Opinion please.....add radiators vs under-floor radiant pex tubing. Cost effectiveness is priority.

[Huskurdu]

I currently have b/b hyrdronic and would like to take advantage of lower boiler/storage (~500 gal.) water temps to heat my house. I'm thinking of splicing some old time radiators in series with b/b or maybe using the wood boiler return line (from the house back to the wood boiler) to do some underfloor pex tubing. Any thoughts would be appreciated.

 

[Singed Eyebrows]

Over 20 years ago I put in large under window cast iron radiators & couldn't be happier with them. I could heat with approx 110 degree water(continuous flow) down to probably 30 degrees with them. My thoughts are, forget about the baseboard & put in the rads. Like Eric Johnson said, this is like having a cast iron stove in the room. Don't buy the steam rads though, these are typically rounded on the top with about 3 tubes(don't confuse tubes with sections). Hot water rads have more tubes, mine have 7 or 8 & are squared off on the top. Good luck, Randy

 

[Jeff S]

I installed cast iron radiator last year and was very happy with the results,this year I have added a Tekmar boiler control with outdoor reset and variable injection so I too could take advantage of the lower temperatures.last winter I rarely used water over 130* with the Tekmar I will be using Temps between 80 - 130* depending on the outdoor temp..

As far as putting radiators in series with fin tube it is usually not recommended,rads have a much larger water capacity and take longer to heat up and cool down and that is were you get that more even heat effect were as fin-tube is much more responsive and is considered a more harsh heat.

 

[tom in maine]

My previous house had big old radiators. I changed over the plumbing to PEX and installed thermostatic control valves on each
radiator. It operated with an outdoor reset controller and had no room thermostat anywhere in the house since each radiator was
operating most of the time with constant circulation.

It was very very comfortable and was a lot more convenient to install. If you have access to the rads, I think it is a great way to go.
You can usually find a deal on the thermostatic valves on Ebay.
It should cost a fair bit less than a complete radiant system.

 

[btuser]

Baseboards are cheap. Look cheap, are cheap, take up wall space. If I had my choice it would be the old ornate CI radiators. if you notice the casting there is a ton of surface area on them, much better than the steel ones which are smooth. I think this is the main advantage to them.

Radiant is great depending on your floors/building mass. I recently saw a retro-radiant system in a 2 story house where they ran soffits for central air down both exterior walls on the first floor, which gave them registers for the first floor and then floor registers on the 2nd. They then used the access these provided to pull loops of pex for radiant heating through the joists spaces, and sprayfoamed the sill plates. The plan was to heat the middle of the house/floors and let the heat radiate out. The same thing was done in the basement.