To different animals to consider, Hydronic radiant versus baseboard, in terms of the water temp they circulate. With true hydronic radiant, you want to circulate water that is around 110-120 degrees. The goal is for the finished flooring surface to not exceed around 80-85 degrees. The problem with converting baseboard to radiant hydronic is that baseboard systems typically circulate 180-degree water. Running water that hot through a tight hydronic floor system can result in thermal expansion and contraction issues with the floor. For best performance, it usually results in having to put a the hydronic loop on it's own circuit separate from the the baseboard water. There are a few ways that can be accomplished. You might be able to get away with circulating 180-degree water if you did something like a below-floor suspended PEX system in the joist bays. Not "staple up" with transfer plates, but simply suspending the loop a few inches below the subfloor. For 180-degree temps, I'd prefer to use copper over PEX. But that's a whole new thread in and of itself. If the room is well insulated, or has no exterior walls, in-floor electric mats can provide enough BTUs to heat the room space. You'd need to consider the BTUs per sqft that those systems provide. An alternative would be in-floor electric for simple floor comfort warming, and something along the lines of a Runtal electric or hydronic Omnipanel for room heating. The Omnipanel can put out enough BTUs to heat a room.

Placing the PEX for radiant heating is relatively easy. What's not so easy is determining if this is a waste of money for you. It was for us. 1.)We live in the South, where the cooling season is longer than the heating season. Very little chance of payback unless you operate the system for longer periods. The smart boilers needed to accurately control a system in a temperate climate are pretty spendy and complicated and not very DIYable. 2.)We have wide temperature swings, sometimes daily, which magnifies the slowness of the "thermal mass pendulum." We see this just with our heated bathroom floors (separate system). It's going to be 42° tonight, so turning on the heated floors will feel good. You have to think about that a couple of hours in advance, because it takes that long to warm up. By the time they're warm, they're too warm for most of the timeframe except for that brief period that was 42°. The next day when the swing is back up to 60° and the floors are still 80°, the bathroom is too hot and needs a window opened for comfort. 3.) We insulated the new addition so well that a plain 110 volt 1500 w spaceheater can keep it 60° in the winter, and a 2 ton AC in the summer. If we'd put the money we spent on PEX towards additional insulation (we just used 2x6 construction with "standard" type insulation instead of the new high tech products) then the simple addition of the forced air furnace would have been more than sufficient for truly comfortable heating in the winter. For many people who have a long heating season and awkward spaces that forced air isn't comfortable for, radiant heating can work "miracles". For people in warmer climates, or in climates with great daily temperature fluctuations, a radiant system is very often not the best choice for either comfort or the pocketbook. Do your research well, and don't get caught up in the hype thinking it's a "must have". It isn't. And, it's sometimes even a drawback to comfort. We've never fired up the radiant in the addition. We've never needed to, even in 0° weather. And the bathrooms do work wonderfully well (imagine 6 cats lying on their backs in bliss!) but are also inefficient monetarily and for true comfort when confronted with wide temperature swings in a day. They are great when the temps say in the 40's and below for extended periods of time, but that't not how our winters here operate. It's 40 for a couple of days, then back up to 55°, then down to the high 20's, then 70° (must be Christmas day!) and then you have a 50° drop into the teens and on down to 0°. Radiant isn't very efficient or comfortable with weather like that.

Yes you can have baseboard radiators and in-floor radiant. "Can they be in the same loop or zone?" That may not be the best way to plumb, as the radiators and in-floor will likely require different water temperatures (supply & return âÂÂT), flow rates and controls. Always use proper design and best practices for assured comfort and reliability, not easiest, quickest, cheapest hookup. Don't forget automatic air elimination and dirt separation. Proper placement of every component is crucial! Plan and document your mechanical room carefully with proper labeling, arrows indicating flow direction, supply & return and a DETAILED schematic that remains on-site and includes every component so that any technician coming on site can understand what they're looking at. HIRE A SERIOUS PROFESSIONAL - you'll be glad you did! IMO SR

foil faced single sided foil (no need or extra performance from double sided foil or foil bubble foil barriers) installed with foil facing into attic space. wouldn't waste my $$ on spray on. go to florida solar energy center and do a search on radiant barriers for correct install, unbiased, non-product selling information. Best of luck. I love my RB..diy all the way!