Find out what hydronic heating is and learn how it works. Learn what its benefits are over furnace heat and how it is different from traditional steam heat.
LESLIE: Well, you may not know this but hot-water heating has been very popular for a long, long time and I mean a really long time, because it was first invented by the ancient Romans.
And Richard, it might be a little more comfortable to install but you really can’t beat the natural comfort of a hot-water system. Did the Romans have it right?
RICHARD: They did but you can’t get a Roman nowadays. You have to call a decent, hydronic heating  contractor.
So first, a little bit of definition. Hydronic has some components. One is a heating boiler and that’s going to be gas or oil; it could even be electric. And you’re going to heat the water and then it has to be circulated, so there’s some sort of circulator pump to push that water through piping.
And then you need some way to release the heat to the rooms or individual areas and that could be radiant, it could be baseboard, it could be radiators, it could be some of these beautiful towel warmers that you see everywhere.
But it even could be a thing called "hydro-air," where you could be sending water up to a hot-water heating coil that would sit inside of duct work. And air would blow across it from the room and get heated by that water that originated down at the heating boiler.
TOM: Now can you get enough heat out of the boiler to do that? Because it would seem that the water temperature, I guess, inside a system like that, is it hotter than it would be in a traditional radiator?
RICHARD: It can change and that’s another great thing about hydronic is that any decent hydronic system would also have a control on it to know how cold it is outside. So the boiler would make the water really, really warm or hot on a cold, cold day.
But on a mild day, it would just be mild temperature. Now you’re going to have real comfort because it’s not going to be – people often complain about a furnace; that it’s on and it’s hot and then it shuts off and you’re cold.
RICHARD: And with hydronic, you’ll be much more comfortable through the building.
TOM: There’s just so much more moisture in the air and that moisture really holds the heat, which is the reason that hot air is just not as effective.
RICHARD: That’s right. Right.
TOM: Not to mention the fact that first of all, you heat the air, then you have to remoisten the air.
RICHARD: That’s right.
TOM: There’s a lot of energy that goes into trying to make it comfortable.
LESLIE: Now, how different is it from traditional steam heat ? Our house is almost 100 years old. Tom has a hundred-year-old house. We have radiators, we’ve got steam heat and we love it and it’s comfortable but with the new hydronic, are the radiators as large?
LESLIE: What’s the difference?
RICHARD: Steam is not really hydronic; steam is a little bit different. Even though you have radiators and you think that it’s hydronic heating, it has some water down in the boiler, right? There’s one thermostat in the house and the thermostat comes on and that burner comes on and heats up that water and turns it to steam. So every radiator gets the same temperature at the same time, so you can’t zone it. You hear the radiators hiss and everything else.
With hydronic, it’s quiet. It can be zoned. You can have a variety of heating sources: you can have baseboard, you can have radiators, you can have these beautiful, towel-warmer radiators that you can’t have with …
LESLIE: All connected to the same system.
LESLIE: That’s amazing.
RICHARD: And just – and you circulate warm water.
The other sort of untold story about hydronic heating is that as fuel prices start to go up – gas and oil – alternative energies are going to have to become the way that we do it: with geothermal, with solar, with all sorts of air-to-water heat pumps.
So if you have a water-based system, you can actually collect that energy and distribute it through the building. If you have a hot-air system, you can’t.
TOM: Well, it used to be the only way to distribute a hot-water system was through a hard, metal pipe; either steel or copper. But now we have PEX and that is so much easier to work with.
TOM: That’s got to make it more attractive, as well.
RICHARD: That really is the breakthrough, I think; this sort of super-plastic that you could run and fish like the electrician might run wire. And now you could zone every room easily. You could have a dedicated supply and return; every room could have a different type of radiation in it to deliver heat to the building. I think that’s really the breakthrough.
LESLIE: And PEX is really easy for you guys to work with. You can make repairs while the entire system is running, based on these new, sort of connect-air (ph) systems, correct?
RICHARD: Right. And there’s no soldering inside the walls; there’s very few fittings. You’re actually just running from Point A to Point B and you’re running it, like I said, much like the electrician runs wire.
TOM: Far more durable, really, than the metal pipe.
RICHARD: It doesn’t rust.
TOM: It doesn’t rust. Good point. Richard Tretheway from TV’s This Old House, great advice that’s going to make us so much more comfortable this winter. Thanks so much for stopping by The Money Pit.
RICHARD: Glad to be here.
LESLIE: Alright. You can watch Richard and the entire This Old House team on This Old House and Ask This Old House, on your local PBS station.
TOM: And This Old House and Ask This Old House are brought to you by GMC. GMC, we are professional grade.