What you call a hydronic under floor heating can be a very good system if done properly. It is called low temperature underfloor water heating where I live and pretty much everyone puts them in newly built houses. Here usually there is a panel on every floor with mixing valves that set water temperature for the floor and flow on a per room basis. I can see however how it can be bad trying to heat up an older less well insulated house.
My underfloor water heating is powered by a wood pellet burner. The house is very well insulated so the burner is off May till late October. The burner has an outside temperature sensor and since it was initially set I haven't really had to mess with the settings beyond testing how to change it. The temperature in the house is pretty much constant 21C or 69F during the heating season. If I want to change it the response time is around 1-2 hours so although I don't use those settings one can imagine programming it for 5 degrees lower when you're at work and for it to bring up the temperature to the normal setting before you arrive.
As for the cost, I have a rather small 3 bedroom detached house (110 sq.meters or 1185 sq.feet), I live in a climate where we have -20deg.C winters (eastern Europe) on top of a rather windy hill, and I pay around 460 Eur per year for the fuel for the burner. I usually burn 2.5 tons of it. This is only to heat the house. Water heating for shower use etc uses electric on demand heating. Compare this to when I was living in a city in the north of UK, so much milder climate, in a 2 bedroom semi-detached house smaller than my current house with typical central heating (or what is called hydronic heating here) using gas fired burner. I would pay around 700-800GBP so almost 900EUR per year of heating so almost exactly double. I realise I'm comparing here two houses built 50 years from each other, but the UK climate is much milder and the older house is only semi detached. This should work in its favour. Still I spend half of what I used to.
My underfloor water heating is powered by a wood pellet burner. The house is very well insulated so the burner is off May till late October. The burner has an outside temperature sensor and since it was initially set I haven't really had to mess with the settings beyond testing how to change it. The temperature in the house is pretty much constant 21C or 69F during the heating season. If I want to change it the response time is around 1-2 hours so although I don't use those settings one can imagine programming it for 5 degrees lower when you're at work and for it to bring up the temperature to the normal setting before you arrive.
As for the cost, I have a rather small 3 bedroom detached house (110 sq.meters or 1185 sq.feet), I live in a climate where we have -20deg.C winters (eastern Europe) on top of a rather windy hill, and I pay around 460 Eur per year for the fuel for the burner. I usually burn 2.5 tons of it. This is only to heat the house. Water heating for shower use etc uses electric on demand heating. Compare this to when I was living in a city in the north of UK, so much milder climate, in a 2 bedroom semi-detached house smaller than my current house with typical central heating (or what is called hydronic heating here) using gas fired burner. I would pay around 700-800GBP so almost 900EUR per year of heating so almost exactly double. I realise I'm comparing here two houses built 50 years from each other, but the UK climate is much milder and the older house is only semi detached. This should work in its favour. Still I spend half of what I used to.