kwlf wrote:
water for the latter is recirculated and has anti corrosion additives added, so the pipes don’t fur and corrode to the same extent
It’s also unpressurized. The pump is a circulation pump and the max pressure is hardly above 1 atm (unless there are several floors of course). My wife’s old house had water heating in all rooms with radiators. I always had to vent/pressurize the system, because it got filled up with air. Air was leaking into the system rather than water out of it. Although to this day I still wonder where the water the air replaced went 
It used tap water, and there was a accumulator that had to be pressurized before venting, then pressurized again after. It was rather ancient, and the furnace was a combined wood/oil thing, a huge beast The only sensible thing would be to replace the whole thing with an electric heater, and keep the radiators, but she moved to my house instead.
Silvaire wrote:
Electrically heated ceiling panels were a fashion in the 70s and 80s, super cheap to install, no maintenance, but its practical only if you hardly use the heat – the monthly cost is outrageous otherwise.
Depends on the cost of electricity. Those things were popular here as well. Nowadays they are used mostly outdoor, they radiate heat rather than convect, so they work just fine on the veranda. The thing with electric heating, is it makes no difference how you do it inside a house. It’s the insulation that decides how much electricity you use. The only difference is how evenly it can be done, as well as the “feel”. Waterborne heating feels softer and usually more evenly spread. The same thing can be done with more direct use of electricity, but it requires some more thought than simply setting up an oven or two. Lots of people changed to LED for the sole purpose of using less electricity. What they didn’t get was that the old light bulbs radiated lots of heat which also heated the house
Heating is rather fascinating. Old wooden fireplaces and open fireplaces have an efficiency of about 30%. New ones have an efficiency of 85% This is done with various techniques such as afterburning, closed loop ventilation, air jets to keep the glass clean etc. It’s really rather advanced. Nothing of it is visible, the fireplaces looks like any other fireplace.
Silvaire wrote:
I’ve never needed to do repairs on air ducts in any house I’ve owned, but I’ve fixed a lot of corroded water pipes.
I’ve never had to fix any water pipes in any house I’ve own. So what does that (or your anecdotes) prove?
That is very unusual. It proves that Swedish plumbers are perfect Or maybe it is a different technique? Copper plumbing is very good (even better if one is using the pre-soldered fittings; the trade doesn’t use them much because they cost a lot more) but no matter how careful one is (I’ve done a huge amount of heating installation work myself) one gets the occassional leak. In new builds we have seen copper replaced with plastic, which is much faster to install (uses o-ring seals which should last for ever but obviously won’t) but overall the reliability is surprisingly good.
The main issues with underfloor heating are general accessibility for fixing leaks and corrosion of pipes buried in concrete/screed. Here, most installers are cowboys – always have been – and will be long gone by the time anything surfaces. There are 3 houses next to us, built in the 1980s, which all had buried pipes, and all had to be abandoned, or ripped up and replaced, because the cowboy buried copper direct in concrete and the acid ate through them. Such pipes are supposed to be plastic coated.
In the 80’s and early 90’s copper prices were very high so copper piping used in plumbing was not of the best quality, so now many people who had copper piping done in that era are now having problems.
The big advantage of plastic piping is that it can be laid underfloor in a conduit, as one piece so that if there is a problem it can be pulled through with the new piece attached at the other end and therefore no need to dig up or take up the flooring. When used in a geothermal system a gas (as in a fridge or freezer) in the pipes is used for heat transfer rather than air or water.
Peter wrote:
That is very unusual. It proves that Swedish plumbers are perfect Or maybe it is a different technique?
My point was simply that you can’t generalise from one person’s experience – Swedish or American.
Regarding technique, I have no idea what’s used in the US. In my house most of the older piping is soldered. Newer piping typically use a fitting which I have no idea what it’s called in English. A literal translation from the Swedish would be “squeeze-ring connection”. A copper ring is placed over the pipe. The ring is then deformed by the tightening of a nut and this makes a sealed connection.
That’s a compression fitting, and the bit which gets squeezed is called an olive.
In the systems I know, these are not avoidable and are used widely. They need great care in assembly but if done right they approach the reliability of soldered joints. Still, IME, most leaks are in compression fittings…
A copper heating system with no leaks, over decades, would be extraordinary. So underfloor heating can’t use any joints that I’ve ever seen. The pipes have to be one piece, but I don’t think that’s a problem because the ones I have seen are plastic which you can get in almost any length.
I think in the UK it is called a compression joint.
In France it is known as an olive, bit I couldn’t tell you if that is the real name for it.
Peter wrote:
A copper heating system with no leaks, over decades, would be extraordinary.
Well… The newer part of my house – an extension built in 1979 – has a radiator heating system (not underfloor) with copper piping. I’ve owned the house since 2006 and have not had to replace or repair any of the piping. Maybe I’ve been in luck or the previous owner made lots of repairs just before I bought the house…
You’ve been lucky, I reckon. But it is possible; when I think of how many joints I have made since the 1960s, and how many have leaked, it is well possible to get zero leaks in a single system over say 20-30 years.
Is anyone here heating their house with a heat pump?
Peter wrote:
and I’d like to know what product could be used to do underfloor heating on that, because (a) these floors are a bit flexible and (b) there is a lot of wiring and plumbing in the void (c. 20cm) under the floor so access is required, and individual floorboards can be lifted up. In some situations where a much stiffer floor was needed (generally, where you are putting down ceramic tiles e.g. expensive kitchens, or expensive bathrooms) one puts 1-2 layers of chipboard on these floorboards to produce a stiff floor but then there is no way to get inside it for access.
Infracable works perfectly. We built our house in 2007 (massive wooden chalet at 1000m/3000ft) altitude in the French Alps, house is always toasty. Downstairs we have tiled the floors (cleaner) and upstairs is parquet. We have Airco with reverse pumps (so it can heat as well if needed) but have never had to put that on. Unlike gas you obviously don’t with on the heating and have a warm house in 5 mins, but we just set the thermostat and as soon as things go below 21 deg downstairs (in winter, don’t bother in Summer with heating tbh) the thing goes on. Electricity is cheap here so all good.
