Danfoss Introduction to Hydronic Floor Heating Compendium

MAKING MODERN LIVING POSSIBLE

Introduction to Hydronic Floor Heating

DANFOSS HEATING SOLUTIONS Handbook

Handbook Introduction to Hydronic Floor Heating

Index

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Why choose floor heating? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Where can floor heating be used?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Energy consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Comfort and user behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Temperatures in the room. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Optimum floor temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Temperature distribution in the room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Heat loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Floor heating system dimensioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

For all heat sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Individual room temperature regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Floor construction and system performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2

VGDYA202 © Danfoss 02/2010

Handbook Introduction to Hydronic Floor Heating

Introduction

Why choose
floor heating?

In recent years, underfloor heating has become
increasingly popular. This is due to the fact that
underfloor heating provides a range of opportunities
not offered by traditional heating methods both in
residential and commercial buildings.
However, underfloor heating also offers some
challenges and in order to make the very most
of the opportunities it is important to choose the
right solutions with regard to floor construction and
regulation method.

In most countries, floor heating is the preferred
heating method in new buildings. This is particularly
the case in residential properties, but in office

No ‘”ugly’” radiators which require cleaning.

Furniture can be placed as required without having to take radiators into
consideration.

Danfoss offers a versatile range of products for
complete floor heating systems which are all based
on two main principles:

• Danfoss oor heating solutions are optimized for

easy, fast and safe, installation by the installer

• Danfoss oor heating solutions ensure that the

end-users experience optimal thermal comfort at
minimal energy consumption

buildings and other commercial properties it is
also increasingly popular. Floor heating gives the
end-user a number of benefits:

Floor heating provides comfortable heating as your feet are kept warm while your
head is kept slightly cooler. Most people find this difference in temperature between
feet and head most comfortable.

There is currently a tendency to prefer wood and tiled floors over carpeting. It is
exactly for these ‘”cold’” materials that floor heating can provide extra comfort.

As floor heating supplies heat to the entire room, the differences in temperature that
occur between a radiator and the furthest corner of the room are avoided.

Currently, people are focusing much more on their indoor climate. Increasing
numbers are plagued by asthma and allergic problems and it is therefore important
that thorough cleaning of the home is made possible. Floor heating makes cleaning
much easier. In addition – due to the large heating surface – floor heating means that
less air is mixed and thereby less dust occurs in the room.

Everyone is familiar with the problem of water on the bathroom floor. With floor
heating, water evaporates quickly and the floor quickly becomes dry and warm
again.

With floor heating the room temperature can be lowered 1-2 °C which means energy
savings of 6-12 %.

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Handbook Introduction to Hydronic Floor Heating

Where can floor heating
be used?

Energy consumption

As long as the floor heating system is properly
designed and installed with regard to floor con­struction, cover, materials, etc., there are practically
no limits to where it can be used.

• Floor heating can be used for all oor nishes, tiled

floors, wood (solid/parquet), linoleum and carpet­ing (although the output temperature must be
calculated accordingly)

• Floor heating can be used in all new buildings

• For renovation of existing buildings the installation

height may be a limiting factor, but for this type
of application products like the Danfoss SpeedUp™
and SpeedUp Eco™ systems offering very low built­in height are available

The heat consumption of floor heating has been a
much-discussed issue for many years. There have
been many claims about rising heating bills for floor
heating instead of more traditional radiator sys­tems.
When floor heating was originally introduced, house
constructions were not changed and floor heating
was simply installed by running floor heating pipes
in floors, which otherwise were constructed as
usual.
As the floor heating pipes are embedded in the floor,
automatically, there is a greater heat loss downwards
and thereby a negative effect on the heating bill.

• For renovation of single rooms, oor heating con­nected to the existing heating system and
equipped with a self-acting regulating valve, can
be a good and an economical solution

• For installation of oor heating in the entire prop­erty, wireless controls like Danfoss CF2 control sys­tem is a great advantage, because no electrical
cables need to be wired

• Floor heating can be used with all heating supply

systems. However, the output temperature must
be adjusted so that the floor surface temperature
never exceeds the recommended value (e.g. rec­ommended by the wooden floor supplier).

Today, things have changed – the floor construction
is insulated far better than before and now special
requirements are in place for the installation of floor
heating.
This means heat loss from the building is now typ­ically equally good for houses heated with floor
heating systems as for houses heated with more
traditional heating systems.

But other factors affect energy consumption when
comparing floor heating to other heating options
namely user behaviour and personal comfort. Most
people find it most comfortable to keep their head
a couple of degrees cooler than their feet and the
room temperature when using floor heating can
therefore advantageously be reduced by 1-2 °C in
comparison to traditional radiators, which means
energy savings of 6-12 %.

Comfort and
user behaviour

4

In contrast, most people feel comfortable with warm
fe et – an d the floo r tem per ature can t hen be so h igh
th at t he roo m te mp er atu re b ec ome s u nco mfo rt ab le,
e.g. in bathrooms with tiled floors.
The above examples of user behaviour pull in
different directions when it comes to energy
consumption and show that it can be difficult to
provide an unambiguous answer to what floor
heating means for energy consumption as this will
depend very much on the individual consumer.
However, it can be concluded that compared
to other heating systems floor heating - if used
correctly - will save energy and at the same time
provide better comfort for the end-user.

VGDYA202 © Danfoss 02/2010