Choosing the right Underfloor Heating

Whether you are building a new house or renovating an existing property, the type of heating you use is an important decision. It is one that will not only affect your standard of living, but also the cost of your energy bills.

If you are considering underfloor heating, how do you know what the best type of system is for your property? And which are the cheapest and most energy efficient?

To help you decide which type of system is the right choice for your home, some of the most common questions regarding underfloor heating are covered below.

The different types of underfloor heating

Which is the best underfloor heating system for your project.

There are two main types of underfloor heating; Water based and Electric.

Wet underfloor heating works by laying a series of pipes beneath the floor and circulating hot water from the boiler through these pipes, in a similar way to a central heating system.

The floor is indirectly heated by the warm water travelling through the system, and heat is radiated into the room via the surface of the floor.

Electric underfloor heating uses a network of cables or electric matting, which is laid beneath the floor and heats it directly.

The heat up time of an electric system is generally quicker than water based systems, as the floor is heated directly rather than indirectly.

How are the heating systems installed?

Systems installed in new buildings are usually part of the design and fitted during the first fix of construction. Pipes or cables are laid into the screed of the floor, and insulation is laid underneath to prevent downward heat loss. Edge insulation is also fitted around the edge of the floor to avoid further heat loss into the walls.

There are various different designs for the layout of the pipes in a wet system, but they all complete a circuit back to the boiler or heat source, for the water to be reheated. There may be different layouts of pipe for different rooms depending on the amount of heating required, and each room can have its own thermostat to control the temperature.

A manifold assembly of valves, which is usually situated in a cupboard, controls the flow of water to each zone and modifies the system temperature by blending cold water with the hot.

A ‘dry’ electric system can be laid in the same manner in a new building, but will consist of several electrical circuits each connected to the main consumer board independently. Electric systems are often more versatile to install as the mats or cables can be cut to suit any shape, even the most awkward of rooms.

The systems are fully functional just as wet systems are, and rooms can be individually controlled thermostatically or by timer.

Can you retro-fit underfloor heating?

Underfloor heating can be retro-fitted into almost any property, but it is much easier to retrofit a dry system than a wet system. Matting or cable can be laid under an existing floor onto the sub-floor without too much upheaval.

Can you retro-fit underfloor heating?

The floor level will only have to be raised a small amount as the average profile of an electric system is around 3mm; this can save an awful lot of work altering skirting boards and doors in the room.

And because they can be cut to suit the shape of the room, electric systems are the most sensible choice for a refurbishment on most occasions.

Wet systems can be retro-fitted, although it tends to be a great deal more expensive than fitting an electric system.

The floors may need to be dug up for the pipe work to be laid, and the plumbing system needs to be installed and connected to the boiler/heat source.

This is likely to cost more in time and labour to alter existing plumbing than it would when fitting a system as new. The floor may also have to be raised quite significantly, creating further work.

How do the costs compare?

Wet systems generally cost more to install than electric systems, although running costs are usually cheaper. If you are installing the heating with a view to long term costs, then a wet based system will see better savings over time.

Both are considered to be more efficient to run than central heating with radiators, as they suffer less heat loss and run at lower temperatures.

The cost of installing a system is identified by checkyourprice.co.uk as £18 per square metre for a wet system, and £15 per square metre for a dry system. The cost of electrical and plumbing connections for a wet system is £240 per zone, and the cost of the connections of an electric system is £180 per zone.

Running costs for a wet system are cheaper than an electric system because using a gas boiler for the heating rather than electricity is cheaper per KWh of heat output. If a wet system is linked to a renewable source such as solar panels, then the saving could be even greater.

Is underfloor heating more energy efficient?

The heat from an underfloor system is radiated from the entire surface of the floor; this type of heat is partially absorbed by furniture in the room creating an even and moderate temperature throughout. Convection heating via radiators can create ‘hotspots’ and an uneven distribution of heat.

All of the heat rises to leave the floor cold and most of the warmth at ceiling level; much of this heat is lost through the roof and wasted. Underfloor heating keeps the whole room warm from the ground up, and does not suffer the same heat loss.

Wet systems are able to run at 40-50°C, much lower temperatures than central heating systems, which usually run at about 70°C. They also allow a condensing boiler to condense more often and run more efficiently.

Summary

If you are looking at underfloor heating as an option for your hom, it’s important to find out as much as you can about the specific systems you can afford, and assess which, if any, is the right choice for you.

Ask yourself what you aim to achieve by installing it; are you trying to save money on your heating? Are you looking for the extra comfort level? And is the cost justified?

Are you trying to reduce your energy use? Will it make the difference you hope for? And remember to always bear in mind, the property you are going to install the system into; ultimately this will dictate many of your decisions.