Radiators vs Baseboards

[trehugr]

I am planning to plumb the basement family rm and utility rm for heat. Are cast iron radiators more efficient than baseboards. Do they require the same temps as baseboards ?

 

[tuolumne]

Are you referring to older used ones? I am no expert, but looked into many radiators recently. I'll assume new baseboards versus new wall radiators. Baseboards are the cheapest by a good margin, up front that is. I know our kids (5 at 6 and under) trashed the baseboards in our previous home. Most baseboard heat is designed for 180 deg water, so I avoided them in the home we're building since I want to run my buffer tanks down to lower temperatures. Wall panel radiators can also run the high temperatures, but have more heat transfer surface internally and can run down to lower temperatures. If you design them for lower temperatures, you'll need more are larger panels. I looked at Biasi, Buderus and Myson wall panels which all spec out and look similar. I also looked at Runtal products which look different, are very rugged, but a lot more expensive than the wall panels. A typcal bedroom in the home we're building has a heat loss of 3,000 btu/hr and required a 22x48 wall panel with a supply temperature of 140 degrees. When it's not 20 below zero, I should be able to run my buffer tanks down even lower than 140. The wall panels also give me a lot of control over heat distribution. One zone upstairs has 3 bedrooms and one bathroom. A thermostat is in only one room, but diverters on the supply return let me initially balance the flows, and thermostatic heads on the radiators allow individual room control.

 

[trehugr]

Thanks for such a detailed answer. That gives me a alot to work with. Thanks

Kevin

 

[Bob Rohr]

Fin tube baseboard are considered convectors. Cooler air from the rooms floor is drawn across the fins, warmed and moved by convection currents across the room. The warmer the water the more output. Some of the baseboard manufacturers are now showing output ratings with the lower water temperatures 120F-ish, to work well with low temperature condensor boilers.

Panel radiators, the flat style type, move heat by both convection and radiation. Some air movement through the core, but also some radiant energy from the flat steel panel. Usually a much heavier steel is used to form them, they are powder coated and durable, easily zoned at each radiator, and able to work in that 120- 140f range.

Best to do a room by room heat load calculation, determine your heat source and output temperature, then match the panel size to get 'er done.

I've seen some pretty wild color and shapes in panel rads, like this staircase version.

I have also welded up some of my own with square and round tubing for a large towel bar, bathroom radiator.

And my bedframe is a copper tube radiator. Hot water flowing through some pipes is as simple as it gets.

hr

 

[Bob Rohr]

stair case radiator

 

[bbb123]

New meaning to water bed.

 

[Eric Johnson]

I've got about 15 old cast iron radiators heating my house and we love 'em. It's like having a little wood stove in every room--a good place to warm your hands and other body parts. Plus they hold heat for a long time after the pump shuts down.

I liked the copper bike frame, too, hot rod.

 

[Como]

Baseboards can operate at a lower temerature:

(broken link removed to http://www.discreteheat.co.uk/new_products.html)

 

[trehugr]

Eric, did you install them or were they already there ? Are the newer modern type more desirable efficiency wise ? I must admit, I really would rather look at something like this.

 

[sled_mack]

I have 5 old cast iron radiators in our house. They were taken from an old farm house that was being torn down. Got them for free (plus the labor). 2 of them came with sheet metal covers, painted to be a wood grain. I wasn't sure I liked that, but it matched our walls perfectly so we used them. And, we ended up buying 2 more. Supposedly, they get more heat into the room, but I don't know if I buy that. Maybe if they are right under a window?

Years later, I added infloor radiant to all of these rooms. Some zones the water goes through the radiator first, others it goes last. Even at lower temps - 120 to 140 - you get a nice warm feeling when you walk by them.

 

[mtfallsmikey]

Hey HR...going to have time do do those fancy creations after you start the new job?

 

[Eric Johnson]

Most of the rads were in the house, but I've added a few over the years to replace some baseboard, which I don't care for. I like the look and feel of the cast iron a lot better. To me, they're functional works of art. Here's a pic of an old steam-only rad that I got to work with my hot water system. This is in the kitchen. It's so nice to have that beautiful heat source in the breakfast nook. The cats love them, too.

My understanding is that you can get by with lower water temps with radiators than you can with baseboards. With all that cast iron mass and water, you're spreading it out over a much greater surface area, allowing you to get by with less.

 

[wdc1160]

Those are some sharp rads boys

 

[Eric Johnson]

Here's one I refurbed last fall and put in the greenhouse. Note the lion design.

I've only done old rads, but I doubt there's much difference (other than the price) for new ones. Around here, you can pick up old radiators for around $100 each, sometimes a lot less (like $0) for just hauling them away. You have to be careful not to drop or crack them. It's always a good idea to pressure test them before making all the effort, if possible. It's also a good idea to flush them out. Old steam rads are the worst--they usually have decades worth of rust and other crap sitting in the traps near the inlets and outlets.

If you're looking for rads for a hot water system, be sure they have a "top pipe" which is the channel connecting the columns on the top. If you look at the rad in my kitchen, you can see that there's no way to vent the air when filling it. A radiator half full of air isn't going to work very well.

My house was built around 1865, but I'm guessing that the hydronic heating system was a retrofit done around the turn of the century. Maybe I'm wrong. The people who did the various additions to the original farmhouse used cast iron radiators, which I'm grateful for, except for that unfortunate baseboard install in the kitchen. Replacing that junk with the radiators had an incredible WAF.

 

[wally]

nice looking radiators, eric. i wish i had the room, which is the downside of the radiators - they're big. baseboard takes up a lot less "room". so, in my admittedly small house, we've made do with baseboards. if i had the space, i'd really like to replace the baseboard with rads', but i don't see it happening. at least the wood is "free".

wally

 

[mack7]

So have we come to a decision on what is better? I am considering zoning out my basement and upstairs from my main floor and was also wondering which is better. I currently use a heat exchanger in my furnace to heat about 3700 sq ft, my problem is that some of my duct runs in this old house are loooonnngggg causing the main floor to be nice and toasty and the basement and upstairs a bit chilly. I have also considered putting in a couple more air handlers with heat exchangers, one for just the basement ductwork and one for just the upstairs duct runs. I appreciate any suggestions from others with experience. Thanks guys

 

[Eric Johnson]

As Wally suggested, if you have the room and you (or perhaps more importantly, your wife) consider them appropriate, cast iron radiators are better than baseboard for heating a given space, plus you can get by with cooler water. That's my opinion, having used both and discussed the issue with heating professionals. Infloor radiant beats them both by a wide margin.

I'd be a little leery of air handlers. As discussed in another recent thread, they apparently put different demands on a wood-fired hydronic heating system that can throw things out of whack.

https://www.hearth.com/talk/threads/14748/