Radiant heat with oil? Can it be done?

nasadowsk · September 8

So, here's the situation - I live out in (semi) rural PA. Needless to say, no gas in the street. My (new to me) house has oil - a Crown, about 15 years or so old. Currently, the heat is via hot water baseboard. Boiler control is a Resideo electronic, flamethrower is a Becket of some sort. Nothing fancy. Two zones. Domestic water was a coil, but now is a heat pump hot water heater. Propane exists for the stove.

The front walkway is being done, and snow melt piping will be put in fr future snow melt implementation.

But that got me thinking - can I do radiant heat in the house with an oil system? The boiler still has life, but I've not heard of anyone doing radiant (or snowmelt) with oil. Radiant has a few advantages for me - my kitchen has basically no room for radiators, and most of the other rooms fall short, too. The house sits over a concrete floor basement, so installation access is ideal.

Anyone ever seen radiant/snowmelt with oil? I know radiant is lower temperature, which seems to be something a conventional oil boiler may not like, and I've never heard of a modulating condensing oil boiler. Should I look into going propane next summer? Would hate to ditch a boiler with life in it (and it's in good shape, too)

Thanks!

EBEBRATT-Ed · September 8

Of course you can do radiant with oil. Your heating water the fuel does not matter. You can heat water wit electric, natural gas, propane oil or solar.

You just need an installer who knows how to do it and you need the right equipment pump, mixing valve and the know how to pipe it right.

hot_rod · September 8

Sure, any heat source can be used for hydronic radiant.

Be aware that snowmelt takes a lot of boiler capacity. The boiler you have may not have the capacity to heat and melt snow.

It may be wise to have a dedicated boiler for the SIM (snow ice melt)

Steamhead · September 8

@nasadowsk , where in semi-rural PA are you located? We might know someone………..

If radiant is a no-go for whatever reason, my second choice would be cast-iron baseboard. It transmits heat by radiation as well as convection, increasing comfort.

GroundUp · September 8

Absolutely- as long as it's properly piped and controlled. It's not as simple as just piping the radiant in and out of the oil boiler due to the minimum 140* return for any non-condensing boiler, so it often requires a primary/secondary piping arrangement with a mixing device for the radiant only. Snowmelt would generally require a heat exchanger to allow the outdoor system to use glycol without filling the whole indoor system as well. There are quite a few needs to do this properly, but there is nothing stopping an oil boiler from heating a radiant system.

RascalOrnery · September 8

I use anthracite coal for radiant, it's a great match. I wouldn't want to pay to melt sidewalks with oil though. Sheesh. I pay the equivalent to 88 cents a gallon when comparing btu to BTU. And it would be expensive even for me. It's like three to five times the heat requirement compared to your house per square foot. I can see a very small pad maybe, there are also different classes of snow melt systems, those which keep it dry take a lot of BTUs. Great questions, keep them coming.

Radiant can be more efficient since your system temps can be a lot lower. You may have to run through a mixing valve if you still want to run the baseboards at full temp, the fact you don't have a tank less coil could greatly enable you to keep system temps lower.

EdTheHeaterMan · September 8

@nasadowsk said: "Domestic water was a coil, but now is a heat pump hot water heater."

I believe this to mean that the oil fired boiler was/is equipped with tankless coil. Many of my customers have had heaters like this and have switched the DHW to gas. electric or other DHW source. Out of all those customers, only a small percentage of the plumbers that installed the new DHW system knew to fix the tankless coil control on the oil fired boiler system to stop making priority hot water for a coil that is not being used. YES I'm saying the the oil fired boiler thinks it is still making DHW and will waste fuel trying to make hot water that will never be used.

If this is the case with your oil fired Crown boiler, then I can save you about 5% to 10% on your fuel usage by making some minor adjustments on the oil burner control that is currently operating your oil burner and circulator pump(s). Ask me how!

nasadowsk · September 8

Ok - more info:

Yes! I did in fact adjust the boiler's controls when the old coil was taken out of service. That's when the Resideo electronic unit went in. It's set purely for heating, no temperature maintaining. Oil use sure dropped a bit. The local oil guy did a service, and that helped too. Unit hadn't been cleaned in 4 years.

The walkway is short - but annoying enough to deal with that it justifies getting melted. I'm aware of the need for a heat exchanger and antifreeze. Since it's being formed out, I figured the cost of at least prepping it for heat now, is low enough to justify just putting the pipes in. It's a 3 ft wide, 20ft (if that) long, with a bit of a square spot by the patio. Obviously not running all the time, just for snow. I think I have a Watts book on design guidelines here somewhere.

I expect to do the family room first (virtually no electric wiring under it, so easy access, and easy to get insulation under the piping.) then changeover the rest of the house. The boiler is oversized, and even with a smaller nozzle, tends to run shorter cycles than what I think is ideal. (it fires maybe 3-5 minutes while running and pumps the rest of the time). This got a bit worse after I started insulating all the basement pipes. Nothing had insulation on it. The prior homeowner tried to 'help' the kitchen's lack of heat by putting a run of baseboard under the floor. 🙄

FWIW, I'm just outside of Catawissa, PA. The previous owner of the property was apparently somewhat well known, and quite a character, from the stories I've heard…

hot_rod · September 9

call it 100 sq feet of snow melt? A basic class 1 is about 100 btu/ sq ft, so the snowmelt, when running could use 100.000 btu/hr

What size boiler?

The more btu you can afford the snowmelt , the quicker it melts, 100 btu/ ft is on the low end. If you get a big dump, you may need to break out the shovel🤭

GroundUp · September 9

100BTU X 100SF = 10,000 BTU. Just to clarify

Steamhead · September 9

@nasadowsk said:

"FWIW, I'm just outside of Catawissa, PA. The previous owner of the property was apparently somewhat well known, and quite a character, from the stories I've heard…"

Was he in the oilheat business? If so, I think I know who you mean…………….

nasadowsk · September 9

Nah, he wasn't. He was an electrician. The guys who did the air conditioning in here are a well established firm in the area, and did a really nice job, though I don't think many central A/C systems in homes out here are zoned.

(I'm still trying to figure out what 1/2 the light switches in this place do…)

My oil guy is just south on 42 in Numedia.

HydronicMike · September 9

For radiant, and especially oil, (along with multiple zones) you’ll need a buffer tank.
And of course proper design.

Bruce MacNeil · September 18

For sure. Ideally a heat pump in this situation would be marvelous. The lower temperature of the radiant makes a heat pump very attractive.

HydronicMike · September 19

@GroundUp why do you disagree?

GroundUp · September 20

https://forum.heatinghelp.com/discussion/comment/1865386#Comment_1865386

Because he absolutely does not "need" a buffer tank. If there are a bunch of micro zones, he could USE a buffer tank to help with cycling, but to say he NEEDS one with only the information we have is ridiculous.

HydronicMike · September 20

Well you must not do much oil with hydronics then.
With the exception of a properly sized oil boiler running on design day, the rest of the time it is oversized.

Add any kind of zoning and especially with outdoor reset, and it’s extremely oversized the rest of the year. The result is constant short cycling.
Therefore, a buffer tank is always recommended.
Even worse if you’re using it for snow melt. Because you should not even think about running super cold water return with glycol threw a boiler.

I’m only interested in giving the best advice. But feel free to do things incorrectly as much as you like.

GroundUp · September 20

https://forum.heatinghelp.com/discussion/comment/1865501#Comment_1865501

It's a block of cast iron, just like its gas counterpart. It has the thermal mass that it needs to go 30+ years built in. Basic primary/secondary piping or even the cheap bypass as shown in most install manuals prevent the cold return water issue you describe, so a buffer tank is a complete waste of resources in 99% of cases. If you're actually interested in giving the best advice, stick around and learn the trade before spouting off about something you don't understand.

Radiant heat with oil? Can it be done?

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