The ell of our house with kitchen, pantry and dining room has radiant floor heat. It has its own thermostat and several loops feeding off one manifold. We don't change the heat there over the short term. We might turn it down if we will be gone for a week, but we don't change it over the short term. In our baseboard heat in the rest of the house , the radiators change the heat fairly quickly since the water directly heats the air, but the radiant floor heat first has to raise the temperature of the floor and then the floor raises the temperature of the air above it, so it's a much slower process. I don't find that the rooms heat more than a degree above or below the set temperature. With 3 windows and high ceilings, you have a large air mass with heat loss through the windows, so your time to heat the bathroom from a lower temperature will always be long. To my mind, it makes the most sense to keep the bathroom temperature at whatever heat you like and leave it there. It's the nature of radiant floor heat to be easier to maintain temperature than to quickly change temperature.

There's a lot of good information in the healthyheating post, but unfortunately, some misleading/inaccurate info as well. The good - building a really efficient house is definitely the way to go. The better insulated and air sealed, the more stable the temperatures, and the less it will matter what type of heating system you use. As the poster noted: "Its not just about the flooring its about the system the building (affects heating load what you pay the utilities) the flooring affects resistance) the tube spacing (affects fluid temperature affects efficiency) .theyre all joined at the hip" I'm not sure what the comments about VOCs have to do with heating systems. I might be missing the author's point, but the implication I get from reading the posting is that somehow radiant heating helps reduce the VOCs in your home. I know that's not the poster's point, but the way it's mixed in with talk about radiant, it's quite misleading. To clarify, VOC levels are a function of materials used in the house and the fresh air ventilation rates. As for radiant heating efficiency. There is a lot of controversy surrounding the efficiency of radiant systems. The industry claim is that you can set your thermostats lower because the heat radiates up from the floor, resulting in greater psychological and physiological warmth. In actual practice, the studies have had conflicting results. While it is true that in a low-temperature radiant installation, you can operate water heating equipment at more efficient temperatures, it's not true that it's a slam-dunk savings in all situations. This is particularly true in basement radiant slab installations where a fraction of your heat is going downward to heat the earth or out the edge of the slab. This can easily result in a 10-30% efficiency penalty, or more depending on the installation. The comments about the emissivity of the floor material is a red herring. While the follow-up comment about the R-value of the floor material is valid. What matters is the ability of the system to transfer heat into the living space. Tubes in concrete, exposed, is most capable. Tubes hanging in the joist bay, under the wood floor under a carpet is a worst case scenario. It is simply not true that the floor material does not make a difference! Consider this - if you have a concrete floor and a carpet, both at 70F, which one will "feel" colder when you stand on it in bare feet? The feeling of "cold" that your feet pick up is due to the heat being more effectively transferred from your feet to the concrete floor than to the carpet. The thermal conductivity of the concrete is much higher than the carpet. The floor material makes a profound difference to the actual functioning of a radiant floor heating system. Also be aware of the flywheel effect. Large, heavy masses take a while to speed up and slow down. The same with thermal masses, like concrete slabs. They have a capacity of holding lots of energy. Because of this, they take a lot of energy to bring up to temperature. With a forced air heating system or conventional baseboard heaters, you can set the temperature back at night or when you leave for the day, saving considerable energy. With a high mass radiant system, it takes a lot more heating energy to get the slab up to temperature, so it is slower to respond. This applies to the time it takes to cool down also. Quoting from the EERE website: "Thick concrete slab systems have high heat capacity and are ideal for storing heat from solar energy systems, which have a fluctuating heat output. The downside of the thick slabs is their slow thermal response time, which makes strategies such as night or daytime setbacks difficult if not impossible. Most experts recommend maintaining a constant temperature in homes with these heating systems." This is particularly problematic in the spring and fall, when it may be in the 40's at night but sunny and in the 60's during the day. Ask people with radiant systems about their comfort in these situations and you'll find a fair number who are dissatisfied with the comfort. This is a good reason to keep a forced air system for heating as well as the radiant. Use the forced air for primary heating during mild weather and radiant when it's colder. The healthyheating describes this on their website under "myths". Unfortunately, the way it's discussed is highly misleading. Radiant heating systems do NOT act like heat lamps. Heat lamps operate at very high temperatures and have essentially zero heatup time. Heat lamps do work by radiant heating. In floor systems do not. They operate at very low temperatures and can take considerable time to warm up and cool down. Depending on the design, this can be many hours. Quoting from the EERE website: "Despite their name, radiant floor heating systems also depend heavily on convection, the natural circulation of heat within a room, caused by heat rising from the floor. Radiant floor heating systems are significantly different than the radiant panels used in walls and ceilings." I don't want to seem negative on in-floor heating systems. I like them and use them in my own tiled bathroom floors. But you need to know that it is not "child's play", even for a competent installer, due to complicating factors.

I see a number of issues here that you might want to speak with your heating contractor about and perhaps post back. What source of energy are you using for your hydronic heat? In-floor radiant will likely require a lower liquid temperature than your baseboards. What type of baseboards are you planning to install? Cast iron would be best, as they require the lowest fluid temperature. In-floor radiant spacing varies with supply temperature, as does Btu rating of all types of emitters (radiators). The nice thing about in-floor radiant when combined with high ceilings, as in the case of your first floor, is that anything happening above your head (~ 6-ft) is irrelevant, who cares? This is radiant; you don’t have heat the entire volume of air in the room. This concept coupled with the lowest liquid supply temperature design yields the greatest energy efficiency and monetary savings. Your piping distribution system has to be properly designed from the ground up for maximum efficiency and comfort – particularly for individual control of 2nd floor rads. Hire the right expert – regardless of cost! Regarding programmability on the 2nd floor, I would suggest individual mechanical thermostats for each emitter (radiator). This way each room will be its own separate ‘zone’ with a minimum of installation complication. If you were installing hydronic fan coils instead of radiators, you could then have, in conjunction with a geothermal heat pump, hydronic heating, domestic hot water heating and central hydronic cooling (air-conditioning) without ever having to install ducts or mini-splits! Design & documentation of the piping distribution, as well as boilers & HPs, is critical to comfort, energy efficiency & resale value. Hire the right expert – regardless of cost (Yes, I’m repeating myself)! IMPO SR Caleffi Thermostatic radiator valves

Is your staple up system heating both floors? If so, I would recommend adding sound isolation clips to the downstairs ceiling and ensure everything is sealed then call it a day. There are a lot of good resources out there for soundproofing information. I suggest looking at some of the home theater boards as they have collected a wealth of great information. I would not use any type of resilient underlayment system as they generally work by converting sound energy to heat energy and tend to not be conductive to either. There are some soundproofing materials with decent thermal conductivity, but they cost too expensive to be practical in a home. There are basically four principles to dampening sound... (1) Sealing, (2) Mass, (3) decoupling, and (4) resilient layers. With a staple up hydronic system, sealing and decoupling are likely your best options. Adding mass (thermal mass) can also be effective but your system is going to less responsive if possibly more efficient and I believe that one of the benefits of the staple up systems is their responsiveness. There are other options to add mass that is thermally conductive, e.g. fiber cement (hardieboard), either as a subfloor or an isolated thermal mass between the joists, but they are probably not worth it. Sealing, drywall isolation clips, and two layers of drywall you will get a lot of deadening. ETA: I am not an expert on this... Have a studio and a theater and was forced to do a lot of research to get around marketing B.S.