Would this work ?

dyrniboy

Hi, I am thinking of replacing my 18 year old oil boiler with a new combi. I was also thinking of buying some Underfloorheating pipe and placing it between the ceiling joists in the loft with the loft insulation covering it. The incoming water to the boiler would then flow through the ufh pipe which is spread through the loft and pick up the heat whichis trapped at ceiling height. This would pre-heat the water before it enters the boiler and would hopefully save on oil. I put a thermometer underneath loft insulation in the summer and had a reading of 27 degrees !.

All thoughts welcome !!

Newbird

Interesting! Good lateral thinking there, but you've got to buy the piping to start with so you'd have to recoup the cost against possible oil savings...We did have a warm summer this time.

gromituk

This is one of those ideas which is fine in theory but not so good in practice, I'm afraid. One reason is that the cold water coming into the house in the summer approaches 20 degrees anyway, so you'd get little gain in temperature. Another reason is that the thermal resistance between the air and the pipes would be relatively high, meaning that you'd need to have a lot of pipe in there to gain heat in still water over a long period in order to get a significant amount of energy.

PS it would be good if you could make the subject line meaningful, to save people time who have to open the discussion thread and then find it doesn't interest them. Thanks.

dyrniboy

thanx newbird & gromit uk, I just thought it might be a more cost effective method than the heat source pump you put in the garden for about £10,000.It pretty much works on the same idea. i was thinking in the winter the central heating would be on and the trapped heat at ceiling height could pre-heat the water to the boiler or even the electric shower. Priced the underfloor heating pipe at about £350 for 200 metres.

gromituk

Cooling the ceiling down in winter will only lead to an increase in your heating bills, unfortunately. It's like removing your loft insulation.

dyrniboy

Thanx Gromituk,

Ahhh well, back to the drawing board !!!