Why is my radiant heat not getting hot?

Author: Mr. Dorcas Ebert  |  Last update: Sunday, May 25, 2025

This can be caused by a faulty thermostat or zone value or damaged heating cables or mats. The culprit could also be tripped circuit breakers, where your electrical box is tripped by faulty or broken wiring, or over-consumption of electricity.

Why is my underfloor heating not getting up to temperature?

If you underfloor heating system is not reaching temperature this may be due to downward heat loss. If your heating system has been installed on an un-insulated concrete slab or over an unheated space and insulation boards were not used, there will be a considerable amount of heat loss into the sub floor.

Why is my heat on but not getting hot?

Change the furnace filter on a regular basis to prevent airflow problems. Closed or obstructed vents can also cause it to feel like the furnace isn't making enough heat, because not all of its hot air makes it through the vents into your living areas. Check all vents to make sure louvers are open.

How do I get more heat from underfloor heating?

The heat output of an underfloor heating system can be significantly increased by installing high-quality UFH floor insulation alongside your system. Insulation improves a system's performance, improving heat-up times and ensuring the heat produced by the system will not escape the space.

Why does radiant heat take so long to heat up?

The radiant floor system takes much longer to respond to air temperature changes. So if the convective heat source took over and shut off the radiant system, then the convective heat crapped out...the woodstove burning down...it would take some time for the radiant floor to begin heating up again.

How to Fix One Radiator Not Working - Plumbing Tips

Why is my radiant heater not getting hot?

This can be caused by a faulty thermostat or zone value or damaged heating cables or mats. The culprit could also be tripped circuit breakers, where your electrical box is tripped by faulty or broken wiring, or over-consumption of electricity.

Why is my underfloor heating so slow to warm up?

Heat Loss

Heat loss can dramatically affect how long your underfloor heating system takes to warm up. Minimising heat loss through proper insulation where heat is most likely to escape is key —like windows, doors, and walls.

What is the best thermostat setting for underfloor heating?

This is typically somewhere between 21°C and 27°C. You should also take into account how many people in your household might use a particular room regularly and for what purpose. As a general rule, it is recommended you set your underfloor heating manifold to within a temperature range of 35°C - 45°C.

How to remove trapped air from underfloor heating?

In order to remove the air you will need to:
  1. Isolate all of the UFH zones except for the zone that is not heating up.
  2. Remove the actuator.
  3. Connect a hosepipe to the flow valve on the manifold and connect to a cold mains tap.
  4. Connect a hose to the drain off point on the manifold and take out to waste.

Why is my heating not getting up to temperature?

Radiators might not be getting hot due to trapped air requiring bleeding, a malfunctioning boiler or central heating pump, thermostatic radiator valves that might be stuck or set too low, or the central heating system having sludge or rust which causes blockages.

Why isn't my heat reaching temperature?

Some of the most common thermostat issues include:

The thermostat is broken, not properly level, or dusty. The thermostat needs to be recalibrated. There is loose wiring causing a thermostat issue.

Why is my house not getting warm with the heating on?

This problem often points to inadequate circulation of warm air. It could be due to blocked vents, a failing HVAC fan, or issues with the furnace itself. Ensure that furniture or drapes are not blocking your vents.

Why is my floor heating not warm?

Underfloor heating not working could be a result of air in your pipes. It is common for air to get trapped within your piping, which can cause reduced flow and patches of the floor which aren't as warm, ultimately decreasing the system's heat output.

Why does my underfloor heating feel cold?

If this is the first time you've had underfloor heating, you may wonder why your floor doesn't feel hot. Don't panic, your floor won't feel anywhere near as hot as traditional radiator but that doesn't mean it isn't heating your room.

What is the best thermostat setting for radiant heat?

Radiant Heat Systems

Since these systems radiate heat more gradually, they often perform best at slightly lower temperatures. Setting your thermostat to around 65°F during the day and reducing it by 5-10°F at night can optimize energy use without sacrificing comfort.

How do I increase the temperature of my underfloor heating?

However, for underfloor heating, the heat output can be significantly increased by insulating the area directly beneath the underfloor heating system. To keep running costs and heat output to a minimum, insulation offers the best possible solution.

Is it cheaper to leave underfloor heating on all the time?

Basically, your home will heat up to a comfortable temperature faster. So, whilst it won't necessarily be cheaper to leave your underfloor heating on for a sustained period initially, it could lead to long-term savings.

Why won't my underfloor heating heat up?

If your underfloor heating is not heating up and there is no sign of life on the thermostat then you need to check the electrical supply. One of the most common reasons for electric underfloor heating not working is that somebody has switched off the fused spur that supplies the underfloor heating with power!

Should underfloor heating be warm to touch?

While it's true that underfloor heating does not produce as much heat as a conventional radiator, it does generate enough heat to create a comfortable environment. The system works to evenly distribute heat over the entire floor surface, so the room temperature can reach up to 25°C.

How to reset a thermostat?

Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.

Why is my heated floor not reaching set temperature?

Heat loss in the subfloor or the space below causes floors to heat up more slowly. A slower heating time takes longer to reach the target temperature. This is due to your heating system being installed over a concrete slab or an unheated space without insulation boards.

How many hours a day should underfloor heating be on?

You can rest assured that leaving an underfloor heating system on all day long without causing any unwanted problems or damage to the system.

How long does radiant floor heating take to warm up?

Most radiant floor heat systems take about a day to come up to full temperature. The reason for this is due to how the radiant heating system stores energy. Before a radiant floor can emit energy (heat) into a space, it first has to raise the floor temperature.

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