Lay underfloor heating by routing into concrete floor?

ComicGeek

knightstyle said:

You must find out why this room is so cold in winter.  Check insulation in the ceiling and walls, it is far better to improve insulation than to install expensive underfloor heating.
Remember that a perfectly insulated room needs no extra heating, just the heat given off by our bodies and things like light fittings.

Not really - heat demand is a combination of heat loss through fabric and heat loss via ventilation. With modern houses there can be more heat loss via infiltration and ventilation than from fabric losses. So insulation is important, but increasingly more important to deal with air infiltration. 

grumbler

ComicGeek said:

With modern houses there can be more heat loss via infiltration and ventilation than from fabric losses. So insulation is important, but increasingly more important to deal with air infiltration. 

What makes modern houses special in terms of infiltration?

With regard to ventilation, I think all houses are pretty much the same and the only difference can be made by using a heat recovery ventilation system.

ComicGeek

grumbler said:

ComicGeek said:

With modern houses there can be more heat loss via infiltration and ventilation than from fabric losses. So insulation is important, but increasingly more important to deal with air infiltration. 

What makes modern houses special in terms of infiltration?

With regard to ventilation, I think all houses are pretty much the same and the only difference can be made by using a heat recovery ventilation system.

Not special - just that improvements in insulation standards haven't been matched by improvements in air tightness. So while the fabric heat loss has been reducing steadily, the same can't be said of air infiltration losses - particularly in extensions where air testing isn't required.

All houses are definitely not the same. I had my 1990 build house air tested recently as I wanted to understand where the problems were and improve them, and it was 4 times that of a typical new build house. An older house with solid brick walls and single glazing could be even higher. We're not just talking about 'controlled' ventilation in terms of trickle vents (as I don't have any), it's uncontrolled air leakage around windows, through downlighting, around skirting boards, loft hatches, service penetrations etc. Not all of that can be resolved by mechanical ventilation.

FreeBear

ComicGeek said: All houses are definitely not the same.

We're not just talking about 'controlled' ventilation in terms of trickle vents (as I don't have any), it's uncontrolled air leakage around windows, through downlighting, around skirting boards, loft hatches, service penetrations etc.

Replaced some of the windows here, and I was horrified at the gaps left when they were originally fitted back in the 1970s. I was always aware of a draught coming in "somewhere" around one of the windows, and I now know why. A ruddy great gap had been left across the top... Three more windows to do, and this place should be a lot warmer.

Mutton_Geoff

Don't forget with a wet UFH system, you'll also need a manifold, pump and separate controls adding to the cost.