is only slightly hotter than the room. Radiator systems transfer heat from a very small surface, which is much hotter than the room, which is very hot. 

Typically, the temperature of the water in the underfloor heating system pipe is 45 – 65^oC (compare this to approximately 80^oC flow and surface temperature of a radiator system) and this warms the floor to a temperature of 25 – 28^oC, which is comfortable to walk on. In order that the whole floor area receives heat, the layout of the pipework should be considered carefully. The supplier of the underfloor pipework will be able to provide details on the best layout for your application. 

At the design stage there are a number of points that need to be considered: 

•     Insulating affects of floor finish e.g. Carpets

•     Protection of floor finish from cracking

•     Accommodation of thermal gains e.g. conservatory

•     Location of manifolds

•     Zoning requirements

•     Boiler/pump position and size

There are several different pipework layouts which can be used. No matter what the layout is, this will not affect the control requirements. 

There are several ways to control an underfloor heating system heating and these will be discussed later. 

Where can underfloor heating systems be used? 

Underfloor heating systems are suitable for both domestic and commercial applications. It has a particular advantage in public areas where exposed hot surfaces can be dangerous. 

Gas, oil or solid fuel boilers can be used as the source of heat for any underfloor heating system. Condensing boilers being particularly suited as the operation of underfloor heating systems allows them to operate in their most efficient manner. 

Underfloor heating systems can be fitted as complete systems in new or major refurbished properties, extensions to existing houses such as conservatories or single or multiple rooms in a house. 

It is possible to combine both underfloor systems with radiator systems. For example, the ground floor could be heated by an underfloor system whilst the 1^st floor is heated using a wet radiator system or radiators can be fitted in the bathroom and lavatory in homes where the main system is underfloor heating. 

To control underfloor heating systems, Honeywell can offer a wide range of traditional controls and also the more sophisticated Hometronic system. The selection of these controls for underfloor heating will be discussed later.