Retrofitting Radiant Heating
I don’t have any ceilings and I want to keep the actual pine subfloor as the finish floor. Planning to do a Retrofitting Radiant Heating. I was thinking of one zone per floor. Anybody has any experience with that? How is the comfort? How about the heating bills?
I don’t have any ceilings and I want to keep the actual pine subfloor as the finish floor. Planning to do a Retrofitting Radiant Heating. I was thinking of one zone per floor. Anybody has any experience with that? How is the comfort? How about the heating bills?
Wrong cmu.The idea of lower water temperature and the ability of radiant to transfer the heat not only to the floors,but to the objects in the space.The savings of running a boiler at 90-100 or even 120F versus 180F and up to create effective heating is greatly reduced.You have never used it yourself as you quoted and your ignorance on the subject is quite limited.You should listen and ask questions before you express an opinion that is not based on real life observation.I have installed radiant and design them.Unless you experience it,you will never know.
This is why the system has to be designed by a professional .After sallystag wanted actual customers to respond,i did not want to reply to this thread,but since you questioned the savings,i had to respond.The floor in radiant behaves like a large radiator,hence the reason for operating at a lower temperature,with less heat loss than a regular radiator and the savings from not operating it at a higher temperature.At this point,i will let the customers respond.
“The heating bills are normaly half or less of a comparible baseboard or convector system,”
Only if you’ve somehow managed to violate the laws of physics.
Heating is heating, given the efficiency of the boiler (radiators are 100%), pumping losses, and insulation of the space. What reduces the cost somewhat in radiant floor heating is that the water temp can be lower, and you can set the thermostat lower, because it’s perceived by the human body as equally comfortable. But it will never approach 50% savings.
Given the excessive cost of install, I’d never use it myself.
We have radiant heat throughout with 1 zone (on 3 loops each) per floor. Our room layout is fairly traditional though tweaked to allow for crossbreeze in summer on all floors which may also help in temperature equalization (to the extent doors are open). We have never had to tune the system by adjusting the manifolds nor do we have problems with cold / hot rooms (some minor variation to be expected with any system). Our heating bills are low despite heating the house very comfortably. From this perspective, adding the complexity of increasing the number of zones (to 1 / room!) seems like an unnecessary expense (now & in future maintenance). FYI we replaced our subfloor with warmboard which may be more efficient than an underpin retrofit. Also, we put a lot of effort into insulating/sealing the house wherever possible and I think this was very worthwhile.
i’m a customer. i had mine installed by aladdin plumbing.
as far as single zone/floor goes, i just seriously doubt that the whole floor of any house will be the same temperature throughout. the temperature will only be precise where the thermostat is.
some rooms are just colder than others.
seriously, just add a bunch of zones–whatever additional costs are involved, it’ll probably pay off in lower bills and increased quality of life.
it looks like perfect access in your picture–is the whole floor/ceiling open like that?
shouldn’t be a problem at all.
I can’t speak to the technical, as it was the previous owner who put them in my home. But I can say this: our heating bill seems quite reasonable, and the radiant heat is SO comfortable (seriously, it feels GREAT! never chilly, even though we keep the temp quite low). The heat is fairly inconsistent, however. Around five feet from a wall with exposed brick and a few feet from the drywalled walls, the floor is pretty cool–downright cold when it is very cold outside. Also, one section is quite a bit warmer than the rest, despite being on the same zone. We have poured concrete over the radiant, with no subfloor, crawl space, or basement (it’s a carriage house).
I have a friend that just designed and had radiant floors on a 4 storey brownstone. You can email me at casaban@optimum.net and I will give you her contact.
If I have one ZONE per floor that means that I have the same temperature on the entire floor, right?
If you had a case similar to the one of the picture above, is there any reasonable way to divide between rooms?
How much are we talking per installation? Can we talk about an estimated price per sq foot?
On this forum I see many answers from people who have installed “a lot of radiant floors” but none of these customers is responding. Please, I would like to hear from somebody who has not a direct interest in the subject, someone who is just a customer of all the contractors responding. Don’t get me wrong, I really appreciate all the answers, but I can just hire one contractor and above this post I already have more than I need. I would like to hear from somebody who has paid for the radiant heat or has installed himself or herself with a licensed and insured master plumber.
Sallystag,thanks for the feedback.What i meant was that in radiant a loop is defined as the point where the pex tubing began and after it is laid down,where it is finished connecting back into the manifold.You can have a large enclosed space for example a living room,recreational ,master bedroom etc,where you have long runs of the radiant pex piping;for you to have the whole space covered you may have to break it up with 2 sets of loops connected back to the manifold on 2 seperate ports.Each port represent a loop.A radiant designer will have 2 electrically controlled valves(or actuators )tied in electrically togetheron the manifold to create one zone of heating.This can expand to 3,4 or more ports,depending on the distance of 200 linear feet per loop.The 2oo or more number is used as a rule of thumb to allow better water flow in the system.Anything over that can create sluggish or no flow for each loop start to it’s finish.
The diameter of the pex pipe for an application like this should be 1/2 inch or greater to add more heat transfer to the floor.Aluminum plates are used to be nailed or stapled on the underside of the flooring ,with the pex tubing embedded into the plate to create more heating surface area to transfer the heat.On the underside of the floor good insulation is added to cut down on the underside floor heat loss downwards,but allow it upward.A foil based reflective insulation is often used.
You can put the second floor on one zone and keep it on one thermostat,with many loops,but it depends on the heat-loss factor for each room;if they are the same then it makes sense,because overzoning never makes practical sense ,since the heat energy from one space can convect to the other space.Always get a good radiant designer to determine this.The floor you have now can be used to do radiant,but because this type of system requires a higher water temperature than topical radiant application(100 or lower vs 120F or above.This is average,depending on design),the high efficiency boiler would not be operating efficiently and hence higher heating bills,but if it is designed right it is still cheaper to heat than regular hydronics.
Radiant heat is the best in comfort and efficiency but expensive to do properly. Do some research online, start here
http://www.radiantpanelassociation.org/i4a/pages/index.cfm?pageid=99
I agree with most of the above advice except you will not save half compared to hot water radiators. No way. Maybe 20% if you do a very good job.
If you like the pine leave it, it is virtually the same as any finish floor you would use. Just be careful of existing nails when you install the pex. Use at least a r-13 insulation below the pex. Be sure to use aluminum heat transfer plates. Shorter loops are safer but depending on heat loss 1/2″ pex loops can be as long as 300′. You need to do calculations.
Each floor can be a ZONE to a manifold which distribute to multiple LOOPS that can be controlled at the manifold.I’ve done a lot of radiant floors and there are many ways to do it right and many ways to do it wrong.If you want to discuss I’m at radiantbuilder@gmail