We are building a new home this summer with a geothermal system. We are from minnesota so it does get very cold. I want to heat the house with hydronic infloor heat. The house has a basement which will have the tubes in the concrete floor. The main level is where I'm not sure what to do. I have read and read on which way is the best and all i do is get confused. The main level is 1624 sq ft. We would like some tile, some hardwood and some carpet. What is the best way to put the tubing. Some of the places say the staple up between the trusses but to me that seems like about the worst way. Gypcrete but I read a lot of horror stories on putting tile and stuff on it ??? What are some other options warmboard? Looks pretty sweet but pretty expensive. What do some of you people on the forum have, do you like it??? What would you do different? Just looking for some opinions. Thanks for you time
blimes: Welcome. You caught a wet head that does geothermal radiant heating and cooling systems. If you want to build this summer we need to hurry. I have been to MN I get how cold it can get. Hydronic radiant heat gains somewhere in the 30% area in delivery over forced air, good choice. If the basement is poured concrete with good insulation and vapor barrier it becomes a high mass heat sink to help you get to spring. For the main floor All of the systems you mention have there pros and cons, so I guess we need to provide education you so that you can make an informed choice. Staple up is hard work and besides the need to add some sort of heat transfer treatment. Insulation under the staple up is a must. I have used dry products, but not warmboard. If you think you want a prefabbed installation system plan on spending some money, and plan on getting detailed loop maps. I have used extruded al plates with plywood turns with great results, but again a lot of planning. Wet pours over floors, gypcrete, is easy to install as one can free form the tubing location and it is rather easy to fudge a 300' roll of O2 barrier pex to fit the room. One the adds the pour which costs. There are good manufactures out there and good installers. There are ways to get around cracking issues with tile or stone. The only type of radiant panel I have not designed, installed and warranted is ceilings. I will be doing one soon on a long term historic renovation. We are currently installing a Tekmar 406 House Control on a system we have been working on for about six years. The home is 6,500 square feet with a 4,000 walk out basement. The home is heated and cooled with a pair of 5 ton water to water geothermal heat pumps with pond loops. We will be able to cool some of the load with the floors and the rest with the high velocity air handler systems. I can offer only one opinion at this point besides hurry if you are breaking ground this spring if it gets here. You need to know more so you can make choices. OK. Keep an open mind. Mark lake-erie-indoor-air-services.net
There is only one thing which of utmost importance, and that is to keep the supply temperature to the radiant floors as low as possible. Since in a small house like that the highest supply temperature dictating the buffer tank temp come from areas with carpets. Carpets and radiant floors is a no no, it is like wrapping your radiators in a blanket. Essentially you are adding an isolator. Wood is OK, tile is the best. Plus why would you have a carpet, you want to feel the warms of the floors! In order to keep the supply temps low, the pipes embedded in concrete in the basement should not be further than 8" O.C., and not more than 2" below the surface. For the main level, do not use staple up, again, they require the highest supply temperatures. You want to put something on top of the subfloors, with aluminum plates for conductivity. In my opinion, the Raupanel system is the best, since it allows the highest amount of heat transfer at the lowest supply temperature, due to the large amount of aluminum. Alternatively, the low budget version is to use generic aluminum transfer plates (radiantmax.com). Lived in Minnesota, I know your pain. Do not fall for general advise from radiant guys, combining radiant with geo is different. Again, heat is transfered with lesser delta T and higher flow rates, like in the loopfield. So make sure the delta T for the floors is less than 10F, and the radiant supply temperature is as low as possible. Our most efficient systems run with 85F supply temperature.
Doc: You are my hero again. 85* is my max radiant design temp. I thought I gave Raupanel a good review. Extruded aluminum is the best but it costs more. That is where the education comes in. The customer must know what he or she wants and do the ROI math that meets their checkbook. Mark
There is no free lunch in this world. Each 10F higher supply temp will render the system 15% less efficient, for life. So 30F higher supply temps for one zone (bedroom with carpets) will dictate 30F higher system supply temps, meaning 45% less efficient. This can mean easily $500-800 per year....a high price for cushy carpets in one room, which ensures that you don't feel the warmth when you walk on it.
...but, What about a Tekmar 406 with two driving temps? One for carpet one for hard low mass floors. Mark
Sure, but how do you pipe it. 2 buffer tanks? Or bring up the single buffer tank to temp every time you need to heat through the carpets? Once you put a carpet in, the simplicity and efficiency goes out the window!
The Tekmar logic uses one tank. The system I am installing has the tank with the warmer water then turns a PCS pump into a variable speed injection pump for the lower temps. Mark
But then you heat up the tank to higher temps, which impacts your efficiencies (higher refrigerant pressure), to only cool the water down again?
How about a few throw or area rugs for accents and walking comfort while preserving the most excellent radiant characteristics of hard floors?
