New Radiant System in Old House
I’m currently looking into options for ~3,000 sq ft of radiant heating for a residence in eastern PA. ~1,200 of the those sq ft will be set in concrete, over a stone filled crawlspace. I’m shopping around for the best systems to use for my installer and I. On the areas that are not concrete, the floors will be getting new subfloors, so I can really build this whichever way is the most cost effective & efficient.
The house doesn’t have the best envelope as it is a modern house with a lot of glass windows. The system currently is hydronic baseboard which is oil fired. I’ll be dropping in a propane tank for use with this heating.
I have a quote coming in from Radiantec around $ which includes their Nortiz boiler/manifolds, etc. I was wondering if people like Radiantec, or could recommend any alternatives.
Thank you
Comments
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You will not find many fans of Radiantec here on HeatingHelp for a host of reasons which will become evident.
Are you the GC? Have you ever installed a hydronic heating system? Do you have a hydronic supplier in your area?8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab
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If it has things like entire walls of glass you may need to supplement the radiant with some other type of emitter or some hydroair to cover that load.
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Alan, yes I am the GC. I have not installed a hydronic heating system myself, but I do have an independent tech who is capable. I haven’t contacted any hydronic suppliers in my area yet. Location is Bucks County, PA..
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Do your sums. Then do them again. By which I mean run a full Manual Jon that structure, particular considering the large glass areas.
Then compare the results to what you can get out a radiant floor As @mattmia2 said, you may discover that there is no way you can meet the heat loss even close to a design day, and will need supplemental heat.
For that matter, it that glass is south or even more or less south facing, you may have some real problems controlling temperatures in various rooms. Radiant heat can be zoned, although iit gets a bit tricky, but it can't respond to loads which change within a matter of hours. Days, yes. Hours, no.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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Like Jamie said above, your most important tool in designing and installing a hydronic system will be an accurate room-by-room heatloss calculation. R-values for walls, floors and ceiling insulation, window types, infiltration rates and design temperature all come into play to give you a heat load. And that heat load will tell you how large to size the radiator for that room or if you're doing radiant, how close to space your tubing and ultimately, what size boiler to install. John Siegenthaler makes an easy to use heatloss program here.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
Panel or tube radiators with steel pipe will provide the owner with much more thermal mass and the home will be warmer.
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As others have said, a radiant floor is not gonna heat an old house with a lot of glass by itself.
You need to do (or have done) an accurate Manual J load calculation. It needs to be done room by room as the amount of tubing required per square foot will vary greatly between rooms.
This is the first and most critical step in designing a radiant floor. Skip it, or cheap out on it, at your own peril.
Radiant Wreck? ☹️☹️☹️
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
how many feet of actual finned tube do you have now? Has it been heating the home adequately?
If so the footage X 500 will get you a ballpark estimate on the heat required.
If you have 80’ of fin tube, the load would be around 40,000
Now you have a ballpark load number to see if the radiant could cover the load.
If nothing else do a heat load calc for the room with all the glass. That will be the room that may need supplemental to the floor radiant
A free load calc demo here
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
I remember a builder dropping off plans for a new home that included a room measuring 20 feet wide by 30 feet deep. One entire wall was curved glass extending from floor to ceiling, approximately 26 feet tall and 20 feet wide. There was no practical location for any conventional heating equipment in that room, so he wanted to use radiant floor heating.
Back in those days, Wirsbo would take your plans, perform the heat-loss calculations, and provide a complete material list along with a tubing layout. It made it very easy for the supply house to prepare a quote for the radiant floor heating materials.
When the calculations came back, the entire home could be heated with radiant floor heating except for that 20' x 30' room with the curved glass wall. The radiant floor system maxed out at only about 40% of the design heating load on a design-day condition.
To make up the difference, I added 20 feet of Runtal curved baseboard, three panels high, controlled as Stage 2 of the thermostat. The windows would have needed to be installed about 10 inches above the floor to accommodate the baseboard heaters. That increased the available heat output to roughly 70% of the design load.
The remaining load was assigned to the fan coil for the air conditioning system. That became Stage 3 of the thermostat and would operate only when the outdoor temperature dropped below 20°F, providing the additional heat needed with a small margin to spare.
I'm not sure if the builder ever constructed the home because I left the supply house before the job was sold. However, it was a lot of fun designing the system and working out the three-stage control strategy needed to make it all operate properly.
Your Glass wall project may not me that involved, however you may need to consider additional heating over and above the floor heat. …and as Hot_rod mentioned You may already have the information you need by knowing if the existing baseboard radiators heated the room properly, unless the glass wall does not yet exist, and is part of the renovations.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Ed, what was the cooling like on that room? Or was that not your department?
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Howdy,
We manufacture RadKingPanels, a retrofit radiant heat panel that is ideal for applications like yours. The panels are secured directly to the subfloor, provide excellent heat transfer, and are designed for efficient installation.
As both manufacturers and installers of radiant floor heating systems, we have extensive real-world experience with retrofit projects and would be happy to help answer any questions about design, panel selection, or installation.
If you'd like additional information, specifications, or pricing, feel free to reach out to us at RadKingHeat@gmail.com.
Good luck with your project, and we're happy to help however we can.
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Is this a new company? I don't remember seeing this name before.
Where are you located? There's no location or phone number on your site…………….
Baltimore, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting0 -
I have done quite a few projects in bucks county. Personal … some old stone and I built a new modern as well . As others have said you need that heat load …Rome by room. That is the only way to know where you stand … you can get a bit more heat per square foot out of concrete. I like warmboard but it’s expensive .. it works and responds quickly. As others have said you can add baseboard … runtal will make anything but again .. expensive. Radiant is great … you can also plan on using whatever is for ac to add to the heat on really cold days. I have done that as well
make sure ti insulate the slab on any radiant slab0 -
The cooling was a big part of the job. I believe this home had three outdoor units: one for the upstairs rooms, one for the first-floor areas, and a separate 5-ton unit for the large room.
How do you move 5 tons of air in a 20' x 30' room without making any noise?
I performed the cooling load calculation, and Wirsbo performed the heat-loss calculation for the radiant floor system and provided the CAD drawing for the tubing layout. The HVAC contractor still needed to design the ductwork.
The radiant floor heating design was the easy part. Figuring out how to quietly deliver enough cooling air to that room was the real challenge.
At the time I was working for a supply house just selling the stuff.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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what exactly is going on in this room that it needs 5 tons of cooling? it is certainly doable, you just need a lot of big ductwork with many big inlets and outlets, probably with the architecture designed with places to hide it
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Walls of glass. When the sun goes down the load drops to 3,000 BTU/hr.
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