Can wet system piping be run through old warm air ducts

[TanDiy]

Hi, We are about to change warm air to a wet system. We have had a couple of independent engineers in to cost the job and they have both said they need to run surface pipes downstairs due to concrete floors. One has also said that he will use plastic pipes upstairs and this is quite common now?

I was wondering if the existing downstairs warm air ducts could be used to run the pipework - is there some sort of flexible hosing or something that could be used. I am thinking about this because there are warm air ducts just a few inches from the wall in the exact place that we would need each radiator. I am thinking that we could cut a small trench in the floor from the warm air duct for the pipework to run to the wall. We could then make good the vent and the duct with the piping appearing as if it had come from the floor.

We would be most grateful for any advice and guidance on this. Also, is it correct that upstairs piping could be run in plastic - surelly soldered copper would provide more reliable? Thank you.

 

[flameport]

Plastic pipes are used because they are cheaper than copper, and generally much quicker to install. Nothing wrong with them provided they are installed properly.

As for the ducts - impossible to say without seeing it, however your 'flexible hosing' would be plastic pipe, which isn't actually as flexible as you might think.

 

[FiremanT]

I would be wary of noise transmission through the ducts.

 

[TanDiy]

Many thanks for the advice - yes I did not think about noise in the ducts.

 

[swbjackson]

I've done this in the past. To prevent noise transmission I lagged the pipes as I fed them in. Worked very well.