House Heat up time

[Barryscotland]

For a bungalow 160m2 that’s sitting at 17 degrees throughout with little heat in the screed as the heatings not been on for a few days how long would you expect the ufh to be on for to reach 21 degrees throughout?

[jayc89]

It massively depends on your set up, how well balanced it is (flow rate/temp etc). In general, I'd expect my UFH to get up to temp in around 3 hours from a cold start.

[JohnMo]

A few things affect warm up time. So answers could be correct but only approx.  Anything from 3 to 6 hours is best guess.

 

1.  UFH pipe spacing, 150mm is quicker than 300mm; which can be quite slow.

 

2. Flow temperature, the higher the temperature, the quicker the heat up time, but much more likely to overshoot the thermostat set point.

 

3. Amount of insulation under the screed, but also the amount of insulation in the walls and roof.  More insulation should allow the most amount of heat to be transferred to the screed and room.

 

4.  Depth of screed, deep screed slow to heat up compared to shallow screed.  Deeper screed is slower to cool down.

 

Example, my house.

 

190m2, 300mm UFH spacing, 100mm thick concrete screed, 200mm PIR under screed.  U values, wall 0.14, roof 0.12, windows 0.8.

 

Flow temp 30degC, heating time generally 5 to 6 hours overnight. But the floor then retains the heat until the next overnight heating cycle.

 

[SteamyTea]

19 minutes ago, JohnMo said:

A few things affect warm up time

Air changes an hour as well (with and without heat recovery).

[JohnMo]

Missed that one

[joth]

6 hours ago, JohnMo said:

A few things affect warm up time

Outside temperature also will. And of course if there's solar gains to help it along