I have hydronic slab heating which I installed when I built our house around 18 years ago. It is a really gently pleasant heat with no hot spots. However, it take a long time to heat up (and cool down), sometimes as long as 4 to 6 hours! In autumn and spring when the weather is variable it is difficult to keep the house at a comfortable temperature.
If I were putting in slab heating again I would install slab heating to the tiled areas and supplement it with wall panels to provide quick direct heating instead (or maybe even in addition to whole of slab heating). This would give you a fast response to sudden cold snaps while provide the pleasant background heating. It is also very comforting to be able to stand around a very warm spot for a while when coming in from the cold.
If you are thinking of using solar thermal panels as significant source of heating then definitely go for whole of house heating. It is the only practical way of getting the thermal storage to make best use of the solar. Using a tank to provide the storage for wall panels will not be effective unless you have a really massive, insulated tank (well in excess of 10,000 litres and preferably a minimum of 20,000 litres).
If you are going to use electric or gas hydronic then it may make more sense to go for the hybrid heating solution.
The water circulating through the slab is limited to a maximum temperature of 50 degrees. This is primarily to protect the (plastic) pipework but does reduce the stress on the slab and help prevent it from becoming too hot especially where multiple pipes route under doorways.
If you are going to use a heat pump, and you are able to do the earthworks, it might be worthwhile to consider a ground sourced heat, pump where pipes are buried in the ground at 1 metre to 2 metres deep to take advantage of the milder temperature below ground. However, this may be too expensive to offset the lower operating costs.
If you have designed (and built) the house well, with very good passive design principles then the heating ( and cooling) requirements should be minimal and that will ease the design constraints on whatever heating you choose.
One last thing about slab heats heating, for all it's disadvantages, when you stumble into the bathroom, half asleep, at 3:00am, it is such a wonderful feeling to step on a warm tiled floor
Cheers
Posted Monday 13 May 2013 @ 1:50:39 pm from IP
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