Sterling Petite 7 radiators vs. Runtal radiators

VTKNH

Just had a very frustrating conversation with the plumber who is a subcontractor on our house renovations. We have 50 feet of run-down crappy looking slant fin radiators through-out ground floor of 1800 sq ft house. We're doing work to tighten up the house, but the basement is already spray-foamed and there's a 2 year old IBC propane boiler in the basement. I want the heating to be as efficient as possible. As it is, the boiler is set to heat the water to 180F, given the slant fin radiators.

I was asking about Runtal radiators since my understanding is that they are more efficient - they can heat the same space with the same linear footage of radiator with lower temp water. He kept saying all radiators are the same. I won't go into the details of the discussion, but I finally did say, "energy efficiency matters, and just because two different lines of radiator will heat a house to a certain temperature does not mean the performance is the same."

The upshot is that while I think he does know plumbing and code, etc., I don't trust him when it comes to getting performance information. He is going to give us quotes on what it would cost to install all new Petite 7s vs. the work it would take (new piping and flow valves, etc) to convert to Runtals.

Can anyone tell me anything about Sterling Petite 7s? I have looked for reviews and haven't found any. We're not made of money, so I doubt we'll wind up going with the Runtals, but I'd like to make sure that what we do use is the best we can afford.

mattmia2

If the emitters are designed for lower water temps a modcon boiler becomes more efficient. setting up outdoor reset on the modcon will also help a lot. You usually need a whole lot of fin tube to get the needed output at lower water temps.

The first step is to do a heat loss calculation so you know what the output needs to be. European panel radiators are generally a lot more of a cost effective way to get the surface area for low water temps than Runtal radiators.

GW

Hate to say it- that was me many many years ago- very limited knowledge. The plumber is not a heating specialist, or, he would have had a more sophisticated conversation with you. The good news is, he may be cheap 😬. 

Petite is the cheap stuff, it’s just normal fin tube baseboard ( I type bb). It’s the lowest end of the hot water based heating systems. I kinda prefer the KomPac bb, I simply think it looks better. Petite is a little too squatty for me. 

You may also wish to look at European panel radiators, in my opinion more popular than Runtal baseboard. 

You will pay triple or more for a European low/medium temp system. Bb is so cheap especially if the piping is already in place 

EBEBRATT-Ed

As @mattmia2 mentioned

The right way to figure this is first to do a heat loss of the house. Sounds like your plumber may not be capable of this. You can do your own heat loss by downloading the Slant Fin app.

Once that is done and you know the total heat loss of the house and each individual room you figure out how much baseboard to use. How? Download the MFG. specs for what you want to install. For instance if your heat loss is 100,000 BTUs and you use fin tube baseboard (not much difference between MFgs) yo will find that with 180 degree water you will get about 550btus/foot of baseboard

so 100,000 btus/550=182 feet of baseboard

If you wanted to use 160 degree water you would have to find the baseboard rating at that water temp.

There is a little more to it than that. You have to know the average water temp.

But bottom line is a correct heat loss

The lower water temp you run the lower your fuel cost BUT you have to install more baseboard to heat your home and more labor to install it. So it is a trade off. Maximum savings comes from return water at the boiler below 130 deg.

Radiator calculations are done the same way

And I agree with @GW If you use baseboard quality is all about the same but I wold use Sterling Kom Pak instead of Sterling Petite (unless there is a height issue with electrical outlets etc)

kcopp

Another more cost effective option would be to use the same amount of Sterling Petite 9 instead of the 7. The heat output per foot id much greater. Then you are able to a lower water temperature and be more efficient.
Heatloss is the only way to know for sure but I am guessing 150F may suffice.

Is the current IBC boiler set up to run off of outdoor temperature reset? Or does it just run at 180F all the time?

kcopp

@VTKNH What ever happened w/ this?