RADIANT HEAT WITH WL110 (long winded)

I thought I would post a new topic concerning the use of radiant heat and the WL110 as the heat source. I have had many questions about my install and it's success so I thought i woud try to help others.

House dimensions: 24 x 48 for 2 floors with 9' ceilings (2304 sqft)
Full basement with XI superior walls (R-15) (1152 sqft)
3rd story with 150+sqft un heated directly just residual to 60 degrees

TOTAL HEATED AREA INDIRECT + DIRECT = just over 3600 sqft with 9ft ceilings.

All subfloors 3/4". First floor 1/3 tile, 1/3 bamboo, 1/3 carpet.
Second floor is ALL carpet.

All carpet areas use 7/16 padding, wished it was rubber (better transfer) and i did spec rubber but was not around when the install happened and we (wife) signed off on it not knowing the difference but it is just foam (poor conductor of heat). oh well...

general rules of thumb are when using 1/2" pex no longer than 300' runs. Mine are all less than that, some are 298' others are around 270'. Typical water temp to floor (depending on floor makup) will not exceed 160degrees. My entire second floor is carpeted (most will tell you that is a no no but mine heats fine with a little higher water temp (150-160) on cold days. I used 1/2" pex because it is easier to bend than 3/4 or 7/8. Most all calcs come out to the same BTU/SQFT between different tube sizes.

I have the second story on 2 zones. One for the front of the house and 1 for the back. Each zone has 3 runs that water flow can individually be adjusted. First floor has 6 runs with individual adjustable runs.

Each floor has about 1850' of tubing

Heat transfered by radiant is directly related to water temp and water flow. Typically use 1gpm per run of tubing for 1/2"

A heat loss calc is helpful for any house but sometimes general rules can be used. I used basically a "manual j" type calc.

Transfer plates (aluminum) are in my opinion a NECESSITY!!!!. I have never seen a car without a radiator (unless aircooled in which they still have fins), therefore to me radiant should never be installed without radiant transfer plates. Radiant heat is a combination of Radiant/Conduction/Convection transfer. WIthout plates the later 2 don't work so well.

Insulation under the tubing is a must as well. Minimum of R19 in my book with a radiant barrier facing the tubing. My second floor is R-39 below tubing because I wanted sound deadening between floors. 2" airgap between insulation and tubing a must.

I used a company called BLUE RIDGE RADIANT for sourcing ALL the material (not sure if I can say that here???), if you buy the material from them they make the layout drawing for free.

Heat source (Leisureline WL110) chosen for quick response as well as 5gpm domestic hot water coil. I was told by every plumber that I spoke to (countless) that tankless coils in boilers dont work.... Hmmmmm wife takes 30 min showers with 44 degree ground water temp with ease.....

Radiant heat should be set up on a primary/secondary loop for the boiler. This keeps a desired water temp available to the boiler and keeps thermal shock to a minimum.

I do not have an outdoor reset. With this boiler I do not need to. I set the max water temp going to the manifolds with a mixing valve and let the boiler "poor the coal" to the water temp. When a zone calls for heat a circ pump turns on and gets 180 degree water from boiler then mixes down to 155-160 and sends it to that zone. When thermostat is sattisfied it stops circulating hot water. My system does not care what the outside temp is, it just gets "everything the boiler has" until the thermostat is satisfied. A little wastefull when its 40+ outside but still works great.

Radiant heat is quite different than others in response time. You do not set back thermostats. Typicall radiant systems take a day to come up 2 degrees, mine is rather fast at about 3 hours depending on outside temps. The benny is you are heating mass, objects not air. My ceiling temps are ALWAYS 3-4 degrees lower than floor level. Therefore you are not waisting energy heatng un occupied space.

It is quite gratifying when someone comes in the house to see everything and I show them the heat system and the first thing they say is "thats it??" yup... that's it...

Remember the Romans were doing this hundreds of years ago with NO insulation....no pex... and no WL 110 LOL!!! etc.

Is radiant for everyone??? Nope, but in my case it was a good fit.

Thank you very much for posting that info. I really like that system you have.

Thanks for sharing. Do you get expansion & contraction noise in the floor tubing & plates? Just curious.

I see a couple of spare valves toward the left of the boiler room pic.... are they capped? Where'd you hide the expansion tank? Good looking plumbing job.

Freddy,

The expansion tank is just behind the boiler in the pic (red). You do hear a little expansion of the tubing on some occations but for the most part it is pretty silent. I tried to leave plenty of room at the end of each run so expansion had an easy route. PEX is pretty amazing in its expansion coefficient. I will say it is WAAAAYYYY quieter than some friends of ours that had a 30 year veteran expert install their system. he he he

The 2 valves on the left are now plumbed in for the "dump zone". I ran a 70' run with plates stapled to the joists along with 2 slant fin baseboard (cheap) radiators on the floor in the basement next to a window. The boiler does use the "dump zone" on occasion and it seems to work well. I sized the dump zone for about 8% of boiler input on coal of roughly (8800 btu/hr)

glhracing wrote:a little expansion of the tubing on some occasions but for the most part it is pretty silent.

Good. I have some staple up tubing that needs to be replaced at some point *groan*. It's "Entran II".... part of the class action law suit of bad tubing. I got just enough money to buy new tube, but not enough to hire the job done. For now it's OK, just tiny leaks at the fittings. Anyway, the Entran is (was) rubbery and it is silent. I know "silent" is not to be expected with pex, but have never had anyone talk about it. I can live with occasional noise, that's fine.

My buddy Charlie had AWFUL noise with his baseboard pipes in the 2nd floor. Nothing could be done without ripping up the floor, or perhaps ripping out the ceiling. Nothing ever was done, but, when he went from oil to coal, his noise was reduced a LOT. Just because the heat is more constant. He's happy!

Ohhh, I see the tank now... sweet! Oh.... is the pressure relief valve piped down & stops about 6" from the floor? It's hard to see in the pic, but it looks like it might not be. If that ever blows off you will most certainly be glad if it's aimed to blow toward the floor. (plus it's the code).

glhracing wrote:All subfloors 3/4". First floor 1/3 tile, 1/3 bamboo, 1/3 carpet.
Second floor is ALL carpet.

All carpet areas use 7/16 padding, wished it was rubber (better transfer) and i did spec rubber but was not around when the install happened and we (wife) signed off on it not knowing the difference but it is just foam (poor conductor of heat). oh well...

I don't understand how heat can efficiently get thru all of that stuff to effectively heat your home lol.. Of course thats coming from a guy that uses forced air to heat

Lightning wrote:

glhracing wrote:All subfloors 3/4". First floor 1/3 tile, 1/3 bamboo, 1/3 carpet.
Second floor is ALL carpet.

All carpet areas use 7/16 padding, wished it was rubber (better transfer) and i did spec rubber but was not around when the install happened and we (wife) signed off on it not knowing the difference but it is just foam (poor conductor of heat). oh well...

I don't understand how heat can efficiently get thru all of that stuff to effectively heat your home lol.. Of course thats coming from a guy that uses forced air to heat

Lightning I feel the same way. The photo with all the copper pipes blows my pea brain. I am really interested that he can do it with way less than 110,000 btu's too. I use a big stoker 170,000 btu air blowing heater and it is not as efficient as his system plus he get endless hot water. I got to get thinking about next fall & winter now.

Joeski wrote:I am really interested that he can do it with way less than 110,000 btu's too.

Heating using hot water is quite a bit different than heating with hot air. First, it saves money because moving heat by moving heated water is much, much easier to do than moving heat by heated air. Next is a science type thing of heating that makes it so the higher the temperature, the less efficient the heat. Hot air is the hotest so it's the least efficient, it starts out a few hundred degrees. Steam is next, just over 210 degrees, then hot water at 180, then radiant heat as it uses hot water that is less than 180 degrees. The lower the temp, the better you can control it, and the more money you save. People get confused between efficiency of cost and efficiency of heat. You can have a less efficient heat source that costs less money. Confused? I am too LOL Look at it this way: If you have a burner that's 100% efficient, but if you lose 99% trying to get the heat where you want it, that's not efficient. In every case, when the transfer medium is hotter, you lose more of it along the path of getting it from here to there.

SO.... radiant heat is more efficient because of it's lower temperature, but, also, it's got other systems beat in other ways: It heats the floor. If your feet are warm, you feel warm. It does not stratify the air. The temperature at the ceiling is much lower than other systems. A cool ceiling saves a BUNCH of money. Instead of 83 degrees trying to escape, it's more like 70 or 72. It tends to heat living things more than objects. People and animals feel the radiant heat. That means you can keep the house 68 and feel warmer than a hot air system at 73.(again, lower temps trying to escape) Finally, radiant is more efficient because it does not make the air move. Moving air costs money! Couple that with realizing that hot air ducts, radiators, baseboard, are always (and with good reason) put on the outside walls, radiant saves a big percentage because it is not moving air across cold windows, cold walls.

Carpet does slow up heat. You don't lose dollars as the heat IS in the house. Carpet makes for less efficient heat transfer through the floor, but it does not change the efficiency in dollars. The only thing is, thick padding & thick carpets might lower the transfer efficiency to the point that you do not move enough BTU's. If so you'll need either higher water temps in the tubing (now you might be dancing with losing dollars) or some baseboard to make up the difference on very cold days.

Finally, it's not that you can use a smaller boiler with radiant heat, it's that you need a larger one with other types of heat. With radiant, you are a slow steady heat. With other types of heat, the temp comparatively raises a lot when the device is running, and sits idle when not. Now the temp drops & you need a bigger device to get the temp back up.

Time for coffee!

Joeski wrote: I am really interested that he can do it with way less than 110,000 btu's too.

Simple. The house is tight and well insulated. His system will not work for everyone, but in the right application it would be very comfortable and economical.

Up in my area people sometimes learn the hard way that stable up radiant can't put enough heat into the structure on a windy day...you need to do your homework and see if baseboard is needed to supplement the radiant on cold days.

Thanks for your descriptions, observations, and opinions. Lot's of interesting things to ponder in this.
Neil

Great system!! I would have to respectfully disagree with the necessity of the heating transfer plates in a modern house. We recently(3 years old)built a 3400sft(1st story) home with a 38'x20' great room with 22' ceiling height. It is heated well with 5000'+of staple up 1/2" pex 8"oc..R19 walls and r50 ceilings. This was a favor/job for a close friend so some parts are still not finished.For example the bottom of the floor joists are still open to the basement. This has resulted in a 70* basement as well. I was a little concerned the 1st winter that he would be loosing too much heat to the basement. This has not been an issue though .The house heats great up here in northern NY next to Canada.He has a bar,dance floor, game room,etc.. in the basement so the heat in the basement is not lost heat. Now I need to get him to install a LL220 so he can turn the propane boiler into a backup unit.

Where in Northern NY?

Transfer plates may not be required, but I think the plates certainly help send the heat in the right direction...especially if the floor is carpeted.

Rob R. wrote:Where in Northern NY?

Transfer plates may not be required, but I think the plates certainly help send the heat in the right direction...especially if the floor is carpeted.

Lisbon, between Canton and Ogdensburg. I agree. I am sure, as well as the staple up system works alone, that the plates would increase heat transfer. This house has ~30%carpet with balance in laminate and vinyl. I am a self educated(father...beatings etc..lol)builder by trade so I am sure it "technically" may not be 100% proper . I know enough about heating to be dangerous.lol.
I would not have done a system of this size for a "regular" customer. I was only 80% sure it would work great.

Great system!! I would have to respectfully disagree with the necessity of the heating transfer plates in a modern house. We recently(3 years old)built a 3400sft(1st story) home with a 38'x20' great room with 22' ceiling height. It is heated well with 5000'+of staple up 1/2" pex 8"oc..R19 walls and r50 ceilings. This was a favor/job for a close friend so some parts are still not finished.For example the bottom of the floor joists are still open to the basement. This has resulted in a 70* basement as well. I was a little concerned the 1st winter that he would be loosing too much heat to the basement. This has not been an issue though .The house heats great up here in northern NY next to Canada.He has a bar,dance floor, game room,etc.. in the basement so the heat in the basement is not lost heat. Now I need to get him to install a LL220 so he can turn the propane boiler into a backup unit.

I am guessing that you are using higher temps without insulation or transfer plates in place.

I understand the theory of the plates, but if the floor will only transfer X number of btu's based on its characteristics, adding more tranfer ability under the flooring will not increase the transfer. Just heats up the space under the floor more and lowers the rate of transfer from the pipe/plates to the space/floor. A flooring material can be considered an insulator as well as a transfer medium. Having a low heat loss in the heated space is critical for proper operation at lower temps as Freddy describes. My brothers house was also full of the Entran and we removed it and put in Pex. Now he can run full temp(180) water through it and still not get enough heat. The house is well insulated with one inch of foam on all ceiling areas as most heat goes up and out. The 6ft x 8ft windows facing NW on a high hill overwhelm the ability of the floor to transfer enough heat. Once the space under the floor above the insulation reaches the temp of the water, there is nothing more to add with plates. They do not increase the ability of the floor substance to transfer the heat to the room above. The plates will probably allow the space to heat up quicker, but not get it through the floor quicker.

This is all good info, but does not explain why some systems work and others do not. The system with no insulation and just pipes should not work.

Kevin

all great comments and interesting to see different perspectives. One thing I found out when starting down this road of radiant was the difference in oppinions between all the people (plumbers/heat people/general joe) when it comes to how to do radiant. When it comes to the "correct" method I think there are many different ideas that work well.

as Freddie pointed out water is a very effecient method of transfering heat energy compared to air. The larger the temp gradient between to mediums the more opportunity for lost energy. Higher temp gradients also creat "stacking" or chimney effect, this is minimzed with radiant because of the relatively low temps used.

Rob R, you are correct. radiant tends to not work as well in poor insulated homes. I do get plenty of wind (top of a hill at 1850' and house faces due west (allegany ny) so climate here is very similar to yours, however we are fairly tight.

Ncountry, That is pretty awsome house for sure. sounds like you do a great job on it as well do you have any pics of the install??



Thanks to all for the comments